Contrary to recent reports, the Global Positioning System (GPS) isn’t on the verge of a failure that would leave confused motorists groping for that paper thing called a map.
Air Force Gen. C. Robert Kehler, commander of the Air Force Space Command, cleared up the confusion in comments before the Senate Armed Services Committee strategic forces subcommittee, and separately before the House Armed Services Committee strategic forces subcommittee.
He advised alarmed lawmakers to do the math: there are 30 active GPS satellites in an orbiting constellation, plus three others that can be used as spares, plus one more.
Now, compare that to the requirement of just 24 satellites needed to maintain GPS quality, with no gaps in coverage.
However, his comments came only after news stories circulated worldwide, suggesting that the GPS system might fail.
Those reports happened to come at a time when foreign systems are being assembled to compete with the American GPS: the European Galileo system is moving ahead, as are the Chinese Beidou Navigation System and the Russian GLONASS system.
“I am highly confident we will be able to sustain more than 24 satellites” for the foreseeable future, Kehler assured the House lawmakers, noting that continued functioning of the GPS system is “important to the entire world.”
The GPS system is used for purposes as prosaic as mapping a route to a friend’s home, or as critical as guiding munitions to their target. It is used to track parcel shipments, or to retrieve stolen cars.
As to how the impression was created that GPS was teetering on the brink of partial failure, Kehler pointed to a report by the Government Accountability Office (GAO).
But the author of the GAO report, Christina T. Chaplain, GAO director of acquisition and sourcing management, said news report misreported her findings, inflating the problem far beyond what she had found.
To be sure, she told the Senate panel that even if the GPS program of providing new satellites for the constellation remains on schedule, there is an 80 percent chance that the 24 minimum satellites will remain orbiting and operational at all times.
If there are delays, those odds could drop to as little as 10 percent, she said.
Gary E. Payton, deputy Air Force under secretary for space programs, appeared at the witness table with Chaplain.
He said the 30-plus satellites in space now is “a large and very robust constellation” that “gives us a little bit of breathing space” in putting more GPS satellites into orbit. That there is a looming gap is “a little bit of a mis-characterization,” Payton told the senators.
“We think we can manage” the situation, he said.
Even if some of the 30 satellites were lost for some reason, the Air Force could manage the situation by adjusting orbits of the remaining sats, according to Air Force Lt. Gen. Larry D. James, commander of the Joint Functional Component Command for Space in the U.S. Strategic Command. With 30 satellites in use, plus three spares, the Air Force is in “a very dynamic position.”
For there to be a gap in GPS navigation signal coverage, the number of satellites working would have to plunge to less than 24, he noted.
Chaplain also criticized many military space programs for being over budget, behind schedule and short on capabilities. (Please see separate story in this issue.)
One program she cited was the GPS IIF system.
On one hand, the overall GPS II system including procurement of 33 satellites is not markedly over budget. But zeroing in on the GPS IIF system, its price now is projected at $1.6 billion, or some $870 million over an original $729 million estimate. And the program is three years behind schedule, she said. While the next-generation GPS IIIA system is currently on cost, roughly, she said its “schedule is optimistic” and problems may arise.
The contractor on the program is The Boeing Co. [BA], which issued a statement responding to her findings.
“GPS IIF will deliver more capability and improved mission performance to military and civilian users,” Boeing stated. “Working very closely with the Air Force and its team, Boeing has taken aggressive steps to resolve the technical issues on IIF with a strong emphasis on mission assurance. Design changes were required to ensure performance over the satellite design life and have caused schedule delays, but these changes are in the final phase of implementation and a fully integrated satellite (SV1) has already successfully completed the thermal-vacuum test program — the most stressing system level test. SV2 was shipped to [Cape Canaveral Air Force Station, Fla.] on May 6 to perform system-level compatibility tests and serve as a risk reduction pathfinder for SV1 processing later this year.”
The program is moving ahead well, Boeing stated.
“We are on track to deliver SV1 to the Air Force later this year for the first IIF launch. The Operational Control Segment was put into service in 2007 and has been successfully flying the current GPS constellation and will also support the IIF series of satellites.”