LightSquared Tells FCC the GPS Industry Is to Blame for Interference

By Carlton Purvis


LightSquared is building a broadband network that would connect the entire country. Using transmitters on the ground and a satellite in space, its 4G service would be available anywhere in North America. Initial tests showed that even at levels below what LightSquared planned to operate, their powerful transmitters interfered with GPS signals. This caused some concern among the aviation community.

In June, the House Committee on Transportation and Infrastructure heard testimony from airline industry and GPS executives who slammed LightSquared for continuing its plans. Officials argued that LightSquared’s network and regular GPS signals could not coexist – the broadband signals would drown out the weaker GPS signal used by planes for navigation and public safety operations (See: House Subcommittee Explores Whether Wireless Broadband Expansion Could Affect Aviation Safety from Security Managment).

“No further development of this system can be allowed,” Craig Fuller, president of the Aircraft Owners and Pilots Association said at the hearing.

LightSquared tried for months to accommodate concerns by, for example, agreeing to operate stations at lower levels and suspend use of bandwidth adjacent to GPS frequencies, and even offering to share the cost of finding a fix for at-risk devices. Now, LightSquared has changed tactics and launched an offensive.

Jeffrey Carlisle, LightSquared executive vice president for Regulatory Affairs & Public Policy, filed a letter Thursday with the Federal Communications Commission, asserting that the root cause of any potential interference caused by LightSqaured’s network is a result of failure by the GPS industry to follow Department of Defense regulations.

“Had the GPS industry complied with DoD’s recommended filtering standards for GPS receivers, there would be no issue with LightSquared’s operations in the lower portion of its downlink band,” Carlisle stated in the FCC filing. Additionally, LightSquared says GPS devices are operating outside of their assigned frequency.

The DoD’s Global Positioning System Standard Positioning Service Performance Standard, issued in September 2008, says GPS receivers should filter out transmissions from adjacent bands in order to achieve ideal performance. FCC regulations assign and license certain operations and organizations to specific frequencies.

LightSquared argues that instead of following the directive, GPS manufacturers not only ignored them, but ignored international recommendations as well.

“The GPS industry has a responsibility to use its licensed spectrum in accordance with international and federal government standards – not for LightSquared’s sake, but for the sake of the American people who own the public airwaves and who fund the GPS satellite system,” LightSquared said in a press release on Thursday.


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