Though the Air Force believes a modified radio frequency (RF) card could be the solution to its next-generation Global Positioning System (GPS) III navigation payload issues, it is still considering alternative sources to develop the payload.
Air Force Col. William Cooley, director of the service’s GPS directorate, said Friday the modified RF card being installed by prime contractor Lockheed Martin [LMT] and payload developer Exelis [XLS] would probably eliminate the signal “crosstalk,” or RF interference, that he called the crux of the challenge. Cooley added that the contractors have been wrestling with the crosstalk issue from the beginning.
“We think we have this fixed, but they have to prove we have this thing solved,” Cooley told reporters after an Air Force Association (AFA) Mitchell Institute panel held on Capitol Hill.
Cooley said the real challenge with the navigation payload is keeping timing of eight different GPS signals located in one box synchronized. To prevent RF interference, Cooley said the Air Force is considering putting absorbent material in the RF frequencies. He said the service is also considering redesigning some of the boards that are generating these signals. Compared to GPS III’s eight signals, the GPS IIF line that is in the process of being launched has seven signals, Cooley said.
A third solution being considered, Cooley said, is separating some of the RF signals and putting them in separate boxes. Cooley declined to say which solution the Air Force was leaning toward using.
“All options are on the table,” Cooley said.
Cooley said the Air Force wants a solution that will be repeatable and producible because this won’t be developed for one satellite. It will be developed for an entire fleet. Lockheed Martin is under contract for the production of the first six GPS III satellites with the first four funded under the original contract and the fifth and sixth recently fully funded by an Air Force-exercised option on Dec. 13. Lockheed Martin had previously received advanced procurement funding for long-lead components for the fifth, sixth, seventh and eighth satellites. It also received $14 million for long-lead material for GPS III-7 and GPS III-8 (Defense Daily, Feb. 3).
Air Force Space Command (AFSPC) chief Gen. William Shelton said in February the service was examining alternative sources for the navigation payload, but didn’t give a deadline for when the issue needed to be resolved. The Air Force said in February it delayed the contracted launch availability date of fourth quarter 2015, but not the launch itself, and delayed the navigation payload delivery date of “early” 2014 due to the continuing payload issues, which Shelton had mentioned as early as September. Payload delivery is now expected this summer.
These continued delays continue to rack up the costs for the Air Force, according to a GPS directorate spokeswoman, who said the service will pay for development delays. As with any cost-plus contract, the spokeswoman said the government bears the majority of risk associated with system development. In this case, she said, the GPS III development contract is a cost-plus with cost-performance incentives that include a 70/30 cost-share ratio. The spokeswoman said the Air Force pays 70 percent of the overrun cost while the remaining 30 percent is taken from the contractor’s cost incentive fee until it reaches zero. Lockheed Martin has passed the point where it can earn any cost incentive, she said.
Shelton said in February he didn’t think the delay would cause an overall impact to the GPS III constellation, citing that the Air Force has launched only four of the 12 GPS IIF series satellites it purchased. Boeing [BA] is the prime contractor for GPS IIF. The fifth and most recent GPS IIF satellite was launched Feb. 20.
Exelis was not able to respond by press time.