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GPS Problem Reports Status
GPS Problem Reports Status

Civil GPS Users are encouraged to submit reports of GPS problems to NAVCEN. A form to submit reports can be found on our GPS Problem Reporting webpage. Some information from those reports is shared here along with input from interagency partners and the most likely cause of the report.

Descriptions for each of the fields is at the bottom of the page.

* Fields are as provided by the reporting source and are unedited.
*Date/Time of
Disruption
Date
Submitted
Location *Type Description Cause NAVCEN
Date Closed
05/23/2019    9:30 PST 05/23/2019 San Mateo, CA to Palo Alto, CA Automobile User: Both built-in and mobile phone GPS indicated that I was in a different area than I was in while traveling between Foster City, CA and Redwood City, CA. Additional info: My satellite radio was offline at this time. By the time I reached San Jose, CA, systems were functioning normally again.

NAVCEN: Collecting interagency input.
None  
05/17/2019    2030 UTC 05/23/2019 Lancaster, CA Other Synopsis: 4 [equipment] were powered on between approximately 2030Z and 2100Z on 17 May 2019 in Bakersfield, CA. They were then flown aboard private aircraft enroute to Laughlin, NV. Despite being in what should have been a "hot start" mode, none achieved a GPS fix until 2200Z. Of particular note, three of the units achieved lock within 30 seconds of each other, despite being separated geographically by almost 100 miles. This seemed to suggest an external factor may have been involved. Detail: Five [equipment] units (SiRF Star III chipset) were used to log positions of aircraft participating in an air rally event. Note the [equipment] is a retail data logging "puck" being used in the aircraft for supplemental logging, not an air navigation application. The units log NMEA GPGGA sentences at 1 second intervals when a fix is available, but do not include the satellite count. Participating aircraft flew from Hayward, CA (HWD) to Bakersfield, CA (BFL) to Laughlin, NV (IFP). Units were powered on prior to takeoff and turned off after landing. During the first leg from HWD to BFL, all units operated properly on board the participating aircraft. During the second leg, from BFL to IFP, four units were powered on between approximately 2030Z and 2100Z in Bakersfield, CA. Despite being in what should have been a "hot start" mode, none achieved a GPS fix until 2200Z. The powerup time and time and position of first fix for the units were as follows: Powered at 2100Z ; fix at 220019Z N34-48 W116-58 near Barstow, CA Powered at 2045Z ; fix at 220025Z N35-16 W116-07 near Baker, CA Powered at 2104Z ; fix at 220048Z N34-41 W117-24 near Victorville, CA Powered at 2026Z ; fix at 221536Z N34-53 W115-11 near Goffs, CA The fact that three units achieved a fix within 30 seconds of each other, while being separated geographically, and with varying (and excessive) times since startup, seemed unusual. The aircraft were all at an altitude of approximately 7000feet MSL. A fifth [equipment] was mistakenly left powered up throughout the ground stop at BFL, and logged a complete track. No other GPS anomalies were reported by participants. A [different model GPS unit] that was powered up at Bakersfield in the same timeframe acquired a fix immediately. I am aware that GPS interference testing was being conducted at Twentynine Palms that day (Flight Advisory 29PALMS 19-01), with the affected area encompassing the entire route of flight from Bakersfield to Laughlin. However, the testing was scheduled to be completed at 1300Z. While this issue is likely to be a manufacturer specific glitch, I am reporting it to see if any external factors may have been involved.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

Since the user acknowledged other equipment in the same aircraft operated normally, and we have no correlating information, NAVCEN encouraged the user to contact their equipment manufacturer for assistance. NAVCEN requested additional information, including any information from their equipment manufacturer but the reporting source has not responded.
User Equipment  
05/20/2019    11:00 EEST 05/21/2019 Port Said, Egypt Marine User: Problem commenced when vessel arrived to the above mentioned position (this is Sea Terminal, vessel is moored alongside of Sea Buoys)off Port Said. First day 20/May/2019 it was continuously, every 5 mins GPS position lost. Second day, 21/May/2019 frequency of position lost reduced to very 20 mins position lost. Vessel is equipped with 2 DGPS units and fault caused on both of them. Following alarms / warnings observed on the screen during subject DGPS fault: 1. Alarm, No fix; 2. Alarm, HDOP over. End of report.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area.

This report correlates with the U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority. NAVCEN requested any additional information, including communication authority response details. Reporting source has not yet responded.
Unknown Interference  
05/15/2019    1300 (Arabic) Egypt Standard Time (+2:00) 05/16/2019 Larnaca, Cyprus Marine User: This is now a daily occurrence in this area. Apart from losing a reliable position, I also lose the ability to lock the yacht to a predetermined route, and more importantly, collision alerting through my AIS B transponder and [software]. If I cannot broadcast my position, then the system ceases to function. This is a major concern as I sail single handed to Israel, the Lebanon, and to Turkey. AIS is my primary watch method when I inevitably have to rest. The outage is always confirmed through 3 receivers plus my GPS [mobile phone] app which is very useful in proving that this is not an equipment malfunction, but genuine interference or jamming. Other yachts at Larnaca also confirm the problem. I took a video of the satellite status page on my [manufacturer] GPS which I can send you once I have the correct email address to send it to. This summer I have not made any long trips so far, so I am unable to establish the area affected. Thank you for your concern. This has to be stopped before someone has an accident.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area.

This report correlates with the U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority. NAVCEN requested any additional information, including communication authority response details. User responded that the problem has cleared. They will contact their equipment manufacturer and report the outage to the nearest communication authority.
Unknown Interference 05/24/2019
05/15/2019    19 EST 05/16/2019 Statesville, NC Transportation User: Traveling East on I-40 about 7:30pm EST. GPS location [on mobile phone navigation application] started instantly changing directions 30 or 45 degrees, running off road for 1/4 to 1/2 mile, then rerouting. The area was being prepped for repaving and crews were setting up. The issue continued until we were about 10 miles east of Statesville (about 15 miles from start). It happened again at another construction area between Mocksville and Winston-Salem, also at a construction site. and a third time entering Winston Salem (again a construction- repaving site.) It happened one more time during the drive - about 9pm EST east of Burlington, NC near Mebane, also in a repaving zone. I am concerned that new equipment to help the repaving contractors is interfering with the GPS receivers.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer or application developer for assistance. NAVCEN requested additional information, including any information from their equipment manufacturer or application developer. The user did not respond to our request.
User Equipment 05/24/2019
05/14/2019    21:40 PST 05/15/2019 Hawthorne, CA Law Enforcement User: For the past two days, our GPS receivers have been unable to obtain a GPS FIX in the area.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for assistance. NAVCEN requested additional information, including any information from their equipment manufacturer. The user did not respond to our request.
User Equipment 05/24/2019
05/12/2019    0100 UTC 05/11/2019 Port Said, Egypt Marine User: While at anchorage near the entrance to the Suez Canal. The vessel [vessel name] ships staff started receiving a GPS failure alarm from their equipment.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

NAVCEN: This report correlates with the U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority. NAVCEN asked if the user had contacted their equipment manufacturer. Reporting source did not respond to the request for additional information.
Unknown Interference 05/20/2019
05/06/2019    1724 (Arabic) Egypt Standard Time (+2:00) 05/09/2019 Port Said, Egypt Marine User: DGPS Error was the message displayed.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

NAVCEN: This report correlates with the U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority. NAVCEN asked if the user had contacted their equipment manufacturer or DGPS service provider. The reporting source did not respond to the request for additional information.
Unknown Interference 05/16/2019
05/06/2019    5am EST 05/06/2019 Mitchellville, MD User: I drive a semi. GPS is out as well as my ELD.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

User provided GPS screenshots that indicate no GPS received but no other information such as other devices with the same issue, or if the device has a clear view of the sky. User encouraged to contact their equipment manufacturer for assistance and asked to share manufacturer response with NAVCEN. User did not respond to request for additional information.
User Equipment 05/15/2019
08/15/2018    12:00 EEST 05/01/2019 Plovdiv, Bulgaria Transportation User: From August last year the clock in almost all [vehicle type] with original navigation are showing wrong date, the year is 1999 the daylight saving time is incorrect due to months mismatch, but the time is correct just 1 hour backward, it now shows November 1999 or something. This problem is massive a lot of people are complaining. Please tell me what happened from August last year so old receivers decode date and year wrong, but newer are alright.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area. Suspect GPS Week Number Rollover issue.

As the GPS Week Number Rollover may have been a factor, user encouraged to contact their equipment manufacturer for assistance. User acknowledged the issue is likely related to the GPS Week Number Rollover and their older navigation system.
User Equipment 05/08/2019
03/01/2019    7:00 EEST 04/30/2019 Tripoli, Lebanon Surveying User: we tried to relocate receiver and Antenna to another town but same performance (no GPS and having 7 to 10 GLONASS) we had another stations covering whole Lebanon and working fine

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

User equipment suspected. User encouraged to contact their equipment manufacturer for assistance. User did not respond to request for additional information.
User Equipment 05/08/2019
04/27/2019    2300 EEST 04/28/2019 Damietta, Egypt Marine User: Unable to acquire more than 2 sats, weak signal on sats acquired. 1 Additional GPS of same make and model with antenna located on other side of vessel is receiving normally.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area.

See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority. User did not respond to request for additional information.
Unknown Interference 05/06/2019
04/25/2019    1800 EEST 04/26/2019 Port Said, Egypt User: [Vessel] was effected by the repetitive loss of GPS signal, affecting radar, ais, and gyro input. [Vessel] location was the Port Said EGYPT anchorage. This occurred from 1800 24 April, thru 0330 25 April, while my ship and numerous other ships were attempting to transit the Suez Canal.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area.

See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority. User did not respond to request for additional information.
Unknown Interference 05/06/2019
04/24/2019    19:00 (Arabic) Egypt Standard Time (+2:00) 04/25/2019 Departure Limassol, Cyprus Marine User: During navigation from Limassol, Cyprus to Haifa, Israel, both GPS (1&2) signals were lost. During early morning signal went back but both GPS are showing wrong date (09 September 1999).

