FAA slows GPS plans
- By Paula Shaki Trimble
- Mar 26, 2000
The Federal Aviation Administration is pulling back the throttle on its
much-beleaguered satellite navigation program.
FAA Administrator Jane Garvey told Congress last week that it had assembled
an independent panel to review work on the the Wide-Area Augmentation System,
which will provide pilots with Global Positioning System satellite signals.
The FAA plans to slow work on the project, which, according to the Transportation
Department's inspector general, is costing the FAA almost $4 million a month.
"It means scaling back on WAAS to reduce the burn rate," Garvey said.
Slowing work on the project will allow the independent panel — made
up of experts from Stanford University, Ohio University, Mitre Corp. and
NASA's Jet Propulsion Laboratory — to assess the software problems and assemble
recommendations to fix them. Raytheon Co. also is involved in the panel's
WAAS, being developed by Raytheon, will use a network of ground stations
to refine GPS signals so that they are reliable enough for flight navigation
across the country and precision approaches to airports.
But the FAA does not expect basic navigation capability to be available
until 2002, which is two years later than the most recent schedule and more
than four years later than originally expected.
The FAA has also extended completion date for precision approach — when
visibility is limited — because of continuing software problems.
About 80 percent of the panel's work is focused on designing ionospheric
correction algorithms that correct errors in positioning data caused by
solar activity, said Per Enge, Stanford professor and co-chairman of the
WAAS Independent Performance Panel.
"We're at the peak of the solar cycle. The ionosphere won't be this
bad again for another 11 years," Enge said. Using data about the current
conditions, the panel will refine the WAAS algorithms and prove that they
are safe, he said. Raytheon's code is not far off from the desired code,
Enge stressed that the process of using an independent, open, peer-reviewed
panel is not new. The Local Area Augmentation System, a ground-based enhancement
to satellite navigation signals used on or near airports, involved an integrity
panel early in the design phase, he said.
The FAA and Raytheon stopped work early this year on WAAS after discovering
during testing that it did not meet certain safety requirements.
The WAAS integrity monitor, which alerts an aircraft pilot when a GPS
signal is not accurate, failed to detect an instance where "hazardously
misleading information" was transmitted, according to testimony from Kenneth
Mead, DOT's inspector general. Mead spoke last week before the House Appropriations
Committee's Transportation and Related Agencies Subcommittee.
The most recent WAAS delay is only one of several air traffic safety
and modernization programs that continue to rack up increased costs and
schedule slips, DOT officials told the subcommittee.
The Standard Terminal Automation Replacement System, still requires
substantial software development to improve the human-computer interface,
and the Airport Movement Area Safety System, which will help prevent runway
accidents, is still not operational after eight years of development, said
Kenneth Mead, DOT inspector general.