Aging satellites might send GPSs incomplete directions
By GEOFF ZIEZULEWICZ | STARS AND STRIPES Published: July 7, 2009
The Global Positioning System that provides everything from personal navigation in private cars to military precision strike capabilities could start to falter as early as next year, according to a recent government report.
The U.S. Air Force currently controls 30 satellites used for GPS, but some of those aging spacecraft could start to fail, resulting in service disruptions by 2010, according to the Government Accountability Office. At least 24 satellites are needed to provide complete coverage.
The problem, the GAO report states, is the Air Force has not been replacing the GPS satellites quickly enough. The GAO particularly took issue with the development of a more advanced satellite system awarded to defense contracting giant Boeing in 1996. The first Boeing-produced IIF satellite is slated for launch later this year, three years late because of updated government requirements, according to Tonya Racasner, a spokeswoman with the Air Force's Space and Missile Systems Center.
"It is uncertain whether the Air Force will be able to acquire new satellites in time to maintain current GPS services without interruption," according to the report, which was released in May.
Based on the most recent satellite reliability and launch schedule data, there’s a 5 percent chance that fewer than 24 satellites will be working by 2010, according to the GAO. The figure jumps to 20 percent by 2014.
The exact impact of such a failure is hard to precisely define, the GAO report notes, as it would depend on which satellites stop operating.
"The military could see a decrease in the accuracy of precision-guided munitions that rely on GPS to strike their targets," the report states. "Disruptions in service could require military forces to use larger munitions or to use more munitions on the same target to achieve the same level of success."
While the potential effects of a decrease in GPS capability are uncertain at this point, the system’s military necessity could add weight to any repercussions, according to Loren Thompson, a defense industry consultant and member of the libertarian Lexington Institute think tank.
"GPS is sort of like the Internet," Thompson said. "The joint force has come to depend on it very heavily. So any loss of signal or reliability has huge implications."
In a news release sent after the GAO report was released, the Air Force Space Command said it had acknowledged the "potential for an availability gap" years ago and has pursued policies to mitigate that gap.
The command did not make anyone available for an interview before Stars and Stripes’ deadline. However, in an e-mailed response to Stripes’ questions, Col. Dave Buckman, command lead for the Space Command’s position, timing and navigation section, said the Air Force has been a sound steward of GPS since it went online.
"We have never failed to meet or exceed our performance commitments to civil and military users," Buckman said. "Today, we have the largest (GPS satellite) constellation and the greatest performance in history."
Army Master Sgt. Brian Schoonover has seen firsthand the benefits GPS provides to the modern-day soldier.
An Iraq veteran, Schoonover said he came into the Army decades ago, at a time when a map and compass were the primary means for navigation. GPS changed that, allowing troops to easily transmit and track positions on the ground while reducing the chance for human error.
"It’s an invaluable tool," said Schoonover, now part of Baumholder, Germany’s 2nd Brigade, 1st Armored Division. "Knowing the location of assets on a battlefield is absolutely critical to controlling a fight."
Other services, such as automobile navigation systems and tracking devices for pets, also would be affected. Although, at least one company that relies on GPS satellites is not worried.
"We are confident that the United States Air Force will be meeting their goals with the Global Positioning System, and at a minimum maintain the current level we as a nation have grown to rely upon," David Meyer, executive vice president of PROCON, Inc., said in a company news release. PROCON provides "location-based services" including PetSafe and GoldStar GPS. "GPS will not go down."
If some GPS satellites started to fail, putting the number of operational satellites below the prescribed minimum of 24, commercial and military users would likely see less detailed coverage, according to Dr. Peter Hollingsworth, a lecturer at the University of Manchester’s School of Mechanical, Aerospace and Civil Engineering in England.
The GAO report is basically calling for better oversight of the program, Hollingsworth said.
"If I was an airline operations planner or a military planner, yes, I would be concerned," he said. "Is this something the public needs to be absolutely worried about today? Probably not. But it’s something that needs an eye kept on it."
Loss of GPS signal strength or precision could affect navigation aids, targeting devices or timing systems, Thompson said. But there are other effects as well.
"People don’t view this as a crisis but they consider it to be an embarrassment and an operational problem," Thompson said. "It once again underscores doubts whether the Air Force is being a good shepherd of the military space mission."
GPS satellites are either replaced or upgraded over time as technology develops. The system went online in 1995, though the program had been in development since the 1970s.
The U.S. government provides GPS service free of charge and plans to invest more than $5.8 billion in the system over the next five years, the GAO report states.