New Wireless Tech Jams GPS

New Wireless Tech Jams GPS

UPDATED: With LightSquared Company Comments

ORLANDO– Deputy Defense Secretary Bll Lynn has raised concerns with the Federal Communications Commission about a new technology used by a company called LightSquared that jams both military and civilian GPS signals. The Federal Aviation Administration shares the Pentagon’s worries.

Air Force Gen. William Shelton, head of Air Force Space Command, disclosed the Pentagon and FAA’s concerns at the Air Force Association winter conference today. Shelton told reporters that an unnamed GPS company had tested its gear and found that LightSquared’s towers built to generate a 4G wireless network completely jammed reception. The FCC recently granted a conditional license to the company to begin building its network using L-band spectrum, “right next to” the GPS signal, Shelton said. The conditional license requires that Light Squared prove it does not jam other signals. The company would operate only in the United States.


The FCC has told the company to work with the federal government and the GPS industry in a working group to find answers to the jamming problems. The members and goals of the working group are to be presented to the FCC by Feb. 25.

The technical problem is that the GPS signal is weak and diffuse as it comes to Earth from satellites and the new technology overwhelms it, the general said. For example, a plane flying near one of the thousands of towers Light Squared plans to build would lose the GPS signal guiding it within 12 miles of a company tower. Since the FAA plans to phase in a GPS-based air traffic control system, that could be disastrous for the nation’s civil aviation. Of course, military aircraft would face the same problems.

However, Jeff Carlisle, LightSquared’s executive vice president for regulatory affairs, said his company has “absolutely no interest in interfering with GPS.” He said the company has designed sophisticated filters to prevent jamming those GPS receivers. He believes that the test to which Shelton referred was performed recently by the GPS giant, Garmin, on two receivers. He said Garmin performed the tests using simulated filters, not the production designs his company spent $7 million designing and building to prevent interference.

Ironically, Light Squared’s press release announcing the company’s formation under new ownership last July stated it hoped to be “a disruptive force in the U.S. wireless landscape by democratizing wireless broadband services…” It certainly looks as if it might be disruptive.

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This reminds me of a similar problem in the late 1990’s when, a Navy Commander, recognizing that the government claim on the Ka– and Ku– bands was about to expire quickly reinforced the military claim on them. Commercial interests wanted these bandwidths to run GPS and the newly evolving things called cell phones. Seems someone in DoD forgot to talk to the engineers on this one. And if the commercial interests win this fight, what impact does it have on all those UAV’s we like to claim increase our force combat effectiveness?

I’ll bet China already has their orders in.

I’m not certain about the rest of the UAV’s, but I’m sure they’re rather similar to the RQ-4 in that it navigates via INS with integrated GPS updating. Should the GPS signal be lost, it’ll continue flying based on it’s programmed INS route… it just won’t be able to receive navigational updates via GPS. Given the organic nature of the battlefield, this is… problematic.

Recent aricle in aviation international news by John Sheridan stated that truckers passing by on the jersey turnpike jammed gps devices at newark Intl airport. Sounds like the gps manufacturers should spend the extra $.11 per filter when manufacturing their gps devices in their Taiwanese manufacturing plants. I guess now we know why we can’t find bin laden.…Too many truckers driving thru the mountain ranges of Pakistan jamming the gps devices of military aircraft. Comical. After 20 years in the industry you would think the gps guys would be forced to upgrade so we wouldn’t have these issues.

Want to block a JDAM? There’s an app for that…

Aircraft , flight critical, GPS filters and correlators are significantly different than handheld consumer GPS. But all of these devices are susceptible ‚to some extents, to splatter and side lobes from “bad” transmitters.

Cell towers like Lightsquared’s “CAN” easily employ very effective filters to “eliminate” these unwanted signals from nearby band allocations such as GPS.

The question is not just about sophisticated filters for CELL towers, but also the ability of other transmitters to self detect “Bad” transmissions and shut themselves down.

