During a recent hearing, members of the House Small Business Committee questioned LightSquared Inc. executives about the company's plan to build “the nation's first wholesale-only, mobile broadband network.”

A growing number of Congressional members have questioned LightSquared's proposed network, arguing that it could interfere with global positioning system (GPS) signals.

Recent test results have confirmed that use of the company's upper 10 MHz block of spectrum — not the lower block, which LightSquared now proposes to use for initial rollout of its network — interfered with GPS receivers used by the Coast Guard, NASA and the Federal Aviation Administration, and caused GPS receivers used by state police, fire, and ambulance crews to lose reception.

“This alarmed many small businesses as they could be required to replace or retrofit their current GPS device,” said Rep. Graves (R-Mo.), the committee’s chairman, in his opening statement at the hearing. “This will be an enormous cost to small businesses. Even though LightSquared has committed to spend $50 million to retrofit federal GPS devices, this does nothing for the nearly one million small businesses that are left to pay the bill that will easily cost billions of dollars.”

The company, for its part, has agreed to further reduce transmission power levels and underwrite the development of new filtering technologies to avoid interference with GPS.

When questioned, LightSquared's executive vice-president of regulatory affairs, said that “it shouldn't cost a cent” for small businesses that must retrofit high-precision GPS receivers to filter out the interference.

Developing new system

LightSquared recently entered into an agreement with Javad GNSS Inc. to develop a new system to prevent interference with GPS devices. The system can be adapted to work with high-precision GPS devices already in use by the agriculture, surveying, construction and defense industries.

However, several committee members have called for further testing of a plan by the company to use a different block of spectrum that is further away from the GPS spectrum band.

The concern is that LightSquared's project requires the company to deploy significantly more land-based stations to operate in the Mobile Satellite Services downlink band.

These base stations, which were originally intended only as a “fill in” where mobile satellite service coverage is inadequate, emit much higher power and stand to create substantially more interference with GPS operations.

Last month, the Federal Communications Commission's (FCC) International Bureau and Office of Engineering and Technology issued a public notice concurring with the National Telecommunications and Information Administration on the need for additional testing.

The NCC has been active with the Save Our GPS coalition, which is comprised of the full range of users and technology providers.

The NCC recently submitted a coalition letter to the FCC emphasizing the need to fully test new filters proposed to reduce interference, determine the cost of retrofitting existing GPS devices with the new filters and determining who will be responsible for paying for retrofits.

The NCC also co-sponsored a briefing for Congressional staff to educate them regarding the risks of moving forward with LightSquared's proposal without properly vetting their technology and suggested remedial measures.