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Wireless Networking

LightSquared Says GPS Tests Were Rigged 186

Posted by Soulskill
from the apparently-you-can-stop-the-signal dept.
itwbennett writes "Would-be cellular carrier LightSquared claims that the company's LTE network was set up to fail in GPS interference tests. 'Makers of GPS (Global Positioning System) equipment put old and incomplete GPS receivers in the test so the results would show interference, under the cover of non-disclosure agreements that prevented the public and third parties from analyzing the process,' LightSquared executives said on a conference call with reporters Wednesday morning."
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LightSquared Says GPS Tests Were Rigged

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  • by joe_frisch (1366229) on Thursday January 19, 2012 @11:25AM (#38748116)

    A lot of aircraft GPS receivers are quite old. It can cost 10-20K$ to put a certified receiver in a light aircraft, so pilots will keep their existing equipment as long as possible. Changing the requirements on interference resistance might require very expensive re-certifications of these receivers.

  • by Walking The Walk (1003312) on Thursday January 19, 2012 @11:41AM (#38748306)

    According to TFA, the vendors

    deliberately chose obsolete and niche GPS devices that would show the most interference ... The tests also included receivers that were tested without interference filters that normally would be included in a complete device for consumers

    If true, the use of units without filters may be enough to invalidate the tests. It would be similar to testing a microwave for radiation leakage, with the door removed.

  • by RogueWarrior65 (678876) on Thursday January 19, 2012 @11:44AM (#38748350)

    1) GPS manufacturers are not a direct competitor to a wireless networking company. If Verizon or AT&T were complaining they might have a case.
    2) GPS was there first.
    3) Clearly the Lightsquared hardware is spitting out a harmonic which could be fixed but would probably make the devices much more expensive to produce.
    4) Lightsquared has been trying this case in the court of public opinion by running full page newspaper ads instead of dealing with the technology issues.
    5) Lightsquared has been making huge political donations and receiving government grant funding which makes the whole thing stink like old fish.

  • by ChronoSphere (814014) on Thursday January 19, 2012 @12:06PM (#38748610) Homepage
    For surveyors, GPS basestations + roamers used for surveying are in the $10,000+ dollar range, and you don't replace them every few years.There's always going to be significant amounts of "old" (and old in terms of the 2-year churn for mobile phones) GPS equipment being used by the folks who need extremely high levels of accuracy.
  • Re:Really? (Score:0, Interesting)

    by Anonymous Coward on Thursday January 19, 2012 @12:15PM (#38748722)

    No, completely true. The LightSquared broadcast signal is over 20 MHz away, which is a huge guard band. LightSquared does not put RF energy into GPS frequencies, but rather the GPS receiver front end gathers energy. As evidence, you can refer to the fact that 0% of cellular handsets experience interference. Because these devices generate RF, they have proper GPS front end filtering and do not experience interference. So you can pick bones, but this statement falls well short of completely FALSE.

  • by AB3A (192265) on Thursday January 19, 2012 @01:23PM (#38749642) Homepage Journal

    Parent post is quite correct. The largest cost of a GPS receiver in an aircraft is NOT the electronics itself, but the installation and certification process, not to mention the database updates.

    Remember that it has to work with many other transmitters and receivers nearby, including a Mode C or Mode S radar transponder required for most metropolitan regions, a UHF (403 MHz) ELT, a pair of VHF transmitters, possibly an HF SSB radio or an old DME system, and maybe even a weather radar. --and that's just the stuff that is supposed to deliberately transmit. Receivers can radiate their local oscillators...

    The bottom line is that when you put safety of flight navigation equipment in an aircraft, it has to be tested and certified before it can be used. Lightsquared would like us to just "replace it" with something new.

    I'd like to put their executives in an airliner filled with their damned LTE phones landing on a CAT III approach on a dark and stormy night. We'll see how "rigged" those tests were.

  • Re:Really? (Score:5, Interesting)

    by kaiser423 (828989) on Thursday January 19, 2012 @01:43PM (#38749964)
    Exactly. They took relatively cheap satellite spectrum (cheaper, because you have to put satellites in orbit) and tried to get it re-purposed as ground-based spectrum, which costs billions of dollars more. It was really pretty ballsy and elegant; make your spectrum worth billions of dollars more just by filing paperwork and hoping that you slip by. The REAL kicker came in when DirectTV, and pretty much every single company that owns satellite spectrum said "what's good for the goose is good for the gander" and all filed paperwork requesting the same waivers. I mean, you can't expect them not to try and make the spectrum that they already own worth billions more. So, the FCC got flooded with all of these waivers, realized that this was going to destroy spectrum allocations across the US and cause untold disruptions as you open up massive chunks of bandwidth to high power, ground-based transmitters. We're not talking about just knocking out GPS. If LightSquared got approved, they'd have to approve other companies waivers also, and but pretty much every single service that relies on a satellite would go kaput. Pretty simple decision for the FCC to make....
  • by rahvin112 (446269) on Thursday January 19, 2012 @04:02PM (#38752154)

    They used political muscle to get a testing waiver (personally I don't see anything wrong with allowing them to prove it doesn't work). The testing waiver doesn't give them the go ahead, it gives them permission to conduct testing and IF the testing reveals no interference or a path to eliminate the interference and IF the FCC concurs that this meets the minimum requirements of the law and IF no one else detects problems they might get a full waiver to proceed.

    They didn't make it past the first IF and the military has already mobilized along with the very powerful farming interests which pretty much guarantee that regardless of their pull with the Obama administration the FCC cant' approve this. This thing would pretty much invalidate every single GPS produced before 2008 and most of the ones produced and built right up until this moment. That means the FAA suddenly doesn't have reliable navigation, the coast guard, millitary, surveyors, farmers and others can't know with precisions where they are (and most of these are critical aspects of the america economy). If the FCC allowed this forward they would get sued by every single player in the GPS world, that's not even including the fact that the military could just designate the towers as official GPS jamming systems and drop bombs on them.

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