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

As the GPS Week Number Rollover may have been a factor, user encouraged to contact their equipment manufacturer for assistance. User worked with their equipment manufacturer, replaced equipment, and the issue has resolved.
User Equipment 04/30/2019
04/22/2019    14:55 CET 04/22/2019 Liege - Grace-Hollogne Transportation I have been heading from Grace-Hollogne (Belgium) to Frankfurt am Main (Germany) in my truck and issue of GPS fix occur. These errors have I been noticed on my smartphone and on my car-mounted navigation. After 2hours and 34 minutes I havent noticed any GPS fix only assisted GPS "jumps" on my smartphone between signal points from my operator. On [navigation] device screen sometimes blink a "searching" icon but it gets any better. Now I am standing on parking place on highway and still havent my GPS signal uplink.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

User encouraged to report the issue to the Belgian Institute for Postal services and Telecommunications and the Federal Network Agency (Bundesnetzagentur) in Germany. User did not respond to request for additional information.
Unknown Interference 05/06/2019
04/15/2019    9.00 UTC 04/17/2019 Abeokuta, Nigeria Surveying User: The GPS Receiver tracked fine. On downloading there are evidence of recording by the size of data acquired. On processing, the error is failed in single positioning. The coordinate is 0 for both Latitude and Longitude. This occur for different receivers and on many days.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

As the GPS Week Number Rollover may have been a factor, user encouraged to contact their equipment manufacturer for assistance.

User did not respond to request for additional information.
User Equipment 05/14/2019
04/15/2019    13:30 CST 04/16/2019 Abilene, TX Surveying User: On 4/15/19 - We were calibrating our GPS equipment used to perform highway construction when we began having issues with the accuracy of the GPS. We considered this to be a calibration/file issue and ran multiple troubleshooting protocols to fix the issue, however, after many attempts to correct the problem we were unsuccessful and headed home for the night.

4/16/19 - We began working again the morning of the 16th to resolve the lingering issue. After setting up our GPS equipment the number of satellites began to drop until eventually our equipment was not tracking any satellites. We are in the vicinity of an aiport and an Air Force base. Prior to this incident we were using a different frequency equipment which we found was supposed to have issues with the frequencies being used at the AFB/Aiport. We changed our equipment to run on 900 mhz frequency to avoid any interference and the equipment was running as it should. Then we began having issues as listed above. We have had a certified troubleshooter of equipment on site and they are in agreement that there is some type of interference or jamming occurring.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

Interference appears to be at 900MHz. User encouraged to contact the FCC Jammer Tip Line to report the suspected interference. User did not respond to request for additional information.
Unknown Interference 04/30/2019
04/14/2019    16 CET 04/15/2019 Warsaw, Poland Transportation User: Since Sunday 16.04.2019 our devices have a problem with number of satellites in Poland. At the moment, more than a thousand devices can see only 2-3 satellites. Can you tell us where the problem is?

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners. Suspect GPS Week Number Rollover issue.

User acknowledged the issue is likely related to the GPS Week Number Rollover. They are working with their equipment manufacturer and expect a firmware update to correct the issue.
User Equipment 04/24/2019
04/07/2019    00-00 Middle East Time (+3:30) 04/14/2019 Tehran, Iran Transportation User: It is something like a big noise. Since one week before all off car GPS modules involved. The problem is the date, location and clock is correct but date is 2099. today it is 29-8-2099. This strange mistake was reported from lots of cities in Iran.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

As the GPS Week Number Rollover may have been a factor, user encouraged to contact their equipment manufacturer for assistance.

User did not respond to request for additional information.
User Equipment 05/14/2019
04/09/2019    24 Brazil Eastern Time 04/13/2019 Apuarema, Brazil Surveying User: "precisamos trabalhar e temos apenas esses aparelho,grato"

NAVCEN made several requests for additional information and received no response. As the GPS Week Number Rollover may have been a factor, user encouraged to contact their equipment manufacturer for assistance.
User Equipment 05/14/2019
04/06/2019    11:00 Near East Time 04/08/2019 Fahud, Oman Surveying User: Our geophysical recording instruments was unable to get sufficient number of elevated GPS satellites intermittently on 6th April 2019 for time correction.Though we have communicated to our clients but it is necessary to get some information from GPS about disruption in this area. Kindly confirm.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

As the GPS Week Number Rollover may have been a factor, user encouraged to contact their equipment manufacturer for assistance. User did not respond to request for additional information.
User Equipment 05/14/2019
04/05/2019    03:00 CET 04/06/2019 Oulu, Finland Communications User: GPS Week Number Rollover expected on April 6th, 23:59 (GPS time). It appears GPS almanac changes were applied the day before affecting some GNSS equipment before the GPS WNRO. We were not prepared for the GPS WNRO prior to April 6th. Now we must hope that actual GPS week number rollover event will fix the situation. What changed and when did the changes happen?

NAVCEN: The U.S. Air Force points to Interface Specification IS-GPS-200, paragraph 20.3.3.5.2.2, Almanac Reference Time, which states: "The almanac reference time, t(oa), is some some multiple of 2(12) seconds occurring approximately 70 hours after the first valid transmission time for this almanac data set (reference 20.3.4.5). The almanac is updated often enough to ensure that GPS time, t, shall differ from t(oa) by less than 3.5 days during the transmission period." They go on to point out "For this reason, beginning late on JDay 094 [April 4th], the GPS constellation began, one satellite at a time, broadcasting almanacs with almanac reference times which, when un-truncated as necessary, translate(d) to a calendar date of 7 April 2019 (after the associated 1024-week rollover), correctly, and IAW IS-GPS-200."

User acknowledged the problem is related to the how their equipment is handling the GPS Week Number Rollover.

Additional user questions forwarded to interagency partners. Response to those questions still pending.
User Equipment  
04/04/2019    8:45 PM CST 04/05/2019 United States Communications At roughly 8:45 PM CST lost GPS Sync to various cell sites around the US. The common GPS is trend is dual cones feeding sync to UMTS and LTE technologies. To mitigate the issue Field Technicians have removed one of the GPS cones and have a master sync from LTE feeding UMTS. There was no back office or architectural changes to our network during this time that would have caused this failure. We are curious if there were any changes made in preparation of the GPS System rollover slated for tomorrow April 6th that may have affected the base stations to lose sync.

NAVCEN: The U.S. Air Force points to Interface Specification IS-GPS-200, paragraph 20.3.3.5.2.2, Almanac Reference Time, which states: "The almanac reference time, t(oa), is some some multiple of 2(12) seconds occurring approximately 70 hours after the first valid transmission time for this almanac data set (reference 20.3.4.5). The almanac is updated often enough to ensure that GPS time, t, shall differ from t(oa) by less than 3.5 days during the transmission period." They go on to point out "For this reason, beginning late on JDay 094 [April 4th], the GPS constellation began, one satellite at a time, broadcasting almanacs with almanac reference times which, when un-truncated as necessary, translate(d) to a calendar date of 7 April 2019 (after the associated 1024-week rollover), correctly, and IAW IS-GPS-200."

As the GPS Week Number Rollover may have been a factor, user encouraged to contact their equipment manufacturer for assistance. User did not respond to requests for additional information.
User Equipment 05/14/2019
03/28/2019    3:00 EST 03/28/2019 None provided User: WE are a business that has been in the same location for over 20 years yet, GPS/MAP QUEST cannot seem to locate. It sends our clients to other locations across town.

NAVCEN: User provided information on how to contact mapping software providers to update their location details.
Mapping Issue 04/24/2019
03/19/2019    1040 UTC 03/20/2019 Pireaus, Greece Other User: GPS signal lost has been report by other vessels in the vicinity.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

User encouraged to report the issue to the Hellenic Telecommunications and Post Commission.
Unknown Interference 04/16/2019
03/18/2019    22:29 CET 03/19/2019 Madrid, Spain Other User: At 10:29PM UTC+1 03/18/2019 we have detected alarms in a lot of GPS of our network. We saw GPS with more than 10 satellites when in most cases have 6 or 7 satellites. Could you check if you detected any incidence at this time?

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

User encouraged to report the issue to the Comisión Nacional de los Mercados y la Competencia.
Unknown Interference 04/16/2019
03/14/2019    13:51 GMT 03/14/2019 Redmond, WA Other User: multiple days observed a disruption in the morning hours in this vicinity. .GPX file is available. I run this area often and only see it in the morning.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

NAVCEN forwarded user data to the Federal Communications Commission Operations Center. FCC pointed out "it was likely that the [user device] was influenced from natural effects such as tall buildings and dense tree in that area. These factors (heavy foliage and tall buildings) reduce or completely block GPS satellite signals. In addition, many tall buildings in that described area also created a multi-path so that GPS signals bounce off buildings before it reaches the [user device]."
User Equipment 05/14/2019
03/07/2019    11:20 UTC 03/07/2019 Dongguan, China Marine User: All GPS above lost position at the same time. Captain confirmed that his AIS showing China flags vessels only – probably they are using Chinese positioning system BeiDou

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

User encouraged to report the interference to the nearest communication authority.
Unknown Interference 04/16/2019
01/11/2019    20:45 UTC 02/14/2019 United States Surveying User: Observation of GPS NANU times in relation to the time satellites are set to unhealthy do not match past NANUs and satellite status. What time should be used? The time listed in the NANU, or the time the satellite was set unhealthy?

NAVCEN: The GPS Operations Center provided the following response: In reference to your question, no maintenance activities were initiated prior to the SVs being set UNHEALTHY. Moving forward, the GPS Master Control Station will work to ensure the NANU more closely tracks the exact time the SVs are set UNHEALTHY to avoid misconceptions. Again, thank you for bringing this matter to our attention.
Other 05/07/2019
02/13/2019    03:26 EEST 02/13/2019 Beirut, Lebanon Marine User: The problem started at 13.02.19 / 0326 UTC , but at 0512 UTC the connection was restored till 0858 UTC. From this time the interference is continuously till present with a few times for only a few minutes no interference.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

See U.S. Maritime Advisory 2018-014-Eastern Mediterranean Sea-GPS Interference on the MSCI Portal

User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
02/09/2019    0150 Eastern African Time 02/10/2019 Hodeidah, Yemen Marine User: VESSEL LOST SIGNAL FOR A PERIOD OF 10 MINUTES. AT 0200 LT FULL DGPS SIGNAL RESUMED WITH NORMAL FUNCTIONALITY. I DID NOT NOTE WHICH SATELLITES WERE BEING TRACKED.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

See U.S. Maritime Advisory 2018-014-Eastern Mediterranean Sea-GPS Interference on the MSCI Portal

User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
11/15/2018    unknown PST 01/04/2019 Washington State Timing User: Ongoing GPS failures since December 2017 at several sites. Was curious if other entities have reported outages in this area. Running redundant receivers and antennas at equipment sites. Technicians report different manufacturer equipment would fail at different times of the day. One timing receiver is experiencing more failures. Equipment alarms and requires manual reset to lock back on to GPS signal. Just really hard for me to think it is an equipment problem while three of them at different locations are doing this same thing.

