GPS Block III
GPS Block III (previously Block IIIA) consists of the first ten GPS III satellites, which will be used to keep the Navstar Global Positioning System operational. Lockheed Martin designed, developed and manufactured the GPS III Non-Flight Satellite Testbed (GNST) and all ten Block III satellites.[7] The first satellite in the series was launched in December 2018.[8][9][10]
History[edit]
The United States' Global Positioning System (GPS) reached Full Operational Capability on 17 July 1995,[11] completing its original design goals. Advances in technology and new demands on the existing system led to the effort to modernize the GPS system. In 2000, the U.S. Congress authorized the effort, referred to as GPS III.
The project involves new ground stations and new satellites, with additional navigation signals for both civilian and military users, and aims to improve the accuracy and availability for all users.
Raytheon was awarded the Next Generation GPS Operational Control System (OCX) contract on 25 February 2010.[12]
The first satellite in the series was projected to launch in 2014,[13] but significant delays[14] pushed the launch to December 2018.[8][15] The tenth and final GPS Block III launch is projected in FY2026.[16]
Increased signal power at the Earth's surface:
Researchers from The Aerospace Corporation confirmed that the most efficient means to generate the high-power M-code signal would entail a departure from full-Earth coverage, characteristic of all the user downlink signals up until that point. Instead, a high-gain antenna would be used to produce a directional spot beam several hundred kilometers in diameter. Originally, this proposal was considered as a retrofit to the planned Block IIF satellites. Upon closer inspection, program managers realized that the addition of a large deployable antenna, combined with the changes that would be needed in the operational control segment, presented too great a challenge for the existing system design.[58]