GPS Interference

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GPS Benefits Outweigh LightSquared's Claims in Congressional Hearing

Committee Chairman Says U.S. Is 'Clear Leader in Precision Navigation'

September 12, 2011

At a September 8 hearing before a House committee, industry representatives expressed their concerns about the potential impact the deployment of a nationwide wireless communications network would have on Global Positioning System (GPS) signals, and weighed those risks against claims by telecommunications firm LightSquared that its 4G Long-Term Evolution (LTE) service could function without interference with the vital safety, economic, and technological system.

"The United States is the clear leader in precision navigation," noted committee Chairman Ralph H. Hall (R-4-TX.) The lawmaker referred to the nation's network of GPS satellites as "the gold standard," adding that "it is nearly impossible to quantify the impact GPS has on society and economic productivity."

Attendees of Thursday’s hearing before the Committee on Science, Space and Technology included Anthony Russo of the National Coordination Office for Space-Based Positioning, Navigation, and Timing; Dr. Victor Sparrow, Director for Spectrum Policy and space communications for the National Aeronautics and Space Administration (NASA); Peter Appel, Administrator for Research and Innovative Technology Administration for the Department of Transportation; and Mary Glackin, Deputy Undersecretary for Operations at the National Oceanic and Atmospheric Administration (NOAA).

"Like the Internet, the Global Positioning System is an essential element of the global information Infrastructure," Russo noted in his prepared remarks. "The extensive and comprehensive testing done by LightSquared, the NPEF [National Space-Based Positioning, Navigation and Timing Systems Engineering Forum], and the GPS industry conclusively demonstrates harmful interference from LightSquared's intended deployment of their high power terrestrial broadband system."

LightSquared has sought approval from the Federal Communications Commission (FCC) to deploy its network since late 2010. In January, the FCC granted a conditional waiver for the upstart communications company to offer wireless broadband services on radio spectrum adjacent to the frequencies used by GPS receivers. Following an outpouring of concerned responses from members of the U.S. House and Senate, the International Civil Aviation Organization (ICAO), industry leaders and military officials, the FCC determined the company could not launch its service until the extent of demonstrated impact to GPS could be mitigated. A final decision from the agency may come by the end of September.

LightSquared has offered to limit its broadcasts to the lower limit of the spectrum in question, a move the company claims would reduce GPS interference; however, NASA's Dr. Sparrow disputes that assertion. "Mitigation options for preventing the disruption of GPS by the deployment and operation of the LightSquared network, including a proposal to only use the lower 10 Megahertz channel of the planned two-channel deployment, were identified in the TWG and NPEF Reports," Sparrow said in his remarks Thursday. "However, none of these options have yet been demonstrated to be effective in mitigating potential interference to GPS."

Glackin called GPS "a key enabler" for her agency's mission. "From daily weather forecasts, severe storm warnings, and climate monitoring to fisheries management, coastal restoration, and supporting marine commerce, NOAA's products and services support economic vitality and affect more than one-third of America's gross domestic product," she noted.

In his remarks, Appel specifically cited the impact to aviation use of GPS in his remarks. "This would impact GPS receivers onboard over 60,000 aircraft, resulting in substantial retrofit costs," he said. "Benefits of providing more direct routes and improving capacity, as well as safety benefits of using GPS for approach and landing in all weather conditions, and addressing controlled flight into terrain and runway incursions, would not be fully realized."

Defending his company’s plans before the hearing, Jeffrey Carlisle, LightSquared Executive Vice President, Regulatory Affairs and Public Policy, alluded to LightSquared’s prior claims the problem lies not with his company, but with GPS manufacturers using signals outside their allotted bandwidth. [LINK:

"This is not a zero sum game," Carlisle said. "Americans do not have to choose between a robust GPS and a competitive broadband wireless network. They can have both. This is an issue of responsible receiver design…a technical issue, to be solved the same way it is solved every time a new provider deploys a wireless network in the United States."

NBAA has been actively involved in calls for a responsible solution to the LightSquared dilemma. Earlier this year, the Association joined the Coalition to Save Our GPS, which counts over 200 members dedicated to maintaining the safety and integrity of the GPS network.