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    Re: GPS Interference
    From: Gary LaPook
    Date: 2011 Sep 27, 18:06 -0700
    This is from the October 2011 issue of AOPA Pilot magazine, from the Airplane Owners and Pilots Association:

    NATIONAL

    FCC asked to halt GPS-jamming network

    Full rulemaking process urged in LightSquared case

    The Federal Communications Commission, now in possession of clear evidence that a proposed mobile communications network jams GPS signals, should recall approval it granted network venture LightSquared, and begin a full rulemaking process in the case, said AOPA and the General Aviation Manufacturers Association (GAMA).

    The two associations, participants in a technical working group in the case through their representatives on the Program Management Committee of RTCA Inc., recently filed formal comments with the FCC. AOPA and GAMA strongly urged the FCC to recall the waiver granted in January to LightSquared conditional on tests and solutions to now-confirmed interference with GPS. LightSquared has “entirely failed” to solve interference problems, which threaten the future of a GPS-based air traffic system—and no technology exists to provide a remedy, they said in the joint filing.

    “The evidence is clear: LightSquared’s proposal puts the entire GPS system at risk,” said AOPA President Craig Fuller. “Study after study has shown that LightSquared’s plan is simply ‘incompatible’ with GPS. At the same time, the company’s proposed solutions rely heavily on technology that doesn’t exist. That’s why we are joining with GAMA to ask the FCC to revoke LightSquared’s waiver immediately, and to begin a rulemaking process that will protect the integrity of the GPS system into the future.”

    After the adverse test results emerged, LightSquared acknowledged the problems but blamed the present conflict on past GPS designs. The company publicized an offer of a six-month “standstill” period—while also insisting that modification of existing and future GPS receivers to filter out extraneous signals be part of the solution.

    LightSquared “assumes that suitable filters will soon become available. No evidence suggests that will be the case. Absolutely no filters exist today that can reliably protect GPS from LightSquared interference,” wrote Melissa Rudinger, AOPA senior vice president of government affairs, and Jens Hennig, GAMA vice president of operations. The FAA’s impact statement concluded that “no realistic chance exists that a suitable interference solution can be invented, qualified for aviation use, and certified for installation across the fleet in less than 10 to 15 years.”



    gl



    --- On Mon, 9/19/11, Richard M. Pisko <rmpisko1{at}telus.net> wrote:

    From: Richard M. Pisko <rmpisko1{at}telus.net>
    Subject: [NavList] Re: GPS Interference
    To: NavList@fer3.com
    Date: Monday, September 19, 2011, 11:50 AM

    On Sun, 18 Sep 2011 12:42:37 -0600, Apache Runner <apacherunner---.com> wrote:

    > I'd suspect that the problems of interference may well be in the details of
    > the construction of the transmitters in the Light-squared frequency range,
    > and receivers in the GPS - the degree of sensitivity and bleed-through - so
    > the devil may lie in details like that.    Of course it doesn't mean that
    > decision making isn't prone to politics and corruption, but if the details
    > involve a question of engineering standards, the issue gets a bit more
    > cloudy.

    I had read that the initial application (approved) was for satellite phones; bought up by LightSquared and modified to all terrestrial transmission towers.  Lots of difference in the energy that reaches the ground receivers.

    --Richard . . .

    Using Opera since the"Dog" died



       
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