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.
While the LightSquared broadband wireless network’s potential to disrupt GPS signals has been widely publicized, a lesser known problem is the potential of the system’s high-power transmitters to interfere with satcom.
Over the next three months, a panel of 14 experts will test and analyze whether LightSquared's proposal to transmit Internet data from a nationwide network of 40,000 high-powered ground stations will jam very low powered GPS signals operating in the immediately adjacent GPS frequency band.
Garmin reports that LightSquared’s proposed nationwide broadband Internet service could seriously interfere with GPS signals. As a result of this and other filed objections, the FCC is withholding LightSquared’s operational approval until a three-month independent expert analysis agrees that this will not occur.
The U.S. Departments of Defense, Transportation, Commerce and Homeland Security, as well as the civil GPS Industry Council–of which NBAA is a member–have filed objections with the FCC over a new satellite-enabled cellular broadband service from LightSquared.
The DOT Volpe Center’s September 10 report on the vulnerability of GPS to jamming and other interference, in addition to the events of the following day, have greatly heightened national concerns about the security of the satellite system and the degree of dependence that should be placed on it as the backbone of our future ATC system.
To counter the possibility of jammed and “spoofed” signals, the authors of a U.S. Department of Transportation report on GPS vulnerability released on September 10 recommend that GPS not be relied upon as the sole source in critical applications, including precision approaches.
The October announcement by Raytheon that it had won a Department of Defense contract–potentially worth $25 million–to develop next-generation anti-jamming systems for GPS underlines security specialists’ concern that GPS is now “an attractive target” for terrorists.
Navstar, the official U.S. Air Force program moniker for the constellation of satellites most of us refer to simply as GPS, has undergone a multitude of technical changes and upgrades in the nearly 30 years since a group of military and civil engineers first sat down in the Pentagon to talk about the far-reaching precision navigation concept.
Just when many thought loran was dead, it is coming back, albeit in a different guise. The President’s recently released FY2009 budget includes funding for the Coast Guard to continue operating the current loran network in readiness for its upgrade in 2009 to enhanced loran (eLoran).