Reston, Va. – A government
advisory board’s tests that found LightSquared’s planned 4G LTE network will
interfere with GPS receivers of all types were “rigged to ensure that most
receivers will fail,” claimed LightSquared VP Jeff Carlisle.
The advisory board, called the Positioning,
Navigation, and Timing Executive Committee (PNT EXCOM), advises the federal
government on GPS issues, but the tests were actually conducted for it by the
GPS industry, Carlisle said. GPS industry members “cherry-picked” the GPS
receivers to be tested and focused the tests mainly on “obsolete and niche
devices” that included discontinued GPS receivers and devices manufactured as
far back as 1997, he charged. The tested devices were “ringers” and don’t
reflect devices on the market today, added LightSquared VP Geoff Stern.
On top of that, the advisory board’s tests
were based on LightSquared power outputs that are 32 times greater than what
LightSquared actually plans, the company said. And the GPS industry defined
failure by an arbitrary 1dB increase in the noise floor detected by GPS
receivers even though today’s GPS receivers are designed to tolerate a 6dB
increase before a noticeable impact becomes apparent to GPS users, the company
added. “The 1dB threshold can be detected only in a lab,” and previous Federal
Communications Commission (FCC)-mandated tests conducted by the GPS industry in
partnership with LightSquared and federal agencies found that a 1dB increase in
noise “didn’t change accuracy,” Carlise contended.
LightSquared called on the FCC and National
Telecommunications and Information Administration (NTIA) to properly
review the results and move forward quickly on LightSquared’s proposal to use
its satellite-band spectrum, which is next to the GPS band, for its planned
terrestrial cellular-data network.
The NTIA has been analyzing the
results of other tests mandated by the FCC and conducted by representatives of
the federal government, GPS industry and LightSquared. Those tests were designed to
gauge whether LightSquared’s network would interfere with the operation of GPS
receivers in cellphones, car navigation systems, and other consumer-oriented
devices used for marine and outdoor recreation activities. The NTIA must
also analyze the results of separate
FCC-mandated tests planned for GPS receivers used for high-precision and timing
applications. A start date for those tests hasn’t been announced.
The Coalition to Save Our GPS, which
represents GPS industry suppliers,
contended that the FCC-mandated tests
conducted
to date found that LightSquared interfered with GPS in six of 39 cellphones and
with 20 of 29 general location/navigation receivers. The group also cast doubt
on the effectiveness of adding filters to these devices and high-precision GPS
devices.
