Since early reports indicate that LightSquared’s transmitters do, in fact, interfere with GPS signals, LightSquared yesterday announced that it would vacate the frequency that caused major GPS interference and move to one farther away, where tests had shown minimum interference. However, some GPS receivers would still be affected by the company’s 4G signals even in this frequency band.
Satellite navigation systems
In accordance with the Federal Communication Commission’s January ruling, LightSquared must, in its June 15 final report on GPS compatibility tests, show that “it is clear that potential GPS interference concerns have been resolved.” But hold that applause, GPS users.
“The test data discussed today makes clear that there is substantial interference to GPS if LightSquared turns on high-powered terrestrial facilities in the spectrum next door to GPS,” Trimble vice president and general counsel Jim Kirkland said today at an event sponsored by the National Space-Based PNT Advisory Board. Kirkland is also a founding member of the Coalition to Save Our GPS.
The controversy over potential interference to GPS from LightSquared’s planned nationwide network of powerful 4G broadband retransmitting stations has now drawn Congress into the dispute. Letters expressing concern about adverse effects of the LightSquared network on GPS have been sent to the FCC by House and Senate members.
Two events last month intensified the confrontation between LightSquared, a private U.S. communications company, and U.S. government and industry GPS interests.
The controversy over LightSquared’s plan to operate 40,000 high-powered commercial transmitters to provide nationwide Internet connectivity over a radio frequency close to GPS recently ratcheted up another notch with the undersecretaries of the Departments of Defense and Transportation jointly expressing concerns to the FCC about the threat of interference to GPS.
Following a certification and verification process, the European Commission approved the European Geostationary Navigation Overlay Service (Egnos) “safety-of-life” service for aviation last month. Egnos is closely similar to, and compatible with, the U.S. Waas satellite-based augmentation system that corrects timing errors in GPS signals, enabling GPS precision approaches and shorter, more-direct routes.
Representatives from a wide variety of industries, companies and associations, including AOPA and GAMA, have joined together to form the Coalition To Save Our GPS to resolve a “serious threat” to GPS.
At press time, the first of three monthly reports of the technical arguments between experts from LightSquared and the GPS community over GPS jamming was about to be issued.
A panel of experts, selected jointly by the GPS Industry Council and LightSquared Corp., is currently determining whether LightSquared’s proposed NAS-wide network of 40,000 powerful ground stations transmitting voice and Internet traffic could interfere with and potentially jam GPS receivers operating within their own FCC-protected frequency band.