[aprssig] Terrestrial Threat to GPS Has Now Hit The Mainstream Media.

[Stephen H. Smith]

News of the terrestrial wireless broadband network that threatens to overload 
and block GPS receivers, that I posted about around a month ago has now hit the 
mainstream media.

[The issue, if you missed my original post, is that the FCC, in it's infinite 
idiocy, has authorized a terrestrial network to be built in spectrum directly 
adjacent to the 1575 MHz GPS frequency. This spectrum, previously used for 
satellite communications, will now have 10s of thousands of ground-based 
transmitters radiating signals millions of times stronger than those from 
satellites, which will cause major overloading, desensitizing or blocking of 
GPS receivers in many areas.]

AP News via Yahoo! News

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


  Planned wireless Internet network threatens GPS

By JOELLE TESSLER, AP Technology Writer Joelle Tessler, Ap Technology Writer – 
Wed Apr 6, 3:02 pm ET

WASHINGTON – 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.

"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 
percent of commercial and private planes. Backup systems that rely on 
ground-based radio signals are not as accurate and have coverage gaps. Some 
older private planes have no backup at all.

With GPS interference, a pilot "may go off course and not even realize it," 
said Chris Dancy, a spokesman for the Aircraft Owners and Pilots Association.

LightSquared's network could also undermine the Federal Aviation 
Administration's multi-billion-dollar program to upgrade the nation's 
air-traffic control system, which is based on World War II-era radar technology.

The new GPS-based system is more precise and lets planes fly more direct 
routes. That will save airlines time, money and fuel and cut pollution. It is 
also key to accommodating projected increases in airline traffic by enabling 
planes to fly safely closer together.

Public-safety officials, too, are nervous about LightSquared because they rely 
on GPS to track and dispatch police cars, fire trucks and ambulances. Many 911 
systems also use GPS to help locate people. Disruptions could delay responses 
to emergencies, said Harlin McEwen, an official with the International 
Association of Chiefs of Police.

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

LightSquared plans to compete nationally with super-fast, fourth-generation 
wireless services being rolled out by the likes of AT&T and Verizon Wireless. 
It won't sell directly to consumers, though. Instead, LightSquared will provide 
network access to companies including Leap Wireless, parent of the Cricket 
phone service, and Best Buy, which will rebrand the service under its own name.

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 too, it plans to cover at least 92 percent 
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 next door.

Both LightSquared and the FCC say further testing is needed to determine the 
true extent of any interference. The FCC is requiring LightSquared to 
participate in a study group with GPS manufacturers and users.

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

"We have every reason to resolve these concerns because we want to make sure 
there is a robust GPS system," LightSquared executive vice president Jeffrey 
Carlisle said.

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.

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.

But Hays said GPS receivers are "eavesdropping on signals outside of where they 
are supposed to be" — in LightSquared's space.

That was not a problem — until now.

Moreover, LightSquared and the FCC say the GPS industry should have been 
preparing for a ground-based network nearby since the FCC first allowed backup 
wireless systems in that space in 2003.

The real dilemma, Hays said, is this: "This is a situation where the neighbor 
built the fence too far over the property line and may not have realized it at 
the time. Now the other neighbor wants to build a pool and there is not enough 
space. So the question is: who has to pay to move the fence?"

___

Associated Press Writer Joan Lowy in Washington contributed to this report.