NAVCEN: Equipment alarm records provided by the reporting source indicate similar errors across several timing units used by the reporting source and appear to be typical for this equipment. Errors were momentary (less than one second) with an average of approximately 90 momentary errors per site over the course of a year. Some equipment initiated more alarms, but there seemed to be no correlation between times, locations, or types of alarms. Redundant antenna and receiver systems did not alarm at the same time. The reporting source contacted their equipment manufacturer who identified a firmware issue. Reporting source now believes the problems are equipment issues and will provide more information if it becomes available.

The GPS Operations Center reviewed the GPS Constellation and Control Segment; there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners. Coast Guard-operated Differential GPS did NOT observe GPS problems during 2018.
User Equipment 05/07/2019
01/15/2018    1900 UTC 12/13/2018 Austin, TX Automobile User: In post-processing of the L2C CNAV message, it was observed that ephemeris records for several SVs were in error. Specifically, Longitude of the Ascending Node and/or Mean Anomaly differed by 1 semi-circle (PI radians) as compared to LNAV ephemeris, on some SVs. We understand L2C is pre-operational; informing in the unlikely case this error had yet to be diagnosed.

Follow-up from user: Please disregard a problem report submitted earlier suggesting an issue w/ GPS L2C ephemeris at the period specified. Suspected issue was found to be with the receiver.

Closed as user equipment issue.
User Equipment 05/07/2019
12/04/2018    0930 Mountain Standard Time 12/04/2018 Denver, CO Research User: For the past several days I have been picking up PRN 4 (which does not exist AFAIK) intermittently, always with no elevation or azimuth in the NMEA (because not in atlas I would guess). Duration from a 1s to 1.5h, starting around 0600MST and stopping around 2000MST.

NAVCEN: PRN4 is being used to test SVN36. This testing was published in NANU 2018042. "ON APPROXIMATELY 10 OCT 2018 SVN36 WILL RESUME TRANSMITTING L-BAND UTILIZING PRN04. AT L-BAND ACTIVATION, SVN36/PRN04 WILL BE UNUSABLE UNTIL FURTHER NOTICE. ADDITIONALLY, NO BROADCAST ALMANACS WILL INCLUDE SVN36/PRN04 UNTIL FURTHER NOTICE."

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/07/2019
11/01/2018    08:00 EST 11/25/2018 Raleigh-Durham, NC Surveying User: The unit has ceased to display valid date and time information and reverted to the year 1999 without a reliable calendar day or clock time. This affects time/date of lunar and solar positions that were used for estimating positioning and also other conveniences such as sunset/sunrise. The date and time can be obtained from other sources that the handheld GPS easily. I contacted the manufacturer who denied any manufacturing defects and could not offer a solution except to obtain another device at my expense (out of warranty for several years). This is only reported for general information or recall, no response or solution is necessary unless there is a widespread recall or other issue that I am not aware of. Thru the last weeks even though the time/date was off the two dimensional lat/long have proven precise and the elevation above sea level continues to experience fluctuations as previously reported.(date/time of problem onset is estimated)

NAVCEN: There are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

The GPS Week Number advanced to 1000 on 22 October 2018. GPS Week Number in March 1999 was also 1000. User encouraged to contact their equipment manufacturer for assistance as it appears the GPS equipment is incorrectly handling the GPS Week Number.
User Equipment 05/07/2019
11/18/2018    14:50 UTC 11/18/2018 Hadera, Israel Marine User provided no description of their problem.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

See U.S. Maritime Advisory 2018-014A-GPS Interference-Eastern Mediterranean and Red Seas for further information on this interference. MSCI Portal

User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
11/17/2018    0245 UTC 11/17/2018 Straits of Tiran Marine User: While on route toward Aqaba, Jordan, the vessel experience 03 incidents of loss GPS signal in the straits of Tiran. These 03 incidents lasted approx. 10 mins each. Event occurred between 0245-0440UTC.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
11/10/2018    23:59:43 CET 11/16/2018 North Sea Marine User: 17 Seconds before midnight on 10.11.2018 vessel experienced date jump. After midnight date changed again. Information collected with ZDA NMEA Sentence and wrong date were observed for approximately 24 hours until date changed back to actual date.

NAVCEN: Appears the GPS equipment incorrectly handling the GPS Week Number. Recommend user contact the equipment manufacturer for further assistance.

The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.
User Equipment 05/08/2019
11/11/2018    11:33 UTC 11/13/2018 Usuda (Japan), Maui (Hawai - USA) ... Other User: On the 11th and 12th of November 2018, the IODCs of the ephemeris/clock information transmitted by PRN32 from 11:33:30 (11 Nov) to 02:00:00 (12 Nov) were the same as the ones used on the 10th of November from 11:27:30 to 22:00:00 while the navigation data were different, in violation of the GPS ICD 200 IODC repetition rule (unicity over 7 days).

NAVCEN: Response from GPS Operations Center: The cause of the IODC repetition error was the result of an issue experienced with the ground control system. The problem has been corrected.
ICD_Violation 05/08/2019
11/10/2018    09:00 CST 11/11/2018 Evansville, IN First Responder User: On 22 October the units began reporting a date of 11 March 1999. Time is correct, date is off.

NAVCEN: The GPS week number for both dates are the same (1000). User encouraged to contact their equipment manufacturer for assistance.

The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.
User Equipment 05/08/2019
03/29/2018    0900 EST 11/08/2018 York, PA Other User: My cell phone GPS does not function properly. I have gotten a new phone from the manufacturer which did not solve the problem. I have been speaking with my service provider and they are informing me that it is not a service issue but rather "my signal is being sent to the wrong satellite" and that they were unable to help me. They provided me with this link to file a report. I have used several different GPS apps, none of which work properly. Even when I am stationary these applications have difficulty finding my exact location and instead cast a large circle around my relative location. This has been going on for several months. It seems to be worse in more densely populated areas though it does not function well anywhere. Any assistance would be greatly appreciated.

NAVCEN: There are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

User encouraged to contact equipment manufacturer or application developer for further assistance. Most likely caused by incorrect equipment or application settings.
User Equipment 05/08/2019
11/04/2018    1800 (Arabic) Egypt Standard Time (+2:00) 11/04/2018 35 - 04.4N, 034 - 48.1E Marine User: We have encountered more severe than normal GPS interference tonight. Shortly after 1800 local we lost all 3 GPS units, 2 for navigation, and the third within the AIS unit. Wanted to keep you appraised as again this is the most severe case yet. Certainly seems like a beam has hit this area. Thanks and will let you know once it clears some, or if it doesnt by the time we get to our destination. Thank goodness for paper charts.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/08/2019
11/01/2018    1600 UTC 11/01/2018 Haifa Port, Israel Marine User: Erratic GPS signal reception.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/08/2019
10/29/2018    07:00 Near East Time 10/31/2018 Strait of Hormuz Marine User: This vessel possesses two GPS units of the same make and model. Both units intermittently lost signal during the listed time period. The units regained signal by themselves in under 30 seconds after disruption. The incident occurred during a westbound transit of the Strait of Hormuz into the Persian Gulf. The last observed disruption occurred in the vicinity of 25-30N; 054-03E. The number of satellites (And the satellites in use) was not recorded during the period of disruption. Currently, both GPS units register 31 satellites and are obtaining a position via the following eight: 20, 21, 29, 10, 15, 26, 16, and 25. The vessel is still in the Persian Gulf as of writing this report. A contracted service company believes a military base in the area was jamming the GPS signal. The Iranian military scheduled gunnery exercises in the Strait of Hormuz on the 29th and 30th.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.

User encouraged to report the issue to the Communications Regulatory Authority of Iran.
Unknown Interference 05/08/2019
10/21/2018    10:00 (Arabic) Egypt Standard Time (+2:00) 10/27/2018 Santorini, Greece Marine User: Ii is 7days that probably all [equipment] fishfinders do not synchronize date and time. All users experience the same malfunction. Please advise

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to report the issue to their equipment manufacturer and the Hellenic Telecommunications and Post Commission.
User Equipment 05/08/2019
10/22/2018    8:00 Mountain Standard Time 10/24/2018 Fort Collins, CO Timing User: Our devices experiencing fluctuation in GPS PPS nationwide. It is not restricted to one area or GPS model. Our tools rely on GPS PPS synchronization with 60 Hz power grid. Working devices all suddently failing starting 10/22/2018. Please advise!

NAVCEN: It appears the equipment is incorrectly handling the GPS Week Number. The GPS week number for both dates are the same (1000). User encouraged to contact their equipment manufacturer for assistance.

The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.
User Equipment 05/08/2019
10/13/2018    10:00 UTC 10/17/2018 Jeddah Port, Saudi Arabia Marine User: Before Departure from port of Jeddah Saudi Arabia in Red Sea both GPS were found out of order. There seemed to be GPS signal interference resulting in loss of signal, missing COG / SOG and absence of GPS signals affecting bridge navigation and other communication equipment. GPS screen showing no available satellites in the vicinity, no Lat/Long could be obtained. GPSs restarted - no effect. Pilot advised that tugs reported absence of GPS signal as well. After vessel was cast off situation remained unchanged so own position was obtained by visual and radar observations and frequently plotted in ECDIS as manual fix position. ECDIS was turned to Dead Reckoning mode. Approximately 10 nm away from port area both GPS recovered the signal. After calling few nearby vessels by VHF found out that GPS signal loss problem was common in this area. Also experienced that on private smartphones (verified by Master and 2/Off) it was impossible to obtain GPS position, the signal was not available.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space weather was reviewed and found likely to have impacted GPS performance. No correlating reports from other users or interagency partners.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal.

