L5 GPS Signal Now Being Transmitted from IIR(M)-20 Satellite

April 10, 2009

The L5 third civil signal from the IIR(M)-20 satellite launched March 24 successfully began transmitting today, as planned. The satellite is equipped with a payload designed to provide an on-orbit demonstration of the L5 signal.

Military & Government Editor Don Jewell reports that the L5 signal came online two minutes early at 0458 Pacific Time. "he signal was so strong and perfect the visual display of the amplitude spectrum looked like it was a simulation, but it was the real signal," Jewell said.

Jewell is attending a special event for the L5 signal turn-on today at Stanford Research Institute (SRI) at Menlo Park, California, using its 150-foot dish. Professor Per Enge from Stanford and Tom Nagle from the Department of Transportation were on hand as well as numerous personnel from the GPS Wing and Stanford Research Institute, Jewell said.

This signal will qualify for the US to maintain it's signal reservation for L5 with the United Nations' International Telecommunications Union (ITU). Captain Anil Hariharan from the GPS Wing will initiate the required ITU paperwork immediately.

The U.S. had until August to begin transmitting the L5 frequency from middle Earth orbit or it would lose its license from the ITU, freeing the signal for another country to acquire. “We’re just sending the frequency to lock in the license,” said Donald DeGryse, vice president for navigation systems at Lockheed Martin.

L5 is intended to refine GPS accuracy to land aircraft and other safety-of-life applications.

The signal was also received by an SRI-maintained 10-foot dish at the main campus in Menlo Park. The Jet Propulsion Laboratory received the signal at 04:58:18 on its 8-foot dish.

"The signal quality was so good and so strong that it was received by all the antennas as well as a specially configured Trimble GPS receiver," Jewell said. "We can unequivocally call this test a huge success."

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