It's official: LightSquared interferes with GPS

The Defense and Transportation departments along with the multiagency Positioning, Navigation and Timing executive committee confirmed in identical statements transmitters that startup cellular company LightSquared plans to use for a national wireless broadband network caused "harmful interference to the majority" of general purpose Global Positioning System receivers in recent tests.

LightSquared's plans also hit another speed-bump yesterday when the House approved an amendment authored by Rep. Mike Turner, R-Ohio, to the 2012 National Defense Authorization Act barring the Federal Communications Commission from giving LightSquared the green light for commercial operation until Defense Department concerns about GPS interference from the company's network are resolved. President Obama is expected to sign the authorization bill tomorrow, once the final version is approved by the Senate.

In addition, the statement said, "separate analysis by the Federal Aviation Administration also found interference with a flight safety system designed to warn pilots of approaching terrain," but did not specify the system. A federal source who declined to be identified said FAA determined the LightSquared network caused interference with the GPS-enabled Enhanced Ground Proximity Warning System, which alerts pilots if they are too close to the ground.

Preliminary analysis of test data showed the LightSquared transmitters caused "no significant interference with cellular phones" equipped with GPS chips, the statement said.

LightSquared transmitters operate in a frequency band adjacent to GPS and when the Federal Communications Commission granted the company tentative approval to operate its network in January, FCC said the company needed to demonstrate -- in tests conducted with the GPS industry and federal agencies -- that its network did not interfere with GPS receivers before it could begin commercial operations.

Tests conducted this spring showed the LightSquared transmitters caused widespread interference with GPS receivers, particularly at higher frequencies. In June, LightSquared proposed to initially use only the lower 10 MHz of bandwidth further away from the GPS band, which required another round of tests that were completed Nov. 30.

Though LightSquared flunked those tests with the type of GPS receivers the general public uses, Sanjiv Ahuja, the company's chief executive officer, said the statement from the executive committee and Defense and Transportation departments "validates compatibility [of LightSquared transmitters] with the nation's 300 million cellular phones."

Ahuja added, "We profoundly disagree with the conclusions drawn with respect to general navigation devices. We are eager to continue to work with the FAA on addressing the one remaining issue regarding terrain avoidance systems."

A federal source said the final report on LightSquared tests will be presented to Ashton B. Carter, deputy secretary of Defense, and John Porcari, deputy secretary of Commerce, on Jan. 26, 2012.