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DOT News Masthead

Monday, September 10, 2001

Contact: Bill Adams

DOT 92-01

Tel.: (202) 366-5580

DOT Releases Report Assessing Vulnerability Of Transportation Infrastructure Relying on Global Positioning System

The U.S. Department of Transportation (DOT) today released the results of a study assessing the vulnerability of the national transportation infrastructure that relies on the Global Positioning System (GPS) (Adobe Acrobat).


The study notes that GPS is susceptible to unintentional disruption from such causes as atmospheric effects, signal blockage from buildings, and interference from communications equipment, as well as to potential deliberate disruption. It contains a number of recommendations to address the possibility of disruption and ensure the safety of the national transportation infrastructure.


The report was mandated by a Presidential Decision Directive and prepared by the DOT Volpe National Transportation Systems Center.


“This report provides a roadmap for addressing possible vulnerabilities in GPS so that we can continue maintaining the highest standards of transportation safety,” said U.S. Transportation Secretary Norman Y. Mineta. “The Department of Transportation takes this report’s findings very seriously, and we will be working to ensure that GPS will fulfill its potential as a key element of the nation’s transportation infrastructure.”


Secretary Mineta charged the administrators of each DOT operating administration to thoroughly review this report and consider the adequacy of backup systems for each area of operation in which GPS is being used for critical transportation applications. The administrators are to report their findings back to the Secretary within 60 days.


DOT, in consultation with the Department of Defense (DOD), sponsored the study to assure the continued safe operation of the U.S. transportation system. All modes of transportation are increasingly reliant on GPS and, according to the study, GPS is susceptible to various forms of interference. This study identified transportation operations that employ GPS, methods for GPS disruption, possible impacts to transportation safety, and approaches to ensure service reliability. Among the report’s recommendations:

  • Create awareness among the aviation, maritime and surface user communities of the vulnerability of GPS and the need to reduce degradation or loss of the GPS signal.

  • Implement systems to monitor, report and locate unintentional interference to GPS.

  • Assess the applicability of military GPS anti-jamming technology and work with DOD and industry to make appropriate technologies available for civilian uses.

  • Identify appropriate backup systems, integrity warning, or operational procedures for each safety-critical application.

  • Encourage the development of low-cost systems as backups to GPS.

  • Continue the ongoing GPS modernization program involving higher GPS broadcast power and the eventual availability of three civil frequencies.

In addition to the review of backup systems, the findings will initially be used by DOT’s operating administrations to strengthen safety-critical areas that have an impact on aviation, maritime, railroads, and intelligent transportation systems. DOT will work with DOD to take appropriate steps to address GPS vulnerability in order to assure safe, secure transportation.


The department will soon announce a public meeting, to be held in early October, to solicit views on the study. An additional public meeting will be scheduled by mid-December to present the department’s response to the study’s recommendations.

The report, Vulnerability Assessment of the Transportation Infrastructure Relying on the Global Positioning System, has been made available to the public to improve user awareness of the vulnerabilities of GPS and avoid over-reliance on GPS in safety-critical situations. It may be obtained through the Coast Guard Navigation Center website at NAVCEN.





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