LightSquared v. GPS Users: We’ll know on June 15, 2011

At the direction of the FCC on January26, 2011 (See: for all of the filings), LightSquared and the GPS Industry Council have formed a working group. The working group will conduct tests of LightSquared’s transmission system to determine whether LightSquared’s proposed filter solution will resolve the demonstrated potential for interference to GPS users within miles of each proposed LightSquared site.

The potential for LightSquared service to cause severe interference to GPS users was made clear in an ex parte teleconference presentation made on January 19, 2011 to the FCC by members of the GPS Industry Council.

Simply put, the GPS Industry Council’s testing discloses that LightSquared’s very high output power from its planned 40,000 sites, coupled with its proximity in frequency to the very weak GPS downlink band, forms a witch’s brew for catastrophic interference to GPS receivers. LightSquared’s system is to operate in the 1525-1559 MHz band, while the GPS downlink frequencies are in the 1559-1610 MHz band. You can read the ex parte notice and the presentation by clicking here.

LightSquared has stated that it take care of the potential interference to GPS users using filters. It’s unclear whether the filters are sufficient, or who would be expected to pay for the cost of the filters.

On February 25, 2011, Light squared submitted its first report to the Commission regarding its work with the GPS Industry Council. That report is linked here. The group’s next report is due on the Ides of March. The final report showing the results of the filter testing is due to the FCC on June 15, 2011.

To frame the uses and users who could be negatively affected by GPS interference, or the outright loss of GPS coverage, here’s an abbreviated list of users and uses:

Military: Locations; targeting; timing; network synchronization; stuff we don’t know about

Aviation: Precision landing systems; aircraft location; timing; network synchronization

Transportation: Vehicle location; timing; network synchronization

Local Governments E911; Vehicle location; timing; network synchronization

Industry E911; Vehicle location; timing; network synchronization; precision measurements; stuff we don’t know about

Non-Government Users Location; rescue; timing; network synchronization

Yeah, this is a big deal


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