Deere & Co. has reported to the Federal Communications Commission the risk of "severe interference" on tractors using GPS systems from as far as 20 miles away from a LightSquared tower and "a complete loss of service" between four miles and 22 miles distant.
Separately, public safety officials near the testing area reported LightSquared's tower knocked out their GPS systems in some areas, according to Bill Range, New Mexico's E-911 program director.
The frequencies Lightsquare uses are located close to the frequencies used by satellite navigation systems, and GPS users—particularly the military and police—worry the company's plan to install 40,000 antennas around the country will overpower GPS signals.
The frequencies Lightsquare uses are located close to the frequencies used by satellite navigation systems, and GPS users—particularly the military and police—worry the company's plan to install 40,000 antennas around the country will overpower GPS signals.
In principle, frequency filters should work, but there also is the matter of signal strength. GPS signals are quite weak, compared to the cell tower transmissions. And filter performance will drift with temperature.
Unless LightSquared can conclusively prove it really has a durable fix, it will not get final permission to use its satellite frequencies on the ground, to support LTE service.
LightSquared's LTE breaks GPS in New Mexico trial, angers John Deere
LightSquared's LTE breaks GPS in New Mexico trial, angers John Deere
1 comment:
A Lightsquared 'fix' that allows it to continue as it currently plans to operate and still be compatible with the installed GPS receiver base would constitute a technological miracle.
Perhaps they can operate on part of their spectrum but that would limit their data throughput. They could agree to refrain from building stations near places that require clean GPS reception .. like airports .. yea!
Ultimately, another visit to the White House is their best hope. These fiascoes always occur when the politics of a technology are out of sync with the science.
--- Charlie
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