**NOTICE** The RTCM Special Committee 104 is suggesting retirement of RTCM Message Types 4, 8, 11, 12, and 13. Any users requiring these specific RTCM Message Types, please contact DGPS System Support by 1900Z November 15, 2009.

On April 18, 2008, the U.S. Department of Transportation approved a decision to continue the inland component of the Nationwide Differential Global Positioning System (NDGPS), which provides an accurate, highly-reliable, real-time GPS correction signal. The decision is based on the results of the NDGPS user assessment conducted by the Research and Innovative Technology Administration (RITA). RITA followed the plan announced in the Federal Register notice on NDGPS (72 FR 42219), assessing the current user needs and systems requirements for the inland component of NDGPS. The notice listed 10 factors for consideration. Information was gathered on these 10 factors through public responses to the notice (including responses from state and local governments, the private sector, and the non-profit sector), and through quantification of the mission requirements of other federal agencies using inland NDGPS. Discussions are ongoing regarding the future funding mechanism for inland NDGPS, and will be addressed in future budget submissions. This decision was endorsed by the National Space-Based Positioning, Navigation and Timing Executive Committee at their meeting of March 20, and publicly announced at the PNT Advisory Committee meeting on March 27. You may read the full NDGPS Assessment report.

To date, the US Coast Guard monitors and controls 38 operational NDGPS sites that belong to the DOT. The Coast Guard is a key member of the seven-agency partnership for the Department of Transportation’s NDGPS expansion initiative. The Coast Guard brings its expertise in building, operating and maintaining DGPS sites to the partnership. The other members of the project are the U.S. Air Force, the U.S. Army Corps of Engineers, the Federal Highway Administration, the National Oceanic and Atmospheric Administration, the Office of the Secretary of the Department of Transportation, and most recently appointed sponsor for the project is the Research and Innovative Technology Administration (RITA).

Major NDGPS projects for 2008 and 2009 include:

1. Continuing the evaluation and expansion of the high accuracy (HA) NDGPS concept.

Currently, Hawk Run, PA; Hagerstown, MD; and the Topeka, KS NDGPS sites are equipped to broadcast code and carrier phase observables under a test scenario. Testing is expected to continue for the immediate future to support ongoing system development. Pueblo, CO is expected to become the next HA NDGPS broadcast site in FY 09. Further information on the high accuracy initiative can be obtained on the Navigation Center's homepage, and at the Turner Fairbanks Highway Research Center's web site.

2. New NDGPS Sites

The following sites were approved to be constructed by the Policy Implementation Team to achieve Initial Operational Capability (IOC) in CONUS as funding permits. The preparations needed prior to construction of a proposed site include an Environmental Assessment (EA), a Formal Site Survey (SV), an Installation Design Package (IDP), and a Lease or Property Use Agreement.

• Bliss (ID) - Pending final EA and construction funding.
• Big Lake (TX) - Pending final EA and construction funding.
• Carlsbad (NM) – Site preparations complete, pending funding to construct.
• Marshall (TX) - Pending construction funding.
• Patten (ME) - Pending Environmental Assessment and construction funds.
• Sage Junction (ID) - Pending final EA and construction funding.
• Tucson (AZ) - Pending IDP and construction funding.
• St. Mary's - Construction is complete. Site is On-air.

3. Two new DGPS sites are being constructed in FY09 under the Coast Guard’s Maritime DGPS project. They are:

• Card Sound, FL -A replacement site for Miami site. Site construction is complete and site is on air for signal verification and testing. Site will be operational early May 2009.
• Eglin, FL - A replacement site for the Mobile Point site. Site construction is complete and site is on air for signal verification and testing. Site will be operational early May 2009.