NEW YORK-The United States Global Positioning System Industry Council, Washington, is opposing a plan, scheduled for a vote this week, that would permit mobile satellite systems to have some of the spectrum now allocated for GPS and the planned Global Navigation Satellite Service.
To be decided at the World Radio Conference in Geneva, “the proposal would take a portion of the spectrum currently available for GPS and reallocate it to primary MSS use,” according to the U.S. GPS Industry Council. “The plan is backed by Inmarsat interests in Europe and was made without input from the international GPS/GNSS user community.”
According to the council, the spectrum reallocation proposal, would, among other things: threaten public safety services; eliminate a portion of the only frequency band assigned to global aeronautical radio-navigation use; and impinge on spectrum that serves as the primary civilian and military GPS frequency.
Inmarsat has proposed a new mobile satellite service in the 1559-1567 MHz band that would transmit a constant signal from geostationary satellites. The global positioning system is registered internationally for the 1565-1585 MHz band.
Inmarsat has performed an analysis it said demonstrates that its new MSS proposal won’t interfere with GPS. The council said the International Civil Aviation Organization and the governments of the United States and the Russian Federation refuted those findings earlier this year. But, it added, there was no forum to discuss a follow-up rebuttal by Inmarsat and counterpoint by the ICAO that were presented to an International Telecommunication Union meeting in June. Nor has there been formal debate on the latest point and counterpoint since then, during time leading up to this week’s vote on the Inmarsat proposal, the council said.
The U.S. GPS Industry Council contends that Inmarsat failed to account for current and planned uses of the band it seeks for MSS services.
Most of the millions of GPS receivers in use “would experience interference from the proposed Inmarsat signal,” the council said. “This is due to the fact that the Inmarsat analysis contains several technical errors and does not adequately characterize the extent of the potential problem.”
The International Civil Aviation Organization is in the process of developing the Global Navigation Satellite System as the sole source worldwide to guide aircraft from their departure from an airport gate through takeoff, landing and arrival at the new airport gate. The planned aircraft guidance system will require spectrum in the same 1559-1567 MHz band Inmarsat seeks for MSS.
This band “is the only aeronautical radio-navigation spectrum available for development of [the GNSS] system,” the council said.
Additionally, the Federal Aviation Administration is working to augment the existing GPS signal so that GPS can be used to provide precision runway approach and landing guidance for civilian aircraft. “These augmentations will rely on additional signals from geostationary satellites and/or ground facilities, known as pseudolites, to provide the necessary improvement in integrity, availability and accuracy required for civil aviation applications,” the council said.
Furthermore, the council contends, the GPS system also is under review for possible use to autonomously track satellites.
“Until this study and other ongoing studies regarding sharing the 1559-1610 (MHz) band with other radio services are complete, no definitive decision can be taken regarding sharing or an allocation to other radio services in the band.”
