Radio navigation

Source: Wikipedia. Pages: 108. Chapters: Global Positioning System, Decca Navigator System, LORAN, Radio fix, Error analysis for the Global Positioning System, Fuzzy locating system, Instrument landing system, VHF omnidirectional range, Amateur radio direction finding, Low-frequency radio range, Multilateration, Non-directional beacon, Radio direction finder, GPS augmentation, Automatic vehicle location, Location awareness, Microwave landing system, GEE, Area navigation, Oboe, Omega, Distance measuring equipment, Lorenz beam, Tactical air navigation system, Tracking system, Transponder landing system, Marker beacon, L-Tronics, CHAYKA, Electronic leash, AN/MRN-1, Indoor positioning system, Localizer Type Directional Aid, Course Deviation Indicator, G-H, ZOMM, LLC, AN/MRN-3, AN/CRN-2, Y-Gerät, SCR-277, Rebecca/Eureka transponding radar, Horizontal situation indicator, Fox Oring, Alpha, Difference in the depth of modulation, AN/MRN-2, AN/UPN-1, Space modulation, Space Integrated GPS/INS, Radio Orienteering in a Compact Area, Localizer performance with vertical guidance, Microwave Scanning Beam Landing System, Telefunken Kompass Sender, Victor airways, Syledis, Two-way ranging, Cambridge Bay LORAN Tower, ISO/IEC JTC1/SC31/WG5, NKR, Ice pool, Wireless triangulation, LORAN-C transmitter Johnston Island, LORAN-C transmitter George, U-TDOA, Relative bearing indicator. Excerpt: The Global Positioning System (GPS) is a space-based global navigation satellite system (GNSS) that provides location and time information in all weather and at all times and anywhere on or near the Earth when and where there is an unobstructed line of sight to four or more GPS satellites. It is maintained by the United States government and is freely accessible by 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 (USDOD) and was originally run with 24 satellites. It became fully operational in 1994. In addition to GPS, other systems are in use or under development. The Russian GLObal NAvigation Satellite System (GLONASS) was in use by the Russian military only until it was made fully available to civilians in 2007. There are also the planned Chinese Compass navigation system and the European Union's Galileo positioning 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 Friedwardt Winterberg proposed a test of general relativity using accurate atomic clocks placed in orbit in artificial satellites. To achieve accuracy requirements, GPS uses principles of general relativity to correct the satellites' atomic clocks. Additional inspiration for GPS came when the Soviet Union launched the first man-made satellite, Sputnik in 1957. A team of U.S. scientists led by Dr. Richard B. Kershner were monitoring Sputnik's radio transmissions. They discovered that, because of the Doppler effect, the frequency of the signal being transmitted by Sputnik was higher as the satellite approached, and lower as it continued away from them. They realized that because they knew their exact lo