Confirmed, Lightsquared Offers Concession To GPS Industry
December 16, 2011 - It's official. The federal
government has confirmed previously leaked reports that
tests conducted by a joint Technical Working Group show
that signals from a proposed nationwide wireless
broadband network interfered with the majority of
commercial GPS receivers tested.
LightSquared has been quick to respond with an olive
branch of sorts to the Federal Communications Commission
(FCC) and the GPS industry, but National Business
Aviation Association (NBAA) and other industry
stakeholders said the offer does not resolve concerns
A joint statement issued December 13 by the Department of Transportation and the Department of Defense confirms that ?testing did show that LightSquared signals caused harmful interference to the majority of other tested general purpose GPS receivers.?
A separate battery of tests, conducted by the Federal Aviation Administration (FAA), has shown the signals also interfered with terrain avoidance and warning systems (TAWS), which rely on GPS signals for reference to an aircraft's proximity to the ground.
In response, LightSquared executive
vice-president Jeffrey Carlisle sent a December 12 letter to FCC
Secretary Marlene H. Dortch, offering to cede authority over use
of the upper part of its allotted spectrum to the National
Executive Committee for Space-Based Positioning, Navigation and
Timing, a government organization of military and commercial
telecommunications officials. The move would effectively shut
LightSquared out from utilizing that bandwidth, which is
immediately adjacent to the spectrum used by GPS receivers.
In exchange for the concession, the company
asked for immediate access to the lower 10MHz of the spectrum
initially granted to LightSquared by the FCC in December 2010.
LightSquared claims signals utilizing this bandwidth will not
interfere with most GPS devices, provided they are fitted with
special filters. ?LightSquared recognizes as legitimate the
concern on the part of some federal agencies that, for budgetary
and planning purposes, they cannot know that GPS fixes they
deploy today will be sufficient unless they understand how the
spectrum may be used in the future,? Carlisle wrote in his
That proposal was met with wariness from the
Coalition to Save our GPS. ?LightSquared?s proposal to make use
of the upper 10 MHz subject to the approval of National PNT
Executive Committee, the government body primarily responsible
for protecting the integrity and operational effectiveness of
the GPS constellation and critical GPS uses, is a constructive
step,? the group stated. ?Unfortunately, LightSquared ties its
agreement to do that to being given the green light to proceed
full steam ahead in the lower 10 MHz, which is very premature.?
In a statement,
the National Business Aviation Association ? a founding member of the
Coalition ? noted LightSquared's proposal ?doesn't alleviate our overall
concern that its signals will still interfere with GPS signals,
potentially jeopardizing the safety of countless pilots and others who
rely on GPS for navigation. NBAA and its Members are not opposed to new
satellite technologies, as long as it is conclusively proven that they
will not interfere with GPS systems currently in use, and the newest
plan offered by LightSquared does not alleviate that concern.?
Sanjiv Ahuja announced December 7 that testing on three companies?
existing GPS receivers showed those devices, after being retrofitted
with filters, were not disrupted by LightSquared's immensely strong
signal bleeding onto bandwidth used by the weaker GPS signals. The next
day, Javad GNSS President Dr. Javad Ashjaee provided details about his
company's proposed solution to GPS interference problem: retrofitting a
series of filters to existing receivers, at a quoted cost between $300
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