Missile guidance

Source: Wikipedia. Pages: 56. Chapters: Active radar homing, Advanced Inertial Reference Sphere, All-aspect, Beam riding, Command guided, D-17B, D-37C, D37D, Fire-and-forget, Global Positioning System, GPS augmentation, IBM AN/FSQ-7 Combat Direction Central, Inertial navigation system, Infrared homing, Laser designator, Laser guidance, Line-of-sight (missile), MCLOS, MISTRAM, Project Pigeon, Proportional navigation, Pursuit guidance, Q-guidance, SACLOS, SAGEM Sigma 30, Semi-active radar homing, Staring array, TERCOM, TERPROM, Track-via-missile, UDOP, Wire-guided missile. Excerpt: The Global Positioning System (GPS) is a space-based satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. The system provides critical capabilities to military, civil and commercial users around the world. It is maintained by the United States government and is freely accessible to anyone with a GPS receiver. The GPS project was developed in 1973 to overcome the limitations of previous navigation systems, integrating ideas from several predecessors, including a number of classified engineering design studies from the 1960s. GPS was created and realized by the U.S. Department of Defense (DoD) and was originally run with 24 satellites. It became fully operational in 1994. Roger L. Easton is generally credited as its inventor. Advances in technology and new demands on the existing system have now led to efforts to modernize the GPS system and implement the next generation of GPS III satellites and Next Generation Operational Control System (OCX). Announcements from the Vice President and the White House in 1998 initiated these changes. In 2000, U.S. Congress authorized the modernization effort, GPS III. In addition to GPS, other systems are in use or under development. The Russian Global Navigation Satellite System (GLONASS) was developed contemporaneously with GPS, but suffered from incomplete coverage of the globe until the mid-2000s. There are also the planned European Union Galileo positioning system, Chinese Compass navigation system, and Indian Regional Navigational Satellite System. The design of GPS is based partly on similar ground-based radio-navigation systems, such as LORAN and the Decca Navigator, developed in the early 1940s and used during World War II. In 1956, the German-American physicist Friedwardt Winterberg proposed a test of general relativity (for time slowing in a strong gravitational field) usi