http://news.yahoo.com/s/ap/20110406/ap_on_hi_te/us_tec_gps_threats

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.

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.

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.

That's because GPS receivers were designed to screen out low-power signals next
door, and now the government is changing the rules, said Scott Burgett, software
engineering manager with Garmin Ltd.

Thanks to Ron Gleason