Wireless network raises US GPS concerns

Concern has been raised in the US that a new wireless internet network will cause significant disruption to the Global Positioning System (GPS). Construction industry bodies are concerned that this could impact on surveying equipment, machine control systems and machine telematics, among other systems.

Concerns stem from an authorisation made on January 26 by the Federal Communications Commission (FCC) to a company called LightSquared to allow it to roll-out ground-based wireless internet services. The company would be using part of the electromagnetic spectrum adjacent to the frequencies used by GPS, and the concern is that LightSquared's signal would interfere with or drown-out the GPS signal.

LightSquared points out that it is working with the United States Global Positioning System Industry Council (USGIC) and that a condition of its license is to work with interested parties to identify and study and interference concerns.

However, this has not fully allayed fears, and a group of concerned industry bodies including the Association of Equipment Manufacturers (AEM) has formed the 'Coalition to save GPS'. A statement from the Coalition said, "Lightsquared's plans to build up to 40000 ground stations transmitting radio signals 1 billion times more powerful than GPS signals as received on earth could mean 40000 'dead spots' - each miles in diameter - disrupting the vitally important services GPS provides."

The coalition period is calling for various safeguards, and says that LightSquared must bear the cost of preventing interference. It also wants a 45 day consultation and public comment period following the publication of the joint LightSquared/USGIC report on interference issues on June 15.