Table 4.

Notable milestones in the development of GPS

YearAchievement
1954The utility of space-based satellites is in review by various scientific agencies; a study is proposed to NSF
1955DoD recommends the Naval Research Laboratory Scientific Satellite Program—which became Project Vanguard
1957Soviet Union launches Sputnik I and II satellites
Attempt to launch Project Vanguard’s first satellite (TV3) is unsuccessful
1958United States launches first satellite into orbit—Explorer 1—under the direction of the Army Ballistic Missile Agency
Project Vanguard successfully launches Vanguard 1 satellite
1959Transit satellite navigation system developed at Johns Hopkins Applied Physics Laboratory
1963System 621B, a navigation system developed by Air Force, is established
1964Timation is established by the Naval Research Laboratory and led by Roger Easton
1968DoD establishes steering committee—NAVSEG (Navigation Satellite Executive Steering Group)—to coordinate satellite navigation efforts
1973In April, DoD further pushes for coordination, naming the Air Force to lead a new initiative called the Defense Navigation Satellite System (DNSS). DNSS was overseen by the Joint Program Office (JPO). NRL is still involved
In December, the NAVSTAR GPS concept is approved by the Defense System Acquisition and Review Council (DSARC)
Phase 1 of the GPS program begins; intended to confirm the concept of space-based navigation
1974First NAVSTAR satellite—Navigation Technology Satellite (NTS)—is launched. It was a refurbished Timation satellite built by the NRL. It used the first atomic clock in space—a rubidium atomic standard
NRL expands cesium clock development for use on future satellites
1977NTS-2 satellite is launched carrying first cesium atomic clock into space
1978First of 11 Block I satellites launched between 1978 and 1985
1983After a Korean plane was accidentally shot down by the Soviet Union, President Reagan announces his intentions to make GPS available to civilian aircraft for free when the system is operational
1989The U.S. Coast Guard assumes responsibility as the lead agency for the Civil GPS Service within the Department of Transportation
The first five GPS Block II satellites are launched; From 1989 to 1997, 28 satellites are launched, including the last 19 being updated versions (Block IIA)
1991First combat use of GPS is used in the Persian Gulf War, enabling U.S. military forces to validate its usefulness in the featureless Iraqi desert
1994GPS is announced as operational and integrated into the U.S. air traffic control system
FAA announces implementation of the WAAS to improve GPS integrity and availability for civil users in all phases of flight
1996Transit satellite system ceases operation on December 31 at 2359 GMT
2001-2003Combat following 9/11 attacks and during Operation Iraqi Freedom further demonstrates the precision of GPS in military conflict
2005First “modernized” GPS satellite is launched (IIR-M) that transmits a second civilian signal for enhanced performance
2008U.S. Air Force announces award to Lockheed Martin for the development and production of GPS III satellites
2010Russian GLONASS system completes constellation of 24 satellites, becomes fully operational
U.S. Air Force announces award to Raytheon to development next-generation Operation Control System (OCX)
2012BeiDou reaches regional Asia-Pacific coverage
2016The EU’s Galileo achieves Early Operational Capability with 18 satellites in orbit
Source(s):Pace (1995), Whitlock and McCaskill (2009), GPS World (2014) 

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