GPS IIF-1 Introduces a Host of New Capabilities for Users
By Global Positioning Systems Wing, SMC
/ Published November 05, 2010
LOS ANGELES AIR FORCE BASE, Calif. -- There's no satellite system that touches so many lives in so many ways around the world like the Global Positioning System. From finance to farming, from ATMs to UAVs, from rescue missions to shopping trips, GPS is the premier provider of positioning, navigation and timing services for civil and military users worldwide. The current GPS constellation has the most satellites and the greatest number of capabilities ever. GPS continues to address the growing needs of the military, civil and commercial users around the globe.
Launched on May 27, aboard a United Launch Alliance Delta IV Medium rocket, GPS IIF-1 completed three months of comprehensive on-orbit testing to validate its operations with the ground control system, other GPS satellites and a wide range of military and commercial GPS ground receivers. Since this was the first of 12 IIF space vehicles to be launched, the testing regimen was longer and more rigorous than usual.
On Aug. 25, the GPS Wing transferred Satellite Command Authority for GPS IIF SV-1 to the 2nd Space Operations Squadron at Schriever Air Force Base, Colo. The following day, the squadron announced that GPS IIF satellite (SVN-62) was set healthy.
GPS IIF-1 going operational is great news for the nearly one billion users that depend on GPS services. Not only is GPS IIF-1 joining the 30 satellites on-orbit in the GPS constellation, the most robust and capable system in the history of space, it's introducing new and enhanced capabilities for military and civil users. GPS IIF continues the modernization efforts to provide new space-based capabilities to ensure GPS remains the gold standard for positioning, navigation and timing.
Some of the key capabilities that the new GPS IIF satellites will provide:
Greater accuracy through advanced atomic clock technology
The GPS IIF series leverages advanced atomic clock technology to greatly improve precision timing, which is the heart of GPS services. These clocks have frequency standards composed of cesium and rubidium technologies that can keep time within 8 nanoseconds (8 billionths of a second) a day. On-orbit testing of GPS IIF-1 already shows excellent performance -- in some categories, the best in the constellation. Performance will improve as on-orbit adjustments continue.
Military signals more resistant to attempted jamming
Military equipment extensively uses GPS precision timing and navigation capabilities to perform missions safely and more effectively. Naturally, that makes them the targets of jamming attempts. The military signal on the GPS IIF satellites is specially formatted to counter jammers better than current GPS satellites. GPS IIF also has a variable power capability that allows operators to increase signal power to break through jamming attempts.
New civilian signal
The GPS IIF satellites carry the first operational civilian signal, L-5, a protected, high-power, wide-bandwidth signal used to assist commercial aviation activities and safety-of-life applications. Aircraft will use the signal to improve positioning and navigation accuracy and boost safety, capacity and fuel efficiency. Beyond transportation, L-5 will provide users worldwide with the most advanced civilian GPS signal that, when used with other civilian signals, can enable sub-meter accuracy and longer-range operations.
On-board reprogrammable processor with greater capability to receive updated software on orbit
Older GPS satellites have limited updating capability; the IIFs carry onboard throughput and memory margins to update both the GPS navigation system and the satellite's operating system.
Longer design life for reduced operating costs
GPS IIF satellites are designed to last 12 years on-orbit, and longer operational life means lower operating costs. The IIF satellites will form the backbone of the constellation for the next 15 to 18 years. Past system performance indicates that the satellites could likely last much longer. Approximately a dozen Boeing-built GPS IIA satellites are still in operation, some lasting two or three times longer than their original design lives.
The entire GPS constellation is controlled by the Operational Control System. OCS has had no interruptions of service or mission since activation in 2007. OCS has improved operations, increased efficiency and provided a foundation for new capabilities, such as the Selective Availability Anti-Spoofing Module, which provides security against fake satellite signals