User encouraged to report the issue to the Communications and Information Technology Commission of the Kingdom of Saudi Arabia.
Unknown Interference 05/08/2019
10/16/2018    19:45 UTC 10/16/2018 Leesburg, VA Transportation User: At approximately this time +/- 10 minutes the unit (a high end bike computer w/ normal GPS accuracy of 9 feet) reported a -64% grade rather than the real of -1 to -3%. It also reported loss of GPS lock. It was actively searching for a lock which it had lost. Its estimated accuracy at the time was approximately 274 feet. The problem continued across a power boot of the unit. The problem resolved within about 5-10 minutes, achieving a lock with 9 foot accuracy.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for assistance.
User Equipment 05/08/2019
10/15/2018    0846 Eastern African Time 10/15/2018 Jeddah Port, Saudi Arabia Marine User: We lost the GPS Signal on all nodes while we are approaching the Jeddah Port today 15/10/2018, 0530z. Checked with the out bound vessels and they too does not have GPS Signals. Believed it has been jammed. Had confirmed with the departure ship [vessel] that they too have the same problem, but they received the GPS Signal once they are about 8 miles from the Port. Had checked with incoming ship [vessel] that they too lost the signals once reached the approaching area. Based on these two facts, conclusion is that it is localised to this port area only. When our Vessel is cleared of Jeddah Port and 7 miles away, GPS signal is back on all GPS receivers, GMDSS, SSAS,FBB etc,. Same as other ships have shared the information earlier. Best regards, Captain. Thank you.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space weather was reviewed and found likely to have impacted GPS performance. No correlating reports from other users or interagency partners.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal.

User encouraged to report the issue to the Communications and Information Technology Commission of the Kingdom of Saudi Arabia.
Unknown Interference 05/08/2019
10/08/2018    07:40 UTC 10/10/2018 Huddersfield, UK Communications User: Loss of GPS lock for approx. 4 minutes during visibility of PRN27. Issue ongoing. Receivers manually forced to holdover mode until advised otherwise. Request further details of actual issue affecting PRN27 for fault reporting purposes please.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for assistance.
User Equipment 05/08/2019
10/08/2018    0430 UTC 10/08/2018 Rochester, NY Timing User: Two large phase events occurred between 0430 and 0445 UTC on October 8th.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.
User Equipment 05/07/2019
08/01/2018    0730 PST 10/02/2018 Lakewood, WA Transportation User: For many months now, GPS goes off track when directly north of McChord Field on I-5.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.
User Equipment 05/07/2019
10/01/2018    0030 EEST 10/01/2018 Port Said, Egypt Marine User: Report received by email from the [vessel]. "While making the approach to Port Said, at 0030 thru 0215 and 0220 thru 0400 on 30 October we lost all GPS signal, with no fix during this time line. While at Port Said anchorage 31-22.8N, 032-20.1E), we lost GPS due to interference from 1930 thru 2040 on 30 October 2018. We had no impact to navigation while at anchor. Departure from anchorage and Suez Canal transit had no issues with GPS.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage.

See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
09/27/2018    1100 CET 09/28/2018 Plymouth, UK Marine User: The intermittent fault happened several times while going East across Bigbury Bay -where I have had block problems before - the system started again near Thurlestone and continued to work back to Plymouth except that the interval report along the route were not applied for about an hour. Past route can be seen on Marine Traffic - boat name [removed]

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.

Recommend user contact the UK Office of Communications. Report forwarded to the UK Centre for the Protection of National Infrastructure.
Unknown Interference 05/07/2019
09/11/2018    0330 GMT 09/18/2018 Kabul Communications User: On 11th Sept Approx, Kabul Meteorological Department reported they were unable to track weather balloons. KABUL ATC GPS clock and navigation systems and other users were unable to gain GPS lock. Incoming aircraft report losing GPS at approx 6 miles from the airport on approach, but regain on departure. Used a spectrum analyzer and detected no apparent interference, jamming, or particular transmission from any direction from middle of the airport between runway and taxiway.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.

Recommend user contact the Afghanistan Telecom Regulatory Authority for Assistance.
Unknown Interference 05/07/2019
08/29/2018    18:00 Middle East Time (+3:30) 09/12/2018 Tehran, Iran Communications User: Hi I find out that in all of the tehran we have td-lte GPS clock synchronization problem That most of the this type of internet service can not access to internet And also cant use [mapping application] and other GPS based application So please tell us Is this another sanction or not?!? Regards

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.
User Equipment 05/07/2019
09/07/2018    00:40 CET 09/06/2018 Bratislava, Slovakia Automobile User: Two different GPS tracking modules placed outside window cannot find GPS signal.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.
Unknown Interference 05/07/2019
09/06/2018    1359 CST 09/06/2018 Gulf of Mexico Marine User: Multiple vessels in our area experienced degradation of GPS signal resulting in elevated PDOP. GLONASS systems were unaffected.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, they informed us that due to the current GPS constellation there is abnormally high DOP in the Gulf of Mexico. It is only for a short time.

Additionally, there was an authorized GPS test in the vicinity at the date of the report. NOAA reported impacts to their equipment in the area. No other correlating reports from other users or interagency partner.
GPS Testing 05/07/2019
08/20/2018    1700 PST 08/21/2018 San Bernardino, CA Transportation User: GPS diagnostic screen on [equipment] showing two Satellites with no lock. With an accuracy of greater than 1200 ft. [equipment] showing 0 of 10 satellites tracked with no lock. [equipment] showing zero us satellites but showing 8 GLONASS satellites with lock. Strength average about 28 per GPS data app. Has been occurring across 2 days started in Barstow California satellite loss on GPS navigation unit has been occurring off and on across the 21st and across an area from City of Industry to San Bernardino California. GPS randomly receive signal from satellites number 10, 15, 16, 20, 21, 26, 27, and 29. Lock varies from Full to non-existent. Same as occurring on mobile phone and [equipment] Eld. Power cycle of all devices and downloading a GPS data for cell phone did not correct.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.
Unknown Interference 05/07/2019
08/10/2018    00:40 Phoenix Standard Time 08/20/2018 Scottsdale, AZ Other User: Testing mixed mode tracking Y-code and M-code, up to the time specified, tracking L1 and L2 M-code for PRN 26. Receiver lost lock on the L1 channel, L2 continued to track. Could track C/A, but not L1 for PRN 26 for the duration the SV remained in view. Observed other SVs with similar behavior at different times over a 3 day test period. Trying to understand why we lose lock on L1 but not L2.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.
User Equipment 05/07/2019
08/11/2018    1605 China Taiwan Time 08/11/2018 50 miles from Qingdao, China Marine User: Military/navy exercises being conducted south of our position. Disruption at intervals for the last 50 mins. Receiver use: Input to nav equipment, communications. Vessel at anchor.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.
Unknown Interference 05/07/2019
08/03/2018    11:30 EST 08/03/2018 Avon, IN Other User: My son wears a GPS watch due to the possibility of him wandering from school. Around 11:30 today, I received a “check in” notification that he was in Upland, IN. I called the school in Avon, IN (hours from Upland) and they confirmed he was in class.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.
User Equipment 05/07/2019
07/23/2018    1428 EST 07/24/2018 Port Said, Egypt Marine User: The [vessel] was moored in Port Said Egypt when the captain informed me that he lost the primary and secondary GPS. Disruption was intermittent. GPS also showed the ships location of west of Alexandria on at least one occasion. Ships contact information: [removed]. Please feel free to contact me or the ship directly if you have any questions.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
07/04/2018    1500 EEST 07/04/2018 Port Said, Egypt Marine User: Vessel at anchor in Port Said, Egypt. GPS units started alarming with NO GPS FIX alarms. Position verified using anchor range and bearings & manually fixing position on ECDIS. Other vessels in area are reporting GPS problems as well. GPS interference continued intermittently throughout the entire day.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
07/04/2018    1500 EEST 07/04/2018 Port Said, Egypt Marine Vessel was at anchor in Port Said, Egypt awaiting a canal transit on the GPS units started alarming with NO GPS FIX alarms. We verified our position using our anchor range and bearings & manually fixing position on ECDIS. Other vessels in area are reporting GPS problems as well.

See U.S. Maritime Alerts 2018-004A and 2018-004B for further information on this interference. MSCI Portal
Unknown Interference 11/14/2018
06/28/2018    0600 CST 06/28/2018 Rockport, Texas User: The problem are the directions given to truckers, etc, when attempting to visit our facility. Directions send the vehicles to the south side of the ship channel. Our facility is on the north side of the ship channel.

NAVCEN: User provided information on how to contact mapping software providers to update their location details.
Mapping Issue 05/08/2019
06/28/2018    10:00 (Arabic) Egypt Standard Time (+2:00) 06/28/2018 Ankara, Turkey Other User: I am developing a product based on [equipment], which uses [chipset]. I was not getting a valid fix since the morning (now is 16:00 local time). I have tried to get a fix with my cell and couldnt get a valid fix for a long time. The phone has seen just one satellite and it had a very weak SNR.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.
User Equipment 05/07/2019
06/15/2018    10:00 EST 06/24/2018 Powell, OH Transportation User: I pulled up GPS on my [mobile phone] to get a route. I used [mapping application] first and it said that no GPS was available at that time. I then tried [mapping application] and it was down too. I closed down both apps and tried shutting down my phone and still, nothing worked. I ended up finding turn by turn directions that did not use GPS. I used those but got into a car accident because as a new driver, I rely on GPS. When law enforcement (EMS and police) arrived on the scene, I told them that GPS was down. They said that their systems were down too. Were there any planned outages in our area around that time? If so, I wish that I had been warned somehow and saved from that dangerous situation. Many people rely on GPS in order to safely navigate, and an outage can cause accidents and even deaths.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.
User Equipment 05/07/2019
06/16/2018    11 Brazil Eastern Time 06/22/2018 Vila do Conde, Brazil Marine User: Every day in the morning time up to lunch time the GPS gives warnings about unsafe position.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.
Unknown Interference 05/07/2019
06/15/2018    0730AM CST 06/15/2018 Nashville, TN Other User: Mapping applications on three devices gave the wrong directions three times. None of the maps were anywhere correct. Was there a disruption or outage? Might not be anything but it was very odd. Also, the application seemed to be speaking jabberwocky at times during the ordeal of us being lost.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partner.
User Equipment 05/07/2019
05/26/2018    08:44 UTC 06/08/2018 Yellowknife, Canada  Other User: PRN18 failed to be measured near the period of an unusable (UNUNOREF) NANU covering part of the reported period. NANU 2018028-GPS SATELLITE SVN34(PRN18)WAS UNUSABLE ON JDAY 146 (26 MAY 2018) BEGINNING 0948 ZULU UNTIL JDAY 146 (26 MAY 2018) ENDING 0950 ZULU. IGS observations covered 0940-0948.

NAVCEN: Report forwarded to GPSOC. Issue was covered by the release of NANU 2018028.
None 05/07/2019
05/01/2018    16:30 EST 06/04/2018 Doylestown, Pennsylvania  Communications User: Indicated location was erratic and device was unable to obtain accurate GPS location even after device was reset after traveling 5 miles. Device works normally in other locations throughout the U.S.

