The Air Force satellite systems

Various operational, interim, and developmental satellite systems produced by the efforts of the U.S. Air Force are described. The Navstar Global Positioning System (GPS) is intended to provide global location information to within 52 ft and is accessed by mobile units on two L-bands simultaneously. The GPS in a finished configuration will comprise eighteen satellites in subsynchronous earth orbits of 10,900 miles. The solar-powered satellites will also supply velocity data to within 0.3 ft/sec and in three dimensions. Performance with a test array of six satellites and aircraft passively accessing the system have resulted in rendezvous within meters and approach to landing points 90% of the time into a projected 25 x 72 m box of the target. Other systems include the AFSATCOM for secure two-way communications, the Defense Satellite Communications System for worldwide DOD communications links, FLTSATCOM for the Navy, weather observation spacecraft, and NATO systems.