More Tests Show GPS Interference From LightSquared's Network

A new set of government tests showed that LightSquared's proposed mobile broadband network disrupted the signal strength to all GPS devices in the test area, dealing another setback to the company's startup plans.

While all global-positioning system devices tested were affected, the severity of the loss of service varied, said Deane Bunce, co-chair of the National PNT Engineering Forum, a federal advisory group of engineers that oversaw the government tests. Bunce, speaking at a federal government advisory group hearing, said some devices lost signal strength while others were knocked out completely. For example, the government tests found that General Motors Co.'s OnStar system saw a "significant degradation of service" on most receivers tested. The interference concerns of GPS users have become a major problem for LightSquared, a wireless startup. The government tests will increase pressure on the Federal Communications Commission to slow down approval of LightSquared's network.