NAVCEN: User provided information on how to contact mapping software providers to update their location details.
Mapping Issue 05/07/2019
05/10/2018    0008 GMT 05/31/2018 Fairbanks, Alaska Other User: Since 10 May, several balloon flights have been terminated due to possible GPS interference issues. Analysis points to a possible disturbance source of narrow beam transmission from the airport or in its vicinity.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There was an authorized GPS tests in the vicinity at the date and time of the report. No correlating reports from other users or interagency partner.
Authorized GPS Testing is announced on NAVCENs website.
GPS Testing 05/08/2019
05/29/2018    14:00 Near East Time 05/30/2018 Le Port Reunion Island Surveying User: GPS elevation inaccuracy greater than 10 cm between 1400 and 1430 and then from 1800 local time (UT+4). It is affecting about 10 or more receivers on site (all machines, survey boat, land GPS backpack, excavators) we are working with RTK mobile receiver link to a base station by radio ling. There are three RTK base station on site with dedicated radio link. We saw on the sky GPS predictions. That GPS N29, is in view between about 1700 and 1430 then coming back again from about 1800 (5 degree elevation mask). We will try to disable GPS N29 from our equipment. No further information provided.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.
User Equipment 05/07/2019
05/27/2018    0600 PST 05/27/2018 Bend, Oregon Automobile User: Getting a NO GPS symbol on our unit, tried resetting and powering on and off, no swings have changed since last use.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for assistance.
User Equipment 05/08/2019
05/18/2018    1730 (Arabic) Egypt Standard Time (+2:00) 05/18/2018 100NM off Port Said Marine User: For the past hour GPS signal is either lost or incorrect in approximately 5 minute increments. Vessels in the area are reporting the same.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
05/18/2018    1430 (Arabic) Egypt Standard Time (+2:00) 05/18/2018 35 NM North of Egyptian coast Marine User: GPS total signal loss on 3 occasions: 17MAY18 2354Z - 18MAY18 0031Z 18MAY18 0240Z - 0248Z 0340Z - 0341Z -[equipment] models track Cypress standard GPS with Differential beacon 320 - [equipment] models track a Differential spot beam service by paid subscription. Last noted GPS interruption was on 30 APR

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
05/10/2018    0954 UTC 05/10/2018 Port Said, Egypt Marine User: [Vessel] Tracking 85 East. Vessel is located in port, position keeps changing even though vessel is not moving. position is wrong in about 2-2.5hr increments; incorrect positions are not consistent.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
05/09/2018    6:45 EST 05/09/2018 Armenia, Quindio, Columbia Other User: All my phones, my friends phones, and tablets are currently experiencing this outage in Armenis, Quindio, Colombia.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.
Unknown Interference 05/07/2019
04/30/2018    11:00 EST 05/01/2018 Orlando, Florida Aviation User: [Our company] is a producer of high accuracy, aviation time, space, and position information (TSPI) equipment, primarily for defense. We develop, produce, and maintain TSPI equipment at the coordinates above. We have been experiencing nearly continuous interference over the past two days. The interfering transmitter is operating in the range approximately 1566-1576 MHz. The signal is a modulated signal and appears to be an out of band transmitter as opposed to a jammer. We have captured the spectra at several times. The interfering system is blanking our (and presumably other) receivers. We are well versed in GNSS systems and technology. The equipment being blanked is used in military flight test operations. The ongoing interference is impacting our ability to conduct operations. Please do not hesitate to contact me should you have any questions or need any additional information.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partner. Report forwarded to FCC for action.
Unknown Interference 05/07/2019
04/23/2018    8:30am Mountain Standard Time 04/25/2018 Colorado Springs, CO User: Going north on I-25 around Colorado Springs, CO., GPS insisted that I get off of I-25 at each exit instead of waiting for correct exit. It occurred entering and departing Colorado Springs, CO. area.

NAVCEN: User provided information on how to contact mapping software providers to update their location details.
Mapping Issue 05/07/2019
04/17/2018    11:00 EEST 04/18/2018 Romania and Vietnam Marine User: We have received reports from a shipyard in Romania and Vietnam having lost of GPS at a specific time of the day. In Romania, happens every day at 11:00 AM during about 5 minutes and in Vietnam happens at 3:00 AM or 1:30 PM depending of the position of the vessel. We would like to confirm that there are no known test/trials happening in this area at that specific time.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners. Recommended contacting the National Authority for Management and Regulation in Communications.
Unknown Interference 05/07/2019
04/18/2018    08:00 GMT 04/18/2018 EASTERN MEDITERRANEAN SEA Marine User: DISRUPTIONS EVERY FEW MINUTES, CONTINUING AT TIME OF NOTIFICATION. ALL VESSELS IN THE AREA ARE COMPLAINING ABOUT THIS ISSUE. NO GPS POSITION FROM MORE THAN 3HRS. SATELLITES ARE TRACKED AND DECLARED HEALTHY IN GPS RECEIVER BUT NO POSITION AVAILABLE. PLEASE ASSIST ACCORDINGLY.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
04/16/2018    1700 (Arabic) Egypt Standard Time (+2:00) 04/18/2018 Port Said, Egypt, N entrance of Suez Canal Marine User: Intermittent and very frequent loss of GPS signal (time and position) while vessel was approaching Port Said). Same was reported by many vessels in vicinity by VHF radio.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
11/06/2017    13:35:07 GMT 04/10/2018 Kume Island, Japan Marine User: At 13:35:07, the GPS time output jumped to 13:37:16. It remained constant with this time offset for 10.5 hours. At 00:03:37, it jumped backwards from the offset time to the correct time. It maintained this time afterwards. This is a mature installation. Clear sky view. Other GPS receivers in operation did not experience problems. Were there any constellation issues at that time? If not, can you postulate a fault mechanism that could cause a constant time offset like this? Note: Question 6 did not allow "2017" as the year the disruption stopped.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.
User Equipment 04/15/2019
03/22/2018    0200 (Arabic) Egypt Standard Time (+2:00) 03/26/2018 DAMIETTA PORT, Egypt User: GPS EXPERIENCES LOSS OF SIGNAL PROBLEM FROM LAST 5 DAYS. MOST OF THE TIME IT HAPPENS NEAR EGYPT, LEBANON AND IN EASTERN MEDITERRANEAN REGION.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
03/21/2018    20:00 (Arabic) Egypt Standard Time (+2:00) 03/22/2018 AT SEA, POST DEP PORT SAID, Egypt Marine User: Master deemed it necessary to send it as non-routine under "any other potential, including potential problems" as the matter concerns vessels primary navigational system. Note that vessel had experienced problems with both GPS units of "no signal, alarm 001" since the night of 21st mar 2018. The problem of "no signal, alarm 001" was experienced on both GPSs just after departing from Suez Canal, Port Said side, on 21st Mar 2018. The problem was very frequently experienced in 3/O & 2/O watches. Then intermittently in C/Os watch going into the morning 22nd Mar 2018. Pls note that we had called at least 4 ships in our vicinity and they all confirmed the same problem with their GPSs, though with varying frequencies. This of-course has had an effect on the ECDIS. When the signals were lost, the courses went haywire. ARPAs was also effected, positions were not showing up.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
03/21/2018    0400 EEST 03/22/2018 Suez Marine User: Vessel is West bound from Port Said to Gibraltar. Position stated is current one, problem with GPS position started in Port Suez on 21 March. This is ocean going ship with 3 GPS units (all same model) with no prior problems. Overheard on VHF other vessels experiencing GPS position issues. Can you confirm if the area is affected by malfunction, testing or other disruptions of GPS system? I suspected hardware problem, but it happens on ALL units and position is on and off. Thank you.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
03/19/2018    1100 EEST 03/19/2018 Cyprus Marine User: Sir/Madam, [we] have received information from multiple sources indicating a problem in receiving GPS signals on their equipment or having an accuracy problem., while sailing in the eastern Mediterranean. Could you please provide any information regarding this problem so the [we] can promulgate relative messages in case necessary? Best regards,

See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
01/01/2018    1100 AEST 03/19/2018 Southern Tasmania Marine User: Numerous high HDOP errors frequently occurring over previous 3 months. Our unit is set to alarm at HDOP>2.0, and the alarm has been sounding numerous times each day. Vessel operating in southern Tasmania region, within a 200 mile radius of the position given above. Occasional very high spike into HDOP>30, and 2 occurrences >100, with subsequent position shift of around 200 metres noticed on ECDIS. Backup GPS receiver also shows occasional high DOP error (not split into HDOP and VDOP), but not as high as main unit. Is this likely to be a receiver fault?

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.
User Equipment 05/07/2019
03/18/2018    0600 EEST 03/18/2018 Port Said, Egypt Marine User: We have 4 DGPS and 3 GPS receivers on board. All of them affected. GPS were lost and DGPSs are being affected with not stable position or lost. Disturbance still continuous.

NAVCEN: See U.S. Maritime Advisory concerning GPS Interference on the MSCI Portal. User encouraged to report the issue to the nearest communication authority.
Unknown Interference 05/07/2019
03/07/2018    500 PST 03/07/2018 San Francisco, California Automobile User: Since 5am 7th March we noticed that the L1 frequency has been marked unhealthy in the CNAV ephemeris message. This is still continuing at 5pm on the same day. All L2 CNAV ephemeris message indicate that the L1 is unhealthy. Additionally L5 is marked unhealthy however this was the case before 5am today as well.

NAVCEN: The L2C and L5 signals are considered pre-operational. A pre-operational signal means the availability and other characteristics of the broadcast signal may not comply with all requirements of the relevant interface specifications and should be employed at the users own risk. Refer to Notice Advisory to NAVSTAR Users (NANU) 2014038 and 2014039.
User Equipment 05/07/2019
02/19/2018    04:42 UTC 02/27/2018 Washington (USA), Yellowknife (Canada), Brest (France) Other User: On the 19th of February 2018, some IODE/IODC of the ephemeris/clock information transmitted by PRN#06 from 04:42:30 to 06:44:30 were the same (14,15) as the data used on the same day for that PRN from 03:53:00 to 04:42:30 while the navigation data were different in violation of the GPS ICD 200 IODE repetition rule (unicity over 6 hours) and of the GPS ICD 200 IODC repetition rule (unicity over 7 days).

