Planned 4G Service Could Cause Widespead GPS Jamming

[The Straight Story]

Planned 4G Service Could Cause Widespead GPS Jamming

LOS ANGELES (KNX 1070) — A planned nationwide 4G broadband service threatens to cause “widespread, severe GPS jamming,” according to a recent GPS industry study and reported by KNX Newsradio.

Millions of GPS units are now in our cars, boats, planes and even smartphones.

A company called Lightsquared is hoping to begin testing the service this fall using 40,000 transmission towers.

Jeffrey Carlisle, an executive vice-president at Lighsquared claims the GPS study, done by GPS manufacturer Garmin, is faulty, because the correct filters were not used. But he concedes there may be some interference to GPS signals which, in his view, may require modification to some exiting GPS units.

http://losangeles.cbslocal.com/2011/03/03/planned-4g-service-could-cause-widespead-gps-jamming/

[JHB]

1. I don't see Mr. Carlisle offering to pay for those modifications...

...but hey, it's not his problem!

[drm604]

3. Maybe the owners of GPS units can bring a class action suit. n/t

[Statistical]

4. Against the manufacturer.

A properly designed GPS unit will not be subject to interference.

A cheaply designed one lacking right filters to isolate the frequency used by GPS sat will.



GPS signal is broadcast at 1575.42Mhz, and is designed around a 10.23Mhz operating bandwith meaning something broadcating between 1570.3Mhz and 1580.5Mhz would jam the GPS signal.

LightSquared has a license to operate on a frequency of 1525 MHz to 1559 MHz. So how can it "jam" GPS. Simple the GPS receiver companies like Garmin "cheated".

Garmin and others realized that while the GPS system is designed to operate in ~1570 to 1580 Mhz some of the signal leaks out beyond those boundaries. They built receivers which scan larger ranges. Some go to 1560 to 1590 and some as far out as 1550 to 1600.

Now previously nothing uses that frequency range so they made a second huge mistake. They designed the receivers so ASSUME than anything broadcasting in 1550 to 1600 is GPS.

Soon it won't be. If your GPS receiver doesn't work it is because it is looking at the "wrong" frequencies. You should sue the entity who screwed that up with assumptions that they profited from (more accurate GPS receivers at lower cost).

[JHB]

6. Thanks for the spectrum usage indformation. n/t

[MannyGoldstein]

2. if the gpss are designed properly

Then there should be no problem.

[SoCalDem]

5. And perhaps a revival of an industry:)

:rofl:

[ProgressiveProfessor]

7. The aviation community has been up in arms about this for some time.

FCC has begun to transition aviation away from ground based navigation aids like VORs to exclusively GPS. That includes instrument approaches. Losing GPS signals at critical times could be catastrophic. The FCC should be standing firm on no bleed over, but is choosing not to address it. Very bad thing