GPS Interference

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LightSquared, Industry Agree: Signals Would Interfere With GPS

July 13, 2011

Findings submitted late last month by telecommunications provider LightSquared to the Federal Communications Commission (FCC) vindicate what opponents to the company’s plan to develop a nationwide wireless network have said for months: signals from the proposed network would unquestionably interfere with those used by existing Global Positioning Satellite (GPS) systems.

However, LightSquared’s report – submitted to the FCC June 30, following a two-week delay to allow the nascent company additional time to prepare – goes on to suggest the existing, well-established, GPS industry bears at least some responsibility for the situation.

“GPS device test results…show unequivocally that the interference is caused by the GPS device manufacturer’s decision over the last eight years to design products that depend on using spectrum assigned to other FCC licensees,” reads a LightSquared press release accompanying the report. “Rather, their only answer to a problem of their own making is to demand that the government simply block LightSquared from using the company’s own spectrum to roll out the first wholesale-only wireless broadband network for the entire nation.”

A separate report, filed June 30 by the FCC technical working group (TWG) tasked with resolving frequency-sharing issues, expressed little hope the two technologies will be compatible in the near future. The TWG was co-chaired by Charles Trimble, Chairman of the United States GPS Industry Council, and LightSquared Executive Vice President for Regulatory Affairs and Public Policy Jeff Carlisle.

“The TWG faced an extraordinary challenge of trying to determine if the laws of physics would allow the high-power LightSquared signals to coexist in adjacent radio spectrum with the low-power satellite signals of GPS over and above the complex regulatory challenges of managing spectrum sharing,” said Trimble. “In the end, the laws of physics won out.”  

As NBAA has reported, LightSquared aims to build 40,000 transmission towers across the U.S. to dramatically increase access to mobile satellite spectrum (MSS) communications. MSS is used by "cloud"-based computing services, and provides 4G wireless Internet access for laptop computers and smartphones.

Both industry testing and LightSquared’s own findings showed the potential for interference to signals from GPS satellites. Earlier this year, NBAA was among more than 200 entities that joined forces to form the Coalition to Save Our GPS, which is committed to resolving the threat to GPS and preserving its benefits for industries, government and citizens.

Congressional lawmakers have expressed concerns with LightSquared’s plans, as has the International Civil Aviation Organization (ICAO). Leaders of the industries most at risk from the potential loss of reliable GPS service, including NBAA President and CEO Ed Bolen, submitted testimony June 23 to a Congressional panel called to review those concerns.

“The general aviation community has historically been a leader in new navigation and communication technology,” Bolen’s testimony states. “Obviously, the introduction of such technology enhancements has the potential to provide welcome and needed benefits to the public. Our members are not opposed to the development and deployment of new or improved technology systems like LightSquared -- as long as it is conclusively proven that it WILL NOT result in radio interference with GPS systems or pose any threat to the global aviation transportation system.”