NAVCEN: Forwarded the report to the GPS Operations Center: The cause of the IODC repetition error was the result of an issue experienced with the ground control system. The problem has been corrected.
ICD_Violation 05/07/2019
02/16/2018    1400 EST 02/16/2018 West Palm, Florida Marine User provided no details related to their issue of their issue.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.
User Equipment 05/07/2019
01/31/2018    0700 UTC EEST 02/01/2018 Bad Pyrmont, Germany Timing User: This morning I was contacted by my [colleagues] who both have observed an anomaly in the timing characteristics of the GPS signal. [Colleague]s GPS receiver did an internal measurement against a Rubidium unit coupled with a very long time constant showed a time drift of -45ns an then back to zero whereas [colleague] is measuring the GPS offsets agains its internal HQ OCXO showed a time drift of +150ns and then back to zero. Both have used different types of receivers, [colleague] was using a [equipment] design with our proprietary receiver technology where [colleague] used the [equipment]. Is there a known anomaly in the GPS signal on Jan 31th between 7.00 and 8.00 UTC ? We have checked the number of received satellites and have found no outage. Best regards,

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. No correlating reports from other users or interagency partners.
Unknown Interference 05/07/2019
01/08/2018    7:30 pm PST 01/25/2018 Hinkley,California Automobile User: Heading East on highway 58, near Hinkley, CA, the GPS in the navigation suddenly announced "off route and recalculating", when the map restored, it showed the vehicle to the north of highway 58. Over 5 miles it slowly moved back until it showed us back on the highway. we checked both our cell phones and they showed the same error. On our return trip on Jan. 16, the same error occurred going west on highway 58 also just west of Hinkley.

NAVCEN: No correlating reports from other users or interagency partners. User provided information on how to contact mapping software providers to update their location details.
Mapping Issue 05/07/2019
12/02/2017    13:57 EST 12/31/2017 New York City, New York Timing User: We have two receivers using separate antennas located on the west side of the building. The loss of timing happens ~4 minutes earlier every day. Problem started on 2 Dec at 1402 Eastern and last interruption was 30 Dec 1210 Eastern. Only recently started to log sats but it seems to happen when sat 12 is starting to be used by the receiver. This setup has been in use for >5 years with out coverage issue so I dont think that is the problem. We stay locked with 3 sats in view and this problem occurs with more than 3 sats. Confirmed there is no in band RF interference. We would appreciate any information since we are at a loss as what to do to remedy or mitigate this issue.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners. User informed the issue is most likely related to the location of the equipment and equipment settings.
User Equipment 05/20/2019
12/12/2017    8:45 am EST 12/12/2017 West Chester, PA Transportation User: Unable to acquire satellites even after restarting unit.

NAVCEN: User encouraged to contact their equipment manufacturer for further assistance. User later reported a software update corrected the issue.
User Equipment 05/20/2019
11/30/2017    2200 UTC 12/04/2017 Global Other User: GPS PRN22 orbit error started to wander off. Problem seen globally, but worst on USA East Coast and East Australia. We would like to understand the reason for the anomaly.

NAVCEN: The GPS Operations Center reported PRN 22 was healthy and performing nominally. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
11/19/2017    4:17 PM PST 11/20/2017 Concord, CA Other User: Mobile phone GPS application unable to locate user. Device reset corrected the problem. User Equipment 05/20/2019
11/07/2017    3am EST 11/07/2017 Worth, NY Communications User: Mobile phone has not been able to connect to GPS all day.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
11/04/2017    1000 AKST 11/04/2017 Anchorage, AK Other User: Regularly use GPS on mobile devices to set and monitor trails in the area. No app could find a signal so used GPSDiagnostic to determine what satellites were accessible. The app indicated that it could identify NO satellites.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
Unknown Interference 05/20/2019
10/28/2017    1500 EST 10/30/2017 Jordan Lake, NC User: First indication of disruption were intermittent wrong time of day displays (roughly 3 hour advanced). GPS location tracking was also interrupted intermittently while sailing within 2 miles of specified location.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
10/26/2017    12:00 EST 10/26/2017 Alexandria, VA Transportation User: Mobile device GPS applications could not load the GPS, error stated GPS unavailable.

NAVCEN: User encouraged to contact their map provider or mapping application developer.
Mapping Issue 05/20/2019
10/24/2017    2115 UTC 10/24/2017 Sea of Japan Marine User: Both GPS systems onboard have been inoperable. GMDSS system is working correctly. App on phone using wifi is also working correctly.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
Unknown Interference 05/20/2019
10/18/2017    0041 UTC 10/18/2017 Addison, TX Aviation User: Several pilots have reported a problem with a GPS outage in the vicinity of the airport. The problem is happening while landing and departing both runways, and all pilots have stated that their RNAV instruments malfunction when close to the airport.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

Authorized GPS testing was scheduled near the reported location and may have impacted GPS performance.
GPS Testing 05/20/2019
10/12/2017    1200 EST 10/13/2017 Scranton, PA Automobile User: I was traveling from Vermont to Winchester Virginia when, at some point, the gps advised to turn west on an interstate to Scranton PA. I got completely lost. All I would like to know is if there were any ongoing issues in that area yesterday.

NAVCEN: User encouraged to contact their map provider or mapping application developer.
Mapping Issue 05/20/2019
10/10/2017    0920 EST 10/11/2017 Macon, GA Other User: GPS unit could not fix any satellites until around 1300 on 10/10/2017. To be able to receive notifications of GPS constellation problems, where do I and or others sign up.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.

Provided information on how to subscribe to GPS information products through NAVCEN website. Directed user to the approved GPS testing page on NAVCEN website.
User Equipment 05/20/2019
10/01/2017    16:30 EST 10/01/2017 Ringwood, NJ Transportation User: The GPS was anchored at the last site that was used as a detour for traffic Road work. I attempted to restart the unit at different locations with no success.

NAVCEN: User encouraged to contact their map provider or mapping application developer.
Mapping Issue 05/20/2019
09/23/2017    17:30 Eastern African Time 09/27/2017 Djelfa Province, Algeria Transportation User: Hello, On 23.09 we detected a problem with the GPS signal in North Africa and Eastern Europe creating GPS initialization problems and time fix for our GPS tracking devices. Practically they have stopped working on large areas that was covered by over 5000 GPS tracking units. Today the situation in Eastern Europe is going back to normal but persist in North Africa. Please let us know the cause of the signal problems and how long will take for the signal to return to normal. Thank you

NAVCEN response: We have contacted the GPS Operations Center and they have informed us that: “After a recent ground system software update, we received reports of some users experiencing negative issues. As a result, we re-verified that our software update was indeed in complete compliance with IS-GPS-200 standards. Nonetheless, in order to continue to support all of our users to the maximum extent possible, we rolled back the software update to a previous version so that we can take the time to consult with the affected receiver manufacturer and proceed forward in a way to ensure dependable access to GPS for all users. In this case, as always, Air Force officials continue to work with their counterparts in the U.S. Coast Guard to analyze and respond to all user concerns.”

User equipment does not meet IS-GPS-200 requirements. You can find the Interface Specification (IS-GPS-200), dated July 2017, in the technical documentation section of GPS.gov under Interface Specifications (http://www.gps.gov/technical/).
User Equipment 05/20/2019
09/25/2017    09:00 CET 09/27/2017 Perugia, Italy Timing User: Civil Defense and Environemental Monitor application We have about 300 units which will stop to work if a cold start will happen. The unit cannot get basic information for first fix. They are installed worldwide in remote stations. Manufacturer of [manufacturer] reported the signal from GPS is no longer compatibile with these units, the units cannot be updated because the firmware is not accessible. We do not know the exact date of signal change, approximately the problem started in a time window between Mid August 2016 and 25 September 2016. Although this problem is generating costs to our company in terms or workaround and replacement of parts, there are many instrument that cannot be accessed easily and this will cause a interruption of services for the public interest. Thank you for your attention and cooperation.

NAVCEN Response: We have contacted the GPS Operations Center and they have informed us that: “After a recent ground system software update, we received reports of some users experiencing negative issues. As a result, we re-verified that our software update was indeed in complete compliance with IS-GPS-200 standards. Nonetheless, in order to continue to support all of our users to the maximum extent possible, we rolled back the software update to a previous version so that we can take the time to consult with the affected receiver manufacturer and proceed forward in a way to ensure dependable access to GPS for all users. In this case, as always, Air Force officials continue to work with their counterparts in the U.S. Coast Guard to analyze and respond to all user concerns.”

User equipment does not meet IS-GPS-200 requirements. You can find the Interface Specification (IS-GPS-200), dated July 2017, in the technical documentation section of GPS.gov under Interface Specifications (http://www.gps.gov/technical/).
User Equipment 05/20/2019
09/22/2017    1500 CST 09/26/2017 Dallas, TX Research User: Starting last Friday, 22nd we noticed that the two high bits of the 10 bit IODC became non-zero. With all space vehicles as far as we can tell being non-zero by this Sunday. This is causing an ephemerides decding issue in our firmware preventing correct download of this data. Is this new behavior going to persist? If not when will it end? Is it possible to ask that the high bits cycle through 0 at least once per 6 hours for each space vehicle? Best Regards

NAVCEN: We have contacted the GPS Operations Center and they have informed us that: After a recent ground system software update, we received reports of some users experiencing negative issues. As a result, we re-verified that our software update was indeed in complete compliance with IS-GPS-200 standards. Nonetheless, in order to continue to support all of our users to the maximum extent possible, we rolled back the software update to a previous version so that we can take the time to consult with the affected receiver manufacturer and proceed forward in a way to ensure dependable access to GPS for all users. In this case, as always, Air Force officials continue to work with their counterparts in the U.S. Coast Guard to analyze and respond to all user concerns.

User equipment does not meet IS-GPS-200 requirements. You can find the Interface Specification (IS-GPS-200) in the technical documentation section of GPS.gov under Interface Specifications (GPS.gov).
User Equipment 05/20/2019
09/25/2017    7:00 PST 09/26/2017 Hsinchu, China User: Dear Sir, Recently the 2 MSBs of IODC has been set to non-zero value, which is different from the zero value that has been in use for more than 10 years before. Although our engineers tried to be very careful in preparation of ROM code release for GPS chipset implementation, checking various test scenarios using GPS simulator, we still missed an issue in applying the 2 MSBs of IODC. This and recent change of those 2 MSBs becoming non-zero value caused about 2 million units of GPS receivers worldwide that worked perfectly for many years now suddenly have potential problem of unable to get position fix, we are beginning to get many customer problem reports coming in this week. May I ask if this IODC parameter will be set to a number < 256 again? And could the two MSBs of IODC be set to zero again as soon as possible please? Thank you very much.

