Failure to comply with the build-out condition would result in the company's licenses automatically canceling. LightSquared could ask the commission to ease deadlines given the issues related to GPS interference.

Despite criticisms, the FCC has withheld final approval until the interference issues are resolved.

In June, LightSquared unveiled a new plan for deploying its network using a different block of spectrum that is farther away from the GPS spectrum band.

It also has agreed to limit the permitted power level of an estimated 40,000 base stations to avoid overwhelming the signals of GPS devices.

Recent test results have confirmed that use of the company's upper 10 MHz block of frequencies — not the lower block, the block that LightSquared now proposes to use for initial rollout of its network — interfered with GPS receivers used by the Coast Guard, NASA and the Federal Aviation Administration, and caused GPS receivers used by state police, fire, and ambulance crews to lose reception.

Jeffrey Carlisle, LightSquared's executive vice-president of regulatory affairs, has said the company plans to unveil a prototype receiver that will allow precision GPS devices to operate without experiencing harmful interference from LightSquared's network in the lower 10 megahertz block of spectrum.