In the case of the truckers, they were using illegal, unregulated, amplifiers that were poorly designed & installed. These amplifiers have a long history of interfering with a wide range of wireless services over an area of several miles.

To address the very real concern over “BAD” transmitters, manufacturers of flight critical GPS antenna are quickly moving to adaptive multichannel receiver / antenna technologies that can actively “reject” “BAD” signals from one of 16–32 directions.

“The FCC has told the company to work with the federal government and the GPS industry in a working group to find answers to the jamming problems.”

Two words…Broadband-over-Powerline redux.

can you provide more info on the truckers? or what kind of amps were they using, for what purpose?

Model-T-UAV — hopefully that’s not FHSS. FHSS Radio Interception plans were just posted at Shmoocon. You can find the code and equipment to make your own on google code –looki for ‘hedyattack’

Want to get a GI unit completely lost in A-stan so they walk into an ambush? There’s an app for that too
(let’s not tell the Taliban and hopefully, someone in the Military knows how to prevent this kind of jamming.….)

The Air Force still keeps maps inside the cockpits of their jets (whether it be a fighter, bomber, tanker, etc) along with training the aircrews on how to utilize them effectively. If GPS fails, there’s still INS, if INS fails too, that’s what the paper maps are for.

I’m sure the Army is smart enough to give their soldiers paper maps and training on how to use them.

Amazing — it does not really matter that the Gov’t and industry are working to solve this — the whole point is thatit cn easily be done by a foe around the world. NOT GOOD.
As for training to use INS and the Maps — Which UAV gets that training and how well did they do on their test ?

rotfl, lmao, thanks for the grin wok3, as a fmr USMC 2833 (satcom/crypto) later BSEE who put fwd this as a proactive defense of the DC/NSI 10 yrs pre 911 it’s heartening to see the concept actually revisited, if even by accident, oh well but thx again for what alfre woodward called bob robert’s strong suit, “deviate brilliance” semper fi my friend

Trophy, Ever hear of the pathfinders, Rangers, Green Beret, Delta Force, Airborne ? You might note that each of these groups are Army and every one of us can read a map well enough to rescue a downed pilot. try a 12 mile wooded Nav and see if you end up within 50 feet of your objective, map and compass only.

It sounds like all this country is going to you know where.
From a grandma, senior citizen

Axman, I don’t know what you sound so butt-hurt about, I wasn’t slamming the Army.… I was trying to clear up any doubts about them. So yeah, I have heard of them and I do know they have their land nav training, nor do I claim to be land nav trained and so you can go piss and moan to the guy that was having doubts about the Army.

does it block both L bands though? obviously it blocks the L1 band that is approved for civilian GPS use, but what of the L2 band that is encrypted and the military swore couldn’t be jammed?

How does the govt plan on keeping this only in the US sound like what my dog does in the yard

Orders, hell I bet they already have the documents to make them…you see 60 minutes last night?

Doesn’t affect UAV’s.

They just plug a big car stereo amp inline between their CB and antenna to boost output from something like 5 watts or 20 watts to 1000 watts. Lots of rednecks back home do it because they don’t get cell phone service. “If you yell loud enough, you’ll be heard…”

Not quite..in MOST cases, truckers use amplifiers designed for HF amateur radio use (26–30 MHz frequency band)..the only problem is that harmonic frequencies (54 MHz [TV], 108 MHz [FM radio], etc.) are amplified as well and can interfere with other users if the output from either the CB radio or the amplifier isn’t filtered to pass only the desired frequency range you want to transmit on.

Time for the government to put together the real GPS experts to resolve this challenge.

Lightsquared is trying to build an LTE network on the cheap. Instead of paying for spectrum intended for LTE as other czarriers have done, it is lobbying the FCC to grant it to use its satellite frequency as cellular mobile frequency band. Even if they suceeed in resolving interference to GPS, Lightsquared should pay us taxpayers for modifying use of this spectrum resource other than originally intended.

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