Joelle Tessler, at AP, reports that a new nationwide wireless Internet service could drown out GPS signals and jam navigation systems in airplanes and cars.

The problem stems from a recent government decision to let a Virginia company called LightSquared build a nationwide broadband network using airwaves next to those used for GPS. Manufacturers of GPS equipment warn that strong signals from the planned network could jam existing navigation systems.

A technical fix could be expensive -- billions of dollars by one estimate -- and there's no agreement on who should pay.

The FCC and LightSpeed claim that the two networks can coexist safely. However, GPS signals are very weak and are susceptible to being blocked by strong transmissions on adjoining frequencies.

It seems strange that the FCC, which has always been very concerned about jamming key communications channels by consumer electronics devices, would allow this situation to take place.

In January, the FCC gave approval for LightSpeed to build a wireless network that would reach 92 percent of all Americans by 2015.

The FCC has ordered further tests.