GPS devices are used for airplane navigation, tracking and dispatching police cars, fire trucks and ambulances, and to guide military planes, ships, armoured vehicles, weapons and troops. (Ed Andrieski/Associated Press)

A new, ultra-fast wireless internet network is threatening to overpower GPS signals across the U.S. and interfere with everything from airplanes to police cars to consumer navigation devices.

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.

Government officials pledge to block LightSquared from turning on its network as scheduled this year unless they receive assurances that GPS systems will still work.

The stakes are high not only for the GPS industry and its users, but also for those who would use LightSquared's network. In approving it, the Federal Communications Commission seeks to boost wireless competition and bring faster and cheaper internet connections to all Americans — even in remote corners of the country.

LightSquared and the FCC both insist the new network can co-exist with GPS systems. But device makers fear GPS signals will suffer the way a radio station can get drowned out by a stronger broadcast in a nearby channel.

The problem, they say, is that sensitive satellite receivers — designed to pick up relatively weak signals coming from space — could be overwhelmed when LightSquared starts sending high-power signals from as many as 40,000 transmitters on the ground using the airwaves next door.

'40,000 GPS dead spots'

"The potential impact of GPS interference is so vast, it's hard to get your head around," said Jim Kirkland, vice-president and general counsel of Trimble Navigation Ltd., which makes GPS systems.

"Think 40,000 GPS dead spots covering millions of square miles in cities and towns throughout the U.S."

One of the biggest risks is to the GPS navigation systems used by about 40 per cent of commercial and private planes. Backup systems that rely on ground-based radio signals are not as accurate and have coverage gaps.

Public-safety officials, too, are nervous about LightSquared because they rely on GPS to track and dispatch police cars, fire trucks and ambulances.

Even the Pentagon has expressed concern as it relies on GPS to guide planes, ships, armoured vehicles, weapons and troops.

LightSquared has its roots as a satellite-phone operator, so its airwaves historically have been reserved primarily for satellite communications. FCC rules adopted in 2003 allowed the company to back up those signals with ground-based wireless service, but only to fill in coverage gaps.

In January, however, the FCC gave LightSquared permission to use its airwaves for a broader, conventional wireless data network.

Although the company will continue to offer satellite service, it plans to cover at least 92 per cent of Americans by 2015 with high-power wireless signals transmitted by base stations on earth.

Until now, GPS receivers haven't had much trouble filtering out noise in the adjacent airwaves because it consisted mostly of low-power signals beamed from space. But GPS manufacturers warn that will change once there is a major ground-based broadband network.

Both LightSquared and the FCC say further testing is needed to determine the true extent of any interference.

LightSquared won't be allowed to turn on its network until the government is satisfied that any problems are addressed, FCC spokesman Rob Kenny said.

GPS filters could fix problem

Dan Hays, a consultant with the firm PRTM, insists the technical solution is straightforward: GPS devices need to include better filters to screen out the LightSquared signals.

Estimates on the costs of a fix, however, range widely.

Hays believes it will cost no more than $12 million — or 30 cents per device — to install better filters in roughly 40 million standalone GPS units made worldwide each year. Cell phones, he said, will be fine because they don't rely solely on GPS to determine location and have better filters anyway.

But Tim Farrar, a consultant with TMF Associates, insists cellphones need upgrades, too — raising the annual cost to as much as $1 billion.

Tens of billions of dollars of existing equipment may also need to be replaced, Farrar said.

GPS manufacturers insist that neither they nor their customers should have to pay.