DoD Buzz

New Wireless Tech Jams GPS


UPDATED: With LightSquared Company Comments

ORLANDO-- Deputy Defense Secretary Bll Lynn has raised concerns with the Federal Communications Commission about a new technology used by a company called LightSquared that jams both military and civilian GPS signals. The Federal Aviation Administration shares the Pentagon's worries.

Air Force Gen. William Shelton, head of Air Force Space Command, disclosed the Pentagon and FAA's concerns at the Air Force Association winter conference today. Shelton told reporters that an unnamed GPS company had tested its gear and found that LightSquared's towers built to generate a 4G wireless network completely jammed reception. The FCC recently granted a conditional license to the company to begin building its network using L-band spectrum, "right next to" the GPS signal, Shelton said. The conditional license requires that Light Squared prove it does not jam other signals. The company would operate only in the United States.

The FCC has told the company to work with the federal government and the GPS industry in a working group to find answers to the jamming problems. The members and goals of the working group are to be presented to the FCC by Feb. 25.

The technical problem is that the GPS signal is weak and diffuse as it comes to Earth from satellites and the new technology overwhelms it, the general said. For example, a plane flying near one of the thousands of towers Light Squared plans to build would lose the GPS signal guiding it within 12 miles of a company tower. Since the FAA plans to phase in a GPS-based air traffic control system, that could be disastrous for the nation's civil aviation. Of course, military aircraft would face the same problems.

However, Jeff Carlisle, LightSquared's executive vice president for regulatory affairs, said his company has "absolutely no interest in interfering with GPS." He said the company has designed sophisticated filters to prevent jamming those GPS receivers. He believes that the test to which Shelton referred was performed recently by the GPS giant, Garmin, on two receivers. He said Garmin performed the tests using simulated filters, not the production designs his company spent $7 million designing and building to prevent interference.

Ironically, Light Squared's press release announcing the company's formation under new ownership last July stated it hoped to be "a disruptive force in the U.S. wireless landscape by democratizing wireless broadband services..." It certainly looks as if it might be disruptive.

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