Boeing has a long legacy with GPS, dating back to the beginning of the program in 1974. As the prime contractor on the GPS Block I, Block II, Block IIA, and Block IIF programs, Boeing has built the majority of GPS satellites launched since 1978. GPS is used to support land, sea, and airborne navigation, surveying, geophysical exploration, mapping and geodesy, vehicle location systems, aerial refueling and rendezvous, search and rescue operations, and a wide variety of additional applications. Civilian users range from commercial airlines, trucking fleets, and law enforcement agencies to farmers, fishermen and hikers. New applications are continually emerging.