Funding sought for satellite navigation

Top Federal Aviation Administration and industry officials say the FAA needsan assurance for multiyear funding to enhance the Global Positioning Systemso that the agency can proceed with a revolutionary navigational systemfor aircraft.

Officials said the funding would support the development and operationof four geosatellites, which are a key link in the FAA's Wide-Area AugmentationSystem. WAAS uses a nationwide network of reference stations to monitorerrors in the raw GPS signals. GPS provides accuracy within 100 meters,and WAAS can improve that to about 7 meters. WAAS master stations wouldcollect the errors, process them and then broadcast corrections via thegeosatellites to aircraft in the same frequency band as the GPS constellation.

The FAA is using transponders on two satellites leased from Comsat Corp.for the first phase of WAAS. But Dave Peterson, director of internationalactivities for the FAA satellite navigational program office, the agencyneeds four satellites to provide the footprint needed to blanket U.S.-controlledairspace, which reaches from Hawaii and Alaska to coastal airspace off theeastern seaboard.

Funds also are needed to develop and install systems at more than 140airports, which will supplement the satellite signals for approaches duringbad weather, officials said. Both funding lines are essential to fieldingsystems needed to support the FAA's goal to make satellite navigation thesole means of guiding aircraft in U.S.-controlled airspace early in thenext century, said Daniel Salvano, acting director of the FAA's Office ofCommunication, Navigation and Surveillance Systems.

But funding for the satellites emerged as a problem when "Congress raiseda lot of alarm [about the FAA] buying satellites," Peterson said. "We neverintended to buy them." Peterson said the agency has developed an acquisitionstrategy to lease the satellites between 2002 and 2008.

Peterson said the agency still faces funding problems in the House,which has not determined if the satellite lease "is a capital lease or aservice lease.... The Senate agrees it is a service lease." Peterson didnot provide a specific figure for the satellite lease, but called it "asignificant number."

Jack Ryan, vice president of air traffic at the Air Transport Association,the trade organization for the airline industry, said the lease of the foursatellites is the most important element of the FAA's satellite navigationstrategy. He said ATA and its member airlines, which have had schedulesdisrupted this summer by problems with the air traffic control system, wouldsupport the funding in Congress. According to Ryan, the ATA said the FAAshould acquire the four satellites in 2001, years ahead of the FAA's schedule.

The FAA can mitigate the multiyear lease costs of the satellites by sharingthem with other users, reducing the costs by 15 percent to 20 percent, Petersonsaid. The FAA has reached agreement with Canada and countries in Centraland South America to develop WAAS-type systems that would span the Americas.Aviation agencies in those countries would help pay for the satellite leases.

The current WAAS architecture has 25 reference stations in the UnitedStates, and the target architecture calls for 48 stations.

However, John Britigan, WAAS program manager for WAAS contractor Raytheon Co., said he believes the participation of other countries could reduce the number of reference stations the FAA would need to build. Mexico and at least one Central American country already plan to build WAAS reference stations.

Although the evolution of the FAA satellite navigation system is more costly, more complex and will take longer than the agency envisioned in the mid-1990s, Salvano said he believes the costs and effort will have immense payoffs. "GPS augmentation is a safety initiative," he said, "it will reduce fatal accidents.... It will help eliminate controlled flight into terrain and help mitigate surface accidents."