LightSquared, the proposed US LTE wholesale network, has received a setback with a government advisory board concluding that its proposed network would significantly interfere with GPS devices, reports the Wall Street Journal.

The Space-Based Positioning, Navigation and Timing (PNT) national executive committee – made up of nine federal agencies that coordinate GPS issues – wrote a letter to the US Commerce Department saying the network would interfere with GPS services and that it saw no way in which the issue could be fixed quickly.

LightSquared wants to build a national 4G wireless network that would provide wholesale broadband services to corporate customers. The airwaves used by the proposed network are close to GPS frequencies, raising concerns that the network could affect critical GPS services.

The company requires approval from the Federal Communications Commission (FCC) to start operating and the Commerce Department – which controls government airwaves – is due to present a report on the potential impact of LightSquared’s network on government agencies.

Following tests on LightSquared’s technology, the PNT national executive committee agencies concluded that LightSquared’s plans would have a harmful effect on GPS receivers. The advice given by the committee will be used by regulators to decide whether LightSquared’s plans can go ahead.

LightSquared hit back at the committee’s conclusions by saying government testing “has become unfair and shrouded from the public eye,” and that the advisory board is too close to the GPS industry to make a fair recommendation. The company has filed a complaint with the NASA Investigator General’s office about a conflict of interest within the PNT advisory board.

The company added that the power levels used in the tests were 32 times that of real-world conditions and requested the Commerce Department and FCC to re-evaluate the test results with “unbiased officials and engineers.”

At the beginning of January, US operator Sprint Nextel extended its deadline for LightSquared to receive FCC approval, a condition of a 15-year spectrum and equipment sharing deal between the two companies.