LightSquared squares off against GPS worriers

The FCC refused to rescind LightSquared's licence over potential GPS interference, so now the general public is being courted in the hope of a less well-informed decision. "GPS dead zones" are threatened if LightSquared is permitted to go through with its plan to deploy LTE technology in satellite frequencies. Reports, and …

[Xpositor]

The Terrorists Solution...?

Fantastic, now terrorists can deploy their own base-stations, which they can use to make calls on AND block GPS. Great, no risk of incoming missiles whilst planning something on the phone. Perhaps Afghanistan will see the first wide-ranging deployment of this?

[TakeTheSkyRoad]

Errrr..... not really

1) To imply that you can use this companies kit to jam GPS is *politely* wrong.... I'm tempted to be impolite but resisting. I'm fairly certain that if they wanted to it could be done with basic electronic components and say by reading a book.... just pump out lots of garbage at the right frequency.

2) If someone was doing the above then it would be VERY obvious. It would also be very easy to plonk a missle right on the source of the transmission since I bet missiles exist which specialise in exactly that (general ramming, including radar).

Now go back to watching Fox

[bill 20]

Dont worry...

...If their equipment does turn out to interfere with GPS, the US military will make the necessary adjustments to the base stations using a range of fast-acting, high yield aerial tools...

[Roy Etter]

For aviation users, this is a big deal

"Garmin might have demonstrated interference is possible (pdf showing who and how), but it ranks pretty low on the things to worry about."

Err, no. Try again.

For a lot of airports, the approved IFR approach (in clouds, can't see out the window) is a WAAS GPS approach. Apparently Garmin did a test with their GNS 430W that showed that Lightsquared's proposed trsanmitter can cause the 430W to fail. And if you're on approach, this means you (at the very least) have to break off the approach and try the whole thing again... from maybe a couple hundred feet above the ground... or (at the very worst) you lose situational awareness and die.

It's also worth mentioning that the NextGen air traffic control system is pretty much going to be built on GPS - how many "ATC freakouts" do we want to deal with when a bunch of blips on the controller's screen suddenly show "no position or speed info available"

I have heard (from Lightsquared themselves) that their mitigation plan involves installing filters on affected GPS receivers. For aviation that means the filter needs to meet a TSO (that isn't written yet), be approved by the FAA, the installation probably would need to be STC'ed, and then the actual filter installed properly by an A&P mechanic. It's fair to say that there's hundreds of thousands (if not millions) of dollars in paperwork there for the TSO and various STCs, plus at least a couple hundred dollars per airplane. Who is gonna pay for that?

Cheaper stuff is great, but if they really need any part of that satellite spectrum for "a tiny fragment of its (LightSquared) traffic to be satellite-routed," then they need a new plan.

[JeffyPooh]

Adjacent Channel Interference

Even if the new transmitter is as clean as clean can be, it can still create interference within the victim receivers. If the existing receivers were not designed with this E3 environment as a requirement, then the new transmitters (no matter how clean they may be) can still create problems.

[Sly]

Test for interference

just put a GPS receiver (one of the consumer grade ones) on the outside of a base station install and see if it can find it's location. If it works all week with the LTE traffic being generated... then all is well. If not... shut down the base station and reconfigure the whiz-bang filters for another test. After that's all configured, nobody will have anything to worry about as far as GPS dead zones. people can't even get that close to most base station installs anyhow, so it would be a great way to test it.

[Anonymous Coward]

Corruption of the monetary kind

The frequencies are designated for satellite services for a reason, so what the hell is the FCC doing allowing a company to build a terrestrial only network (in effect) based on them? It's corrupt practice and about time someone followed the money on this one.

[Anonymous Coward]

Radio Astronomy?

Will this also mess up some of the near by frequencies that are used for radio astronomy?

[el-em]

most telescope arrays are in "no transmit" areas

And have explicit protection from the frequency regulator in that country. Also, sensitive arrays tend to be built in metal enclosures dozens of feet high to shield them from surrounding RF noise - after all the telescope only needs to worry about the sky, and a fairly small window of that at a time (since the planet keeps spinning!)