GPS industry representatives went before Congress today to pan a proposal by
LightSquared to reduce interference between LightSquared’s planned 4G cellular
network and GPS receives used by consumers and industry.
offered to limit the
initial operation of its 4G LTE network to the lower part of the L-band
spectrum that it planned to use and to reduce planned base-station transmitter
power by more than 50 percent. Although LightSquared said the solution would
still, to some degree, likely affect precision GPS systems used by the aviation
and agriculture industries, it said it would work to include solutions in a report
to be delivered to the Federal Communications Commission (FCC) on July 1.
In testimony prepared for a
hearing by a House Transportation and Infrastructure Subcommittee,
representatives from GPS supplier Garmin, the Air Transport Association (ATA),
and the Aircraft Owners & Pilots Association (AOPA) contended the only way
to resolve interference would be to move LightSquare’s operation out of the L
band altogether to a band farther away from the GPS band.
LightSquared’s mitigation proposals
are either “infeasible or insufficient,” a statement by the three organizations
Referring to plans to move LightSquared
operations to a lower portion of the L band farther away from GPS frequencies
and to reduce base-station output, ATA senior VP Tom Hendricks said the plans
were “fraught with technical challenges not yet fully understood.” Regarding a
proposal to apply filters to high-precision GPS receivers, Hendricks noted that
no such filters today exist.
Even if a technical fix did
become feasible, the costs would be astronomical, Hendricks continued. “The
U.S. airline industry simply cannot afford to purchase and install it in
approximately 6,600 aircraft, which would cost billions of dollars,” he
Garmin aviation engineering VP
Philip Straub said the LightSquared solution “conveniently ignores much of the
existing user base, especially users of high precision GPS equipment.”
“With so much of the early
evidence showing that LightSquared’s proposed network would potentially
endanger nearly every flight operating in U.S. airspace, it seems evident that
no further development of this system can be allowed,” added AOPA president/CEO
For its part, the carrier has
found the lower block of frequencies to
be “largely free of interference issues with the exception of a limited number
of high-precision GPS receivers.” To “provide additional protection,” the
carrier said it would reduce maximum authorized base-station transmitter power
by more than 50 percent.
is a solution which ensures that tens of millions of GPS users won’t be
affected by LightSquared’s launch,” said LightSquared chairman/CEO Sanjiv Ahuja.