The American Practical Navigator Chapter Eleven - Wikisource The Free Online Library
The concept led to improvement of the satellite navigation methods dates back to 1957 and the primary launch of an synthetic satellite tv for pc into orbit, Russia’s Sputnik I. Dr. William H. Guier and Dr. George C. Wieffenbach on the Applied Physics Laboratory of the Johns Hopkins University had been monitoring the well-known "beeps" transmitted by the passing satellite. They plotted the obtained indicators at exact intervals, and seen that a characteristic Doppler curve emerged. Since satellites typically observe mounted orbits, they reasoned that this curve may very well be used to describe the satellite’s orbit. They then demonstrated that they could decide all the orbital parameters for a passing satellite tv for pc by Doppler observation of a single go from a single fastened station. The Doppler shift obvious while receiving a transmission from a passing satellite proved to be an effective measuring mobile tracking gadget for establishing the satellite tv for pc orbit. Dr. Frank T. McClure, also of the Applied Physics Laboratory, reasoned in reverse: If the satellite orbit was recognized, Doppler shift measurements could possibly be used to determine one’s place on Earth.
His research in assist of this speculation earned him the primary National Aeronautics and Space Administration award for important contributions to area development. In 1958, the Applied Physics Laboratory proposed exploring the potential for an operational satellite Doppler navigation system. The Chief of Naval Operations then set forth requirements for such a system. The primary profitable launching of a prototype system satellite in April 1960 demonstrated the Doppler system’s operational feasibility. The Navy Navigation Satellite System (NAVSAT, mobile tracking gadget also known as TRANSIT) was the primary operational satellite navigation system. The system’s accuracy was higher than 0.1 nautical mile anyplace in the world, though its availability was somewhat restricted. It was used primarily for the navigation of floor ships and submarines, however it also had some applications in air navigation. It was additionally used in hydrographic surveying and geodetic position determination. The Federal Radionavigation Plan has designated the NAVigation System utilizing Timing And Ranging (NAVSTAR) Global Positioning System (GPS) as the first navigation system of the U.S.
GPS is a spaced-based radio positioning system which supplies suitably outfitted customers with highly correct place, velocity, and time data. It consists of three main segments: an area phase, a control phase, and a person segment. The space segment comprises some 24 satellites. Spacing of the satellites of their orbits is organized so that no less than 4 satellites are in view to a user at any time, anyplace on the Earth. Each satellite transmits signals on two radio frequencies, superimposed on which are navigation and system data. Included in this knowledge are predicted satellite ephemeris, atmospheric propagation correction information, satellite clock error information, and satellite health information. This phase normally consists of 21 operational satellites with three satellites orbiting as energetic spares. The satellites orbit at an altitude of 20,200 km, in six separate orbital planes, every plane inclined 55° relative to the equator.