A Boeing Delta II 7925-9.5 launch vehicle launched GPS IIR-15, the second modernized GPS satellite, from Space Launch Complex 17 at Cape Canaveral Air Station, Florida, on September 25, 2006, at 2:50 PM EDT.

Known as GPS IIR-M, the modernized spacecraft are the most technologically advanced GPS satellites ever developed and are designed to provide significantly improved navigation performance for U.S. military and civilian users worldwide.

  Designated GPS IIR-15(M), this satellite will join the first modernized IIR spacecraft declared operational last year and 12 other operational Block IIR satellites currently on-orbit within the overall 29-spacecraft constellation. The Air Force is dedicating the mission to honor American POW/MIAs past and present.

  The GPS IIR-M series offers a variety of enhanced features for GPS users, such as a modernized antenna panel that provides increased signal power to receivers on the ground, two new military signals for improved accuracy, enhanced encryption and anti-jamming capabilities for the military, and a second civil signal that will provide users with an open access signal on a different frequency.

GPS

The Navstar Global Positioning System (GPS) is a constellation of orbiting satellites that provides navigation data to military and civilian users all over the world. The system is operated and controlled by the 50th Space Wing, located at Schriever Air Force Base, Colo.

GPS satellites orbit the Earth every 12 hr, emitting continuous navigation signals. With the proper equipment, users can receive these signals to calculate time, location, and velocity.

Receivers have been developed for use in aircraft, ships, and land vehicles, as well as for hand-carrying.

-> Photo: Carleton Bailie