GPS Signals Face Cell Phone Interference

June 23, 2011 09:12 AM

An oversight hearing was conducted in Washington, D.C., this morning to examine the potential impacts a fourth-generation (4G) wireless broadband network integrated with satellite coverage would have on Global Positioning System (GPS) reliability. Two transportation and infrastructure subcommittees participated. 

Debate centered around the 4G broadband network under development by LightSquared Subsidiary, LLC. LightSquared plans to put 40,000-plus high-power internet broadcast stations in operation across the United States. The stations would broadcast on the spectrum neighboring the low-powered GPS signal.
Testimony today from the U.S. Department of Transportation, U.S. Department of Defense, U.S. Coast Guard and industry representatives verified that there is insufficient data to demonstrate that LightSquared’s planned nationwide broadband signal would not interfere with GPS signals.
Testimony indicated the new system will disable or cripple, at the very least, GPS navigation and timing functions including the Department of Transportation air traffic control modernization effort (NextGen). Furthermore, opponents said the broadband system ultimately would put countless American jobs and even lives at risk.
A press release issued by the subcommittees ahead of the event stated, "Some in the aviation community have pointed to potential negative impacts GPS interference may have on aviation safety, air traffic control modernization, and job creation within the aviation industry.  Initial government testing has validated some of these interference concerns, including interference with civil, military, and U.S. Coast Guard receivers.  There are also concerns about possible GPS disruptions in marine navigation."
For agriculture, the concern is that the LightSquared network would severely hamper many of the current practices farmers routinely implement via GPS access, including planting, irrigating and harvesting practices. In addition, equipment currently used to implement such practices would be rendered useless.
Phil Straub, Vice President Aviation Engineering, Garmin International Inc., said the current plan by LightSquared is potentially disastrous as its signal is 4 billion times stronger than that belonging to GPS.
"It’s like a loud conversation versus a whisper, or like running a lawn mower in a library," Straub said and added: "Please do everyone a service and put this dysfunctional service to an end."
LightSquared spokesperson Jeffrey J. Carlisle, Executive Vice President, Regulatory Affairs and Public Policy for LightSquared, was politely adamant the system would be a positive venture for Americans nationwide.
"We have no intention of operating this network in a way that would cause danger to the American public," Carlisle said.
He added that LightSquared has worked proactively with the Federal Communications Commission (FCC) for nearly 10 years to develop the new network and is prepared to enter the marketplace at a lower bandwidth than the FCC originally approved in 2005, in order to not hamper GPS functions.
"The FCC decision in 2005 was not appealed or questioned," Carlisle added. "No one approached us to make a modification to our approved power levels (until the past six months)."
Carlisle said company shareholders had invested $4 billion to date in developing the new network, and that their investment had now been undermined.
The FCC is in large part to blame for the current situation, according to testimony by Craig Fuller, president of the Aircraft Owners and Pilots Association.
He likened the new network to a toxic drug.
"When a drug does harm, it does not come to market; or, if it does harm it’s recalled by the FDA (Food and Drug Administration)," Fuller said.
"I really think there’s a role here for Congress for oversight and investigation," Fuller said. "FCC has gotten away from the inter-agency clearance process.  They should be required to have signoff from other agencies that are going to be affected."
For more information from today’s hearing, including witness testimony, go to

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