Debate heats up over cancellation of GPS backup system

The same day the that the Obama administration confirmed it planned to cancel a GPS backup system, the Government Accountability Office issued a report warning that delays in launching new satellites could imperil the performance of the navigational system.

In his budget issued on May 7, President Obama recommended killing the Long-Range Navigation System, or Loran-C, which the Coast Guard operates. The administration argued the government should not fund the system because it is obsolete technology, and the United States no longer needs it because GPS has "superior capabilities."

But at a hearing of the House Committee on Oversight and Government Reform's National Security Subcommittee, GAO warned that GPS performance could start to degrade next year. Delays in the development and launch of two GPS satellites could reduce the number of satellites in orbit to below the minimum 24 that are needed to provide precise location information, Cristina Chaplain, director of acquisition and sourcing management at GAO, told the panel.

"The estimated long-term probability of maintaining a constellation of at least 24 operational satellites falls below 95 percent during fiscal year 2010 and remains below 95 percent until the end of fiscal year 2014, at times falling below 80 percent," she said.

If the number of GPS satellites drops below 24, Chaplain said, it "could have wide-ranging impacts on GPS users," including intercontinental commercial aviation, which "may have to cancel, delay or reroute flights." Cell phone enhanced 911 emergency services, which rely on GPS to locate callers, "could lose accuracy, particularly when operating in urban canyons or mountainous terrain," she added.

In addition, disruptions in service to military users could decrease the accuracy of GPS guided weapons, which would require forces to use either larger or multiple munitions on the same target to achieve the same effect as a guided missile.

Obama called for the cancellation of the program despite the Homeland Security Department's endorsement of a plan to upgrade the Loran-C system as a backup to GPS last year. The new system would be known as eLoran. "We are obviously concerned with potential problems with GPS," said Larry Orluskie, a DHS spokesman.

But "the Loran-C system was not established as a backup for GPS," he said. "Our initial survey of the critical infrastructure-key resource sector indicates wide variances in backups, redundant systems or contingency plans."

DHS plans to complete a review of GPS backup systems in June, Orluskie said.

GPS is the core of the Federal Aviation Administration's Next-Generation Air Transportation System, and the Transportation Department expects the Defense Department to operate 21 GPS satellites 98 percent of the time, which is equivalent to 24 satellites in operation 95 percent of the time, said Karen Van Dyke, acting director for positing, navigation and timing at the Research and Innovative Technology Administration at Transportation.

Defense, Transportation and DHS have developed backup systems to GPS other than eLoran, according to the president's budget. But Michael Harrison, a consultant with Aviation Management Associates in Alexandria, Va., said the administration has not defined other backup systems besides eLoran.

The government could save $36 million in fiscal 2010 and $190 million during five years if it ends the Loran-C program, according to the president's budget. But Harrison said keeping the current system in operation will provide a better value. "It makes no sense to cancel Loran, because it provides an adequate backup and timing signal at a lower cost than anything else," he said.

Any backup system other than eLoran would cost more and not have the same nationwide coverage as eLoran, Harrison argued. FAA plans to maintain land-based distance measuring equipment, which aircraft use to determine location, but he said the agency will have to upgrade 1,000 system components at a cost of $60 million.

GPS satellites also transmit precise timing signals for navigation, and FAA plans to use a networked timing system as a backup in the Next-Generation Air Transportation System's GPS-based Automatic Dependent Surveillance-Broadcast system. Harrison was unsure how much the system would cost, but said eLoran delivers a timing signal as well as GPS throughout North America.