The GPS program was approved in 1973, and a Joint Program Office (JPO) located at the Air Force Space and Missile Organization in El Segundo, California was established.
From its inception, GPS was designed to meet the radionavigation requirements of all the military services and those of civilian users as well. On February 22, 1978, the Air Force began launching experimental GPS satellites, termed Block I satellites, on Atlas F launch vehicles. After the third satellite successfully achieved orbit, testing of the system's capabilities began at Yuma Testing Grounds, Arizona. Using a portable receiver mounted in a truck moving at 80 kilometers per hour, the Air Force showed that the desired positioning accuracy of 10 meters in two dimensions was easily achievable. After tests with the first three experimental satellites proved successful, eight additional Block I satellites were launched to complete the design and testing phase of the GPS program.5 Although these satellites, designed and built by Rockwell International, were intended to have a 3-year life span, they achieved an average operational life of almost 7 years, and one of the Block I satellites was still operating as of the date of this report.
The next series of satellites, termed Block II, was designed to be fully operational. The first Block II satellite was launched aboard an Air Force Delta II rocket on February 14, 1989.6 The current GPS constellation consists of 24 Block II/IIA operational satellites, and as previously mentioned, 1 Block I experimental satellite.
The GPS JPO has done an outstanding job of developing and testing the systems and equipment for GPS, as well as acquiring the hardware and software needed to deploy the system. This excellent effort was recognized in 1994 with the award of the Collier Trophy to the JPO and several of the major contractors involved in the GPS program. 7
Responsibility for the day-to-day management of the GPS program and operation of the system continues to rest with the Department of Defense, and is carried out primarily