WASHINGTON – LightSquared, a wireless-by-satellite network start-up created by hedge fund billionaire Philip Falcone, hit its first roadblock with new findings that its service interferes with global positioning systems.

A report filed Thursday to the Federal Communications Commission found that LightSquared’s planned operations could knock out 500 million GPS receivers used by police and firefighters, airlines, construction workers and consumers.

“Such a network would cause unacceptable interference to GPS operations,” the United States Global Positioning System Industry Council, found.

LightSquared simultaneously filed a proposal to the FCC that would avert much of the interference, the company said. The use of filters on its devices and GPS receivers could allow both technologies to operate on the same band of satellite spectrum, the company said.

The GPS industry disagrees, saying there are no technology fixes. But the FCC will ultimately decide whether it will allow LightSquared to pursue its aspirations of being a new competitor for mobile Internet customers.

The FCC said it would not allow LightSquared to launch its business until interference issues are resolved. Spokesman Neil Grace said the agency will review the report, adding: “Our nation cannot afford to let spectrum go underutilized. America’s economic growth and global competitiveness are on the line.”

There is much at stake. Falcone put $3 billion into the venture through his Harbinger Capital fund. The creation of a mobile broadband satellite network would turn the investor into a wireless industry competitor with a national footprint rivaled only by Verizon, AT&T, Sprint Nextel and T-Mobile.

That rivalry would be welcome news to the FCC, which has pushed for more competition in the wireless industry.