LightSquared and GPS Interference

Lets shed some light on LightSquared. Whats going on, is it politics or science? Why did The FCC pull the plug on LightSquared Wednesday? Interference to GPS systems from the LightSquared communications network?

LightSquared Subsidiary LLC, Reston Virginia-based Company plans to provide a nationwide 4G-LTE wireless broadband network of radio transmitters for high speed internet access integrated with satellite coverage.

On January 26, 2011, the Federal Communications Commission (FCC) gave LightSquared conditional approval to build its ground-based wireless network.

LightSquared would combine existing mobile satellite communications services (Sky Terra) with a ground- based wireless communications network, ATC (Ancillary Terrestrial Component) that use the same L-band radio spectrum as the satellites. The base stations of the LightSquared network would transmit signals in a radio band immediately adjacent to the GPS frequencies proposed using the lower 10 MHz signal range of its authorized spectrum (1526-1536 MHz) of the Mobile-Satellite Services (MSS) frequency band. LightSquared has already spent nearly 4 Billion on the project.

The GPS community is concerned because testing has shown that LightSquared’s ground based transmissions overpower the weaker GPS signals from space. Although LightSquared will operate in a different radio band, that band is so close to the GPS signals that overload jamming occurs to GPS.

On February 14, 2012 the National Telecommunications and Information Administration (NTIA) released the findings of the government’s three latest reports on LightSquared wireless network and GPS interference.  Basically the reports find LightSquared’s network interferes with GPS and there seems to be no practical fix.

On February 15, the Federal Communications Commission (FCC) gave Public Notice proposing withdrawal of the January 26, 2011 conditional waiver allowing LightSquared’s plans for its wireless network and proposing modification of LightSquared’s satellite license to prohibit building a ground based wireless network.

On December 31, 2011 President Obama signed the National Defense Authorization Act for fiscal year 2012. Section 911(a) forbids the FCC from approving operations of the LightSquared terrestrial wireless network until the FCC has resolved concerns of widespread harmful interference to military GPS devices.

Last year at the Air Force Association winter conference, Air Force General William Shelton, head of Air Force Space Command, said that a plane flying over one of the thousands of towers LightSquared plans to build would loose the GPS signal guiding it within 12 miles of a tower.

Rep Greg Walden (R-Oregon) chairman of Energy and Commerce’s technology subcommittee, questioned why the FCC allowed LightSquared to get as far as it had before discovering the interference problem. He claimed that the interference is the result of GPS devices receiving signals from outside of their designated frequencies, not from LightSquared signal bleeding into their designated frequencies.

This could turn out to be a political and technical scandal. Billionaire Philip Falcone’s Harbinger Hedge Fund has sunk 3 Billion in LightSquared is trying to swap frequency spectrum with that controlled by the US Department of Defense.

Are GPS devices operating in their designated frequencies? Will they be forced to make modifications to their devices to operate side by side with LightSquared? Was the FCC’s decision to pull the plug on LifeSquared political? What Next?

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