May 20, 2009
By AOPA ePublishing staff
Delays in the development and launch of new satellites could lead to interruptions in GPS service as early as next year, according to a U.S. Government Accountability Office (GAO) report.
The report, released in conjunction with a May 7 House of Representatives subcommittee hearing on the issue, warns that many of the older satellites currently in use could reach the end of their operational life faster than they can be replenished, resulting in a drop below the number of satellites needed to meet some GPS users’ needs.
Additionally, users could lose a potential backup for GPS: The Obama Administration’s proposed budget for fiscal year 2010 calls for the decommissioning of loran, in spite of a report recommending that the government commit to upgrading loran as a backup for GPS-based navigation.
“Over the years, AOPA has cautioned against decommissioning loran before a backup for GPS is in place,” said Craig Spence, AOPA vice president of regulatory affairs. “The news that GPS satellite failures could start as soon as 2010 underscores the need for a land-based navigational system to back up satellite-based systems.”
According to the GAO, the Air Force has encountered delays and significant technical problems that still threaten its delivery schedule for new GPS satellites. If the Air Force does not meet its schedule goals, which the GAO analysis found to be optimistic, “there will be an increased likelihood that in 2010, as old satellites begin to fail, the overall GPS constellation will fall below the number of satellites required to provide the level of GPS service that the U.S. government commits to—potentially reducing GPS service.
Gaps in GPS coverage could be especially problematic as the FAA hinges many of its NextGen modernization efforts on satellite-based technology such as automatic dependent surveillance-broadcast (ADS-B). AOPA has played a major role in the transition from ground- to space-based navigation and significantly contributed to the effort that proved ADS-B can be beneficial if implemented in a way that allows general aviation to experience affordable benefits.
The organization has been actively involved in a number of NextGen committees and working groups, including the Joint Planning and Development Office (JPDO) and the RTCA policy board. The JPDO, an interagency organization within the FAA, plans and coordinates research and development for NextGen, and the RTCA policy board sets standards for aircraft and avionics and advises the FAA on communications, navigation, surveillance, and air traffic management system issues.
In a hearing of the House Committee on Oversight and Government Reform’s national security subcommittee, the Department of Transportation submitted testimony that aviation users relying on unaugmented GPS will experience outages on a routine basis when the satellite constellation is at the government’s minimum commitment; users equipped with GPS augmented by a Wide Area Augmentation System (WAAS) will fare much better.
In the event of GPS outages, an updated version of loran could serve as a backup, according to an Independent Assessment Team (IAT) report released this year from the Institute for Defense Analyses. The report recommends that the U.S. government complete its upgrade of loran, to eLoran, which will allow it to serve as a backup for GPS. “IAT found that eLoran was the only system which could provide position, navigation, time, and frequency backup capability for all current and potential needs,” reads the report, which was sponsored by the Department of Transportation and Department of Defense.
The decommissioning of loran called for in the Obama budget is part of a cost-cutting measure, which the government says will save $36 million in 2010 and $190 million over five years. In information released by the White House Office of Management and Budget, the White House claims the nation “no longer needs this system because the federally-supported civilian Global Positioning System (GPS) has replaced it with superior capabilities,” and is not capable of serving as a GPS backup in its current state.
AOPA expressed concern in a meeting with town officials from East Hampton, New York, that restrictions proposed to curb airport noise “overwhelmingly” generated by transient commercial flights would unfairly burden traditional airport users.
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