NAVCEN: We have contacted the GPS Operations Center and they have informed us that: “After a recent ground system software update, we received reports of some users experiencing negative issues. As a result, we re-verified that our software update was indeed in complete compliance with IS-GPS-200 standards. Nonetheless, in order to continue to support all of our users to the maximum extent possible, we rolled back the software update to a previous version so that we can take the time to consult with the affected receiver manufacturer and proceed forward in a way to ensure dependable access to GPS for all users. In this case, as always, Air Force officials continue to work with their counterparts in the U.S. Coast Guard to analyze and respond to all user concerns.”

Encouraged user to supply additional information on impacts to user equipment and mitigations employed to deal with this change. Input shared with the U.S. Air Force.

User equipment does not meet IS-GPS-200 requirements. You can find the Interface Specification (IS-GPS-200) in the technical documentation section of GPS.gov under Interface Specifications (GPS.gov).
User Equipment 05/20/2019
09/20/2017    unknown UTC 09/26/2017 Worldwide Automobile User: It appears that the Subframe-2 IODC message two MSBs have changed from 0 to a non-zero value for the first time in the last 10 years in some or many GPS Sats. This is causing potentially 100s of thousands of [manufacturer] receivers to stop generating GPS fixes for some reason. When will the two MSBs of the IODC parameter be set back to zero again? Can this please be done as soon as possible so as to make these large numbers of fielded [manufacturer] receivers work again? Thanks much!

NAVCEN: We have contacted the GPS Operations Center and they have informed us that: After a recent ground system software update, we received reports of some users experiencing negative issues. As a result, we re-verified that our software update was indeed in complete compliance with IS-GPS-200 standards. Nonetheless, in order to continue to support all of our users to the maximum extent possible, we rolled back the software update to a previous version so that we can take the time to consult with the affected receiver manufacturer and proceed forward in a way to ensure dependable access to GPS for all users. In this case, as always, Air Force officials continue to work with their counterparts in the U.S. Coast Guard to analyze and respond to all user concerns.

User equipment does not meet IS-GPS-200 requirements. You can find the Interface Specification (IS-GPS-200) in the technical documentation section of GPS.gov under Interface Specifications (GPS.gov).
User Equipment 05/20/2019
09/19/2017    0800 PST 09/25/2017 Tacoma, WA Marine User: GPS related equipment was interfered with when a bus was near the Ferry Terminal serviced. [Ferry operator] investigated and trouble shot the incident and found that Bus was indeed the cause of the disturbance and [bus operator] agreed to take the bus out of service until the problem could be identified.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User determined the cause of the interference was a transit bus operating near the location. Coordination between the ferry operator and the bus operator determined the cause was unintentional interference caused by improper equipment installation onboard the transit bus. The installation was corrected and the issue resolved.
Unintentional Interference 05/20/2019
09/03/2017    21:30 CET 09/05/2017 Rotterdam, Netherlands, to Antwerp, Belguim Automobile User: While dringin, and despite several restarts of the system my build in vehicle GPS was systematically for about 30 min showing wrong location about half a mile to the east from correct position. At the same time a separate mobile phone navigation was showing correct position. This has not hapened previously.

NAVCEN: User encouraged to contact their map provider or mapping application developer.
Mapping Issue 05/20/2019
09/02/2017    00:39 EST 09/03/2017 Concord, MA User: I am near a highway; perhaps someone is using a GPS disruption box to avoid tolls. It happened again last night at around 10:27 EDT.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer, map provider or mapping application developer.
User Equipment 05/20/2019
08/30/2017    0100 CST 08/31/2017 Indiana to Illinois Transportation User: [equipment] as well as [equipment] GPS have not worked for more than 24 hrs. [equipment] GPS is displaying a red circle with line through it indicating no GPS service. [equipment] is continually down and states "all entries must be manual". Please help!

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
08/22/2017    730 EST 08/22/2017 Myrtle Beach, SC Automobile User: Mobile phone GPS application was not loading.

NAVCEN: User encouraged to contact their map provider or mapping application developer.
Mapping Issue 05/20/2019
02/06/2017    0000 CET 08/21/2017 Oberpfaffenhofen, Germany User: The reason I am contacting you relates to the test of power increase on part of the GPS constellations as announced by the USAF in January. I am wondering whether you can shed any light on the root cause of these DCB sub-daily switches and provide some recommendations how to best deal with them in code-based single point positioning and phase-based precise point positioning?

NAVCEN: The GPS Operation Center (GPSOC) stated these configuration changes were published in NANU 2017005.
GPS Testing 05/20/2019
08/11/2017    2200 UTC 08/16/2017 South Korea Timing User: one of our customers claim that their GPS swap time at UTC 2200 to UTC 2400 and have done so multiple of times. This unit is placed close to the north boarder. Technical engineers are now traveling to the unit so that we can get more details on what is wrong with the installation. The second case is about the Olympic games which will be in Soul next year, summer. I have been asked if I can keep the sync for the broadcast system even if GPS is gone. The new IP based Digital TV system need GPS or IEEE 1588 to work well so we need a stable sync to get the digital information forward. So my question to you is: Do you know if the US has an alarm system in this area for GPS disturbance? Who can we contact and ask for alarms? Please support us! [Submitted by NAVCEN personnel from e-mail correspondence from reporting source.]

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact the Korea Communications Commission to assist with identifying radio frequency interference.
Unknown Interference 05/20/2019
08/01/2017    00:00 EEST 08/10/2017 Helsinki, Finland Other User: GPS lack about every 10-20 sec and not give any information after 3 sec, it cycle that. I think that USA do that on purpose beacose Russian and China warships are Baltic sea near the Finland to practiced together! Not nice at all!

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.
Unknown Interference 05/20/2019
08/08/2017    0600 PST 08/08/2017 San Clemente Island, CA Marine User: For the last two weeks in our area of operations, we have been experiencing loss of signal on all 3 of GPS units. Our typical routes seem to be losing our position constantly. The last two days have been worse than usual. At times, we go from 3D to 2D and then to no fix at all. Please let me know if there is anything we can do to, or when we can expect to no longer receive these alarms.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

Authorized GPS testing was scheduled near the reported location and may have impacted GPS performance.
GPS Testing 05/20/2019
07/29/2017    2030 EST 07/30/2017 Charleston, SC Timing User provided no description beyond equipment type.

The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
07/29/2017    1950 EST 07/29/2017 York, PA, and Washington County, MD Other User: Call centers in York, PA and Washington County, MD experiencing GPS timing issues on their [equipment]. This report was taken over the phone by the USCG Navigation Center.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

Equipment is known to have a GPS Week Number Rollover issue that occurred in 2017. A firmware update was issued in 2017. It appears the user did not apply the firmware update. User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
07/23/2017    0915 China Taiwan Time 07/23/2017 Port Hedland, Australia Transportation User: Each Locomotive has two GPS rims fitted, on odd and one even and the odd GPS stopped working today here in Australia and also we have reports that the units in China also stopped working. These units provide location services for a Railway control system called ITCS and this has caused a total site outage and rendered the system inoperable due to the Kalman filter causing error and the safety system failing.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User reported a firmware update corrected the issue.
User Equipment 05/20/2019
07/22/2017    6:00 CST 07/22/2017 Walnut, IA Transportation User: Map screen just says no GPS signal from western Iowa all the way across Nebraska.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
07/12/2017    10:30 EST 07/12/2017 Elizabeth, NJ Automobile User: OUR PROBLEM IS MOSTLY ALL OUR CLIENTS, COMPLAINT ABOUT HAVING THE WRONG ADDRESS IN GPS. GPS GIVE THEM [address] ELIZABETH NJ 07208 INSTEAD OF [address] ELIZABETH NJ 07208

NAVCEN: User encouraged to contact their map provider or mapping application developer.
Mapping Issue 05/20/2019
07/10/2017    12 PST 07/12/2017 Tulsa, OK Timing User: Our receivers indicated a spike in phase error shortly after PRN 2 became visible. The phase error seemed to resolve itself when full signal strength was reached.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
06/24/2017    11:00 EST 06/24/2017 Charlotte, NC Aviation User: GPS reception was intermittent all day, when receiving a signal location was off by over 1000 feet, this was experienced while driving and while stationary flying multiple drones and lasted most of the day and was very unusual.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
06/23/2017    10:00am EST 06/24/2017 Ashtabula, OH Communications User: All 3 of my devices have put me about 250 miles south west of where i acually am. I live in Ashtabula Ohio and they all but me at an apartment in Galloway Ohio.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance. It is possible the user was experiencing a network error, or a problem with wireless services.
None 05/20/2019
06/22/2017    1010 Eastern African Time 06/22/2017 Black Sea, Novorossiysk, Russia Marine User: GPS equipment unable to obtain GPS signal intermittently since nearing coast of Novorossiysk, Russian. Now displays HDOP 0.8 accuracy within 100m, but given location is actually 25 nautical miles off actual location.

NAVCEN: See U.S. Maritime Alerts 2017-005A-GPS Interference-Black Sea for further information on this interference. MSCI Portal
Unknown Interference 05/20/2019
06/19/2017    08:00 am CST 06/21/2017 Austin, Houston and Dallas, TX Automobile User: [Mobile] map application - the arrow icon begins to move off the road, spin or otherwise not move at all. Eventually, a "GPS Signal was lost" message appears, second mobile map application - error message "No GPS Signal".

NAVCEN: User encouraged to contact their map provider or mapping application developer.
Mapping Issue 05/20/2019
06/10/2017    12:01 EST 06/10/2017 Stephens City, VA Other User: Mobile phone and GPS fitness tracker both received intermittent reception while traveling through the park.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
06/02/2017    1300 PST 06/06/2017 Wenatchee, WA Automobile User: Navigation signal strength is low or non existent.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
02/14/2017    2:00pm CST 06/02/2017 Barcelona, Spain Automobile User: [No description provided about a mobile phone problem.]

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found to be unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

The report was forwarded to the European GNSS Service Center. User encouraged to report the incident to the Spanish communications regulatory authority.
Unknown Interference 05/20/2019
05/24/2017    18:23 UTC 06/01/2017 Toulouse, France, and Athens, Greece Other User: On the 24th of May 2017, some IODE/IODC of the ephemeris/clock information transmitted by PRN#10 from 18:23:30 to 23:59:59 were the same (40, 41, 42) than the ones used on the same day for that PRN from 14:00 to 18:23:59 while the navigation data were different in violation of the GPS ICD 200 IODE repetition rule (unicity over 6 hours) and of the GPS ICD 200 IODC repetition rule (unicity over 7 days).

