Some critics called on Congress to scrap the regulatory process by which the FCC gave LightSquared a waiver to operate a ground-based network. The bands LightSquared plans to use were intended solely for low-power infrastructure to supplement a primarily satellite-based system, they said. After LightSquared proposed its plan last November, the FCC provided only 10 days for public comment and seven days for reply, rather than the 30 days that would be customary for such a proposal, Garmin's Straub complained.

"We call on Congress to fully investigate just how this process has proceeded to a point where the nation's GPS system is being put at risk by a single agency in the face of overwhelming government, private sector and citizen concern," said Craig Fuller, president and CEO of the Aircraft Owners and Pilots Association. He said Congress should force the FCC to have the Defense Department and Federal Aviation Administration concur before approving LightSquared's application.

In its own testimony, LightSquared laid out its new proposal and said it would not launch its network on spectrum that would disrupt GPS for a majority of users. Less than one percent of all GPS receivers in use are sensitive enough to be affected by LightSquared's network if it is operated in the lower part of the band, said Jeffrey Carlisle, executive vice president of regulatory affairs and public policy at LightSquared. He also noted that some testers, including RTCA, also saw potential in the use of the lower band.

"LightSquared will commence terrestrial commercial operations only on those portions of its spectrum that pose no risk to the vast majority of GPS users and will coordinate and share the cost of underwriting a workable solution for the relatively small number of legacy precision measurement devices that may be at risk," Carlisle wrote in his prepared testimony.

The IDG News Service