: Interference to GPS/OnStar



D&Ds_STS
06-16-11, 02:19 PM
Have you seen this? http://www.gminsidenews.com/forums/f12/gm-s-onstar-asks-fcc-more-testing-falcone-s-lightsquared-103710/

Testing shows massive interference to all classes of GPS devices. The testing report was due to the FCC June 15, but LightSquared requested and received a 2 week extension.

I am Corvillac, formerly known as D&Ds_STS. Now driving '11 CTS-V sedan. My new handle post count is too low to post a link.

rjoffe
06-16-11, 03:52 PM
It's actually a very interesting issue. The GPS manufacturers have been lazy with their frequency filters because no one was utilizing the adjacent frequencies. Now someone wants to use those frequencies, but it will make just about all current civilian GPS receivers worthless in their service area.

Corvillac
06-16-11, 04:10 PM
It's actually a very interesting issue. The GPS manufacturers have been lazy with their frequency filters because no one was utilizing the adjacent frequencies. Now someone wants to use those frequencies, but it will make just about all current civilian GPS receivers worthless in their service area.

That is not the whole story. The FCC waiver changed the rules mid-game on the GPS users. The spectrum in question was reserved for satellite based services, similar to GPS. LightSquared was originally given permission to use the spectrum for a satellite service. Not a problem for GPS. Last November, Thanksgiving week, they asked for a waiver to use the same spectrum for terrestrial service. That flips the power density upside down, with LightSquared transmitting power levels a billion times that of GPS receive levels, at frequencies about 1% off the GPS L1 center.