NAVCEN: Forwarded report to the U.S. Air Force which manages the GPS constellation. They report the cause of the IODC repetition error was the result of an issue experienced with the ground control system. The problem has been corrected.
ICD_Violation 05/20/2019
05/31/2017    10:45 EST 05/31/2017 Estero, FL Surveying User: We are seeing GPS drop from 5/26,5/30,5/31 at around the 10:40 eastern time for a 15 minute period, for the location. Antenna is roughly 15 feet above the ground with little multi-path.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found to be unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
05/28/2017    08:10 CST 05/28/2017 New Orleans, LA Transportation User: No GPS signal being displayed.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
05/22/2017    0600 EST 05/22/2017 Knoxville, TN Automobile NAVCEN: No information provided by user. No response to requests for additional information. None 05/20/2019
05/19/2017    3:00pm CET 05/19/2017 Turin, Italy Research User: Since 17/05/2017 GNSS signal at frequency L1=1575.42 MHz have been affected during the local afternoon hours, by spurious continuos wave signals. The main components of the spurious signal are at an offset of 0.5 MHz on both sides of L1. Further harmonics with lower power are also present. The investigation excluded that such interfering signal could be generated by local terrestrial sources, since it has been measured at several Km from the antenna with the same power level. Having observed a 24h repetition of the phenomena, the interference might be a case of intrasystem interference generated by GPS satellite with PRN 26 which was in view at the monitoring location for the 3 days during which the interference has been observed. The signal has been observed through our software receivers and by means of spectrum analyzers.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

The report was forwarded to the European GNSS Service Center. User encouraged to report the incident to the Italian communications regulatory authority for assistance.
Unknown Interference 05/20/2019
05/06/2017    1300 PST 05/18/2017 Wenatchee, WA Automobile User: For the last few weeks or so my newley installed [equipment] navigation system has shown only 0-1 bars of GPS signal. The week prior it seemed fine, but cant say exactly when it started only when I noticed. Sat 5/6/17 Went to a local town and GPS showed me over 60miles off of my current location this lasted for about an hour when all of a sudden the signal jumped to 3 bars and everything worked fine. Today 5/18 my signal strnegth again is 0-1 bars, but navigation seems to be farely accurate but jittery.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found to be unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
05/10/2017    11pm CST 05/11/2017 Porter, TX Transportation User: My wife is a [rideshare] driver and the [navigation] applications would not establish our current position as of 11 pm on the 10 th . As far as I can tell other drivers are having the same issue . My wife and I are computer literate and gone over phone and tablet settings multiple times to ensure it is not our devices. each time we found that the GPS cant locate our position or track our position while moving.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found to be unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
04/11/2017    1253 PST 04/11/2017 Gutersloh, Germany Agriculture User: Farmers in Gugersahol, Germany are reporting that there GPS units stop functioning.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found to be unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance. User acknowledged equipment issue.
User Equipment 05/20/2019
04/02/2017    1007 PST 04/04/2017 Channel Islands, CA Marine User: Several systems, across all of our assets at sea, all affected

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

Authorized GPS testing was scheduled within 200 miles of the reported location and may have impacted GPS performance.
GPS Testing 05/20/2019
03/29/2017    08:00 Mountain Standard Time 03/29/2017 Denver, CO Automobile User did not provide details of mobile device mapping software application error.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact equipment manufacturer or application developer for further assistance. Most likely caused by incorrect equipment or application settings.
User Equipment 05/20/2019
01/03/2017    11:AM CST 03/22/2017 San Angelo Airport Aviation User: The GPS systems in normal mode not military have been interrupted since the installation of the command and control system at the North End of our airport. During testing of the system the problem has been confirmed to affect both ground and air operations at and within 15 miles South of the airport.

NAVCEN: Report referred to FCC. FCC conducted an investigation and found no further interference events.
Unintentional Interference 05/20/2019
03/19/2017    2:36pm PST 03/19/2017 El Monte, CA User: I have lived her for over 1 year and no one has been able to use GPS.

NAVCEN: User provided information on how to contact mapping software providers to update their location details.
Mapping Issue 05/20/2019
03/10/2017    5:30 PM PST 03/11/2017 Condon, OR Automobile User: Travelled to Condon, Oregon on remote, unpaved roads. When I left Condon the unit directed me first south and then west.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
03/04/2017    2015 EST 03/04/2017 Lyons, GA Transportation User: Our home is located on the west side of the highway. GPS directs drivers to turn onto the east side of [the highway] rather than to the west.

NAVCEN: User provided information on how to contact mapping software providers to update their location details.
Mapping Issue 05/20/2019
03/01/2017    1743 Indiana Eastern Standard Time 03/01/2017 Clarion, PA User: Unit has 1-2 bars of signal in an area clear of trees buildings or high tension power supply. Unable to aquire location while driving through Pennsylvania.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
02/26/2017    1200 EST 02/27/2017 Williamstown, NY Automobile User: My GPS has been down and I would like to know when it will be up again.

NAVCEN: Contacted user and determined GPS unit was providing incorrect location. Another device was operating properly at the same location. User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
02/08/2017    0745 Mountain Standard Time 02/08/2017 Chandler, AZ Aviation User: There is a small corridor at the Chandler airport in Arizona that has a loss of GPS signal.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance.

Report referred to the FAA for aviation support and response.
Unknown Interference 05/20/2019
01/26/2017    18:00 GMT 01/31/2017 United Kingdom Timing User: This has been happening over the last 4 days we have seen a quantum leep in indications, our recivers are not the best and we are looking at replacing them but something has changed and we would like to know how we can compensate for the change as it is effecting service as we are getting time jumps

NAVCEN: 5 January 2017 the Civil GPS Service Interface Committee Executive Secretariat release the following message: Beginning 25 January 2017, Air Force Space Command (AFSPC) will conduct a limited duration test implementing an increase of the L1 C/A power level on the GPS Block IIR-M and IIF satellites (19 vehicles). The C/A power will remain within IS-GPS-200-H specifications and the power increase is not expected to increase the noise floor by more than 0.3 signal-to-noise ratio in the worst case. AFSPC reports, "We assess that there will be no adverse impacts to civil, commercial or military GPS users, but anyone who experiences issues during this test should address them through established reporting channels." Civil, non-aviation, GPS users should contact the U.S. Coast Guard Navigation Center at 703-313-5900 or online at http://www.navcen.uscg.gov/?pageName=gpsUserInput. Civil aviation GPS users should contact the FAA and file a report at https://www.faa.gov/air_traffic/nas/gps_reports/. All other nonoperational concerns or inquiries regarding this test should be directed to Air Force Space Command at a3sm.wf@us.af.mil.
GPS Testing 05/20/2019
01/05/2017    4:35 UTC 01/20/2017 Chile Law Enforcement User: There were large spikes in geozone alarms on 3 consecutive days caused by a country-wide GPS position shift >125 feet, generally to the SouthEast. This affected 5% of the 4000+ units deployed. The times of increases in Inclusion Zone alarms are: Jan 06-2017, between 04:35:00 and 04:40:00 UTC (5 minutes, 404 alarms) Jan 07-2017, between 04:37:00 and 04:45:00 UTC (8 minutes, 337 alarms) Jan 08-2017, between 04:06:00 and 04:09:00 UTC (3 minutes, 165 alarms) All units had >4 satellites in use (actual number unknown). Maps and other data are available for the 3 GPS shift incidents.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
01/18/2017    ~7:30 AM EST 01/18/2017 Binghamton, NY Automobile User: It was reporting incorrect speed. I was going 55MPH and it was reporting 58-63 MPH. It was reporting my position off to the east by about 200-500 feet.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for further assistance.
User Equipment 05/20/2019
01/14/2017    1845 CST 01/14/2017  Slidell, LA User: While driving Interstate I noticed phone was reporting "seeking GPS" several times.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported outage. Space Weather was reviewed and found unlikely to have impacted GPS performance. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer or mapping application developer for further assistance.
User Equipment 05/20/2019
11/16/2016    7h37 UTC 01/13/2017 Rennes, France Research User: I experimented high range error on PRN 32 (7h54 to 11h45) and on PRN 17 (20h00 12 to 23h48) the sixth of november 2016. Coul you confirm the issu please.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for assistance.
User Equipment 05/20/2019
01/01/2017    12:00 EST 01/10/2017 Elizabeth, NJ Transportation User: My business is located in Elizabeth, NJ. At the end of the block there is a bridge that has been closed for several years, however it is not updated on any GPS. So we have a lot of 18 wheelers that come down and have to make a u-turn in front of my business. I need to know how I can update this so it will stop happening.

NAVCEN: User provided information on how to contact mapping software providers to update location details.
Mapping Issue 05/20/2019
01/02/2017    3:00 EST 01/02/2017 North Carolina - South Carolina border Transportation User: GPS would say when you plug in that there isnt any satellites to connect to but when you drive for about 5 miles it would pick up connection. Today when being turned on, says no satellite connection and has yet to come on. Been on for approximately 4-5 hours driven about 100 miles, still no connection.

NAVCEN: The GPS Operations Center reviewed the GPS Constellation and Control Segment, there are no known anomalies that might affect GPS signal integrity at the time and vicinity of the reported problem. Space weather was reviewed and found unlikely to have impacted GPS performance. There were no authorized GPS tests in the area. No correlating reports from other users or interagency partners.

User encouraged to contact their equipment manufacturer for assistance.
User Equipment 05/20/2019

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Date / Time of Disruption: Date and time of the report as provided by the reporting source.

Date Submitted: Date the report was submitted to NAVCEN.

Location: The City and State location of the reported problem based on input from the reporting source. Latitude and longitude may be used for maritime reports.

Type: Installation type as provided by the reporting source. Choices include: Agriculture, automobile, aviation, communications, first responder, marine, law enforcement, research, surveying, timing, transportation, and other (with a fillable field).

Description: Description of the problem. This information from the reporting source is edited for clarity and to remove personal and equipment manufacturer identifying details. The description also provides constellation analysis information as provided by the GPS Operations Center, a determination if authorized GPS testing might have been a factor, and information on correlating reports from other users and interagency partners.

Cause: The most likely cause of the report based on interagency input.

NAVCEN Closed Date: NAVCEN collects interagency input and provides a detailed response to the reporting source for each report submitted. If there are no further questions from the reporting source, and NAVCEN has no other correlating information, NAVCEN will close the case. The results of interagency input will be included in the description field when the case is closed. This date may not correspond to the event end date.