Patent ID: 6078284
Filing Date: 2000-06-20
Classification: G01S,H04B

Abstract:
A position determining system for a satellite communications system, comprising:a user terminal;at least two satellites with known positions and known velocities;a gateway for communicating with said user terminal through said satellites;range difference parameter determining means for determining a range difference parameter that represents a difference between (1) the distance between one of said satellites and said user terminal and (2) the distance between another of said satellites and said user terminal;range-rate difference parameter determining means for determining a range-rate difference parameter that represents a difference between (1) a relative radial velocity between one of said satellites and said user terminal and (2) a relative radial velocity between another of said satellites and said user terminal; andposition determining means for determining the position of said user terminal on the Earth's surface based on said known positions and velocities of said satellites, said range difference parameter, and said range-rate difference parameter.