Patent Number: 6,298,238

Title: Fast user terminal position determination in a satellite communications system

Abstract: An apparatus, method, and process for quickly and accurately determining the position of a user terminal in a satellite communications system. An initial coarse estimate of the radius of the Earth at a terminal position is made. The geometry of satellites being used and the user terminal is then determined. When only one satellite is used, the satellite-user terminal geometry includes the range and range rate of the satellite with respect to the user terminal. When two satellites are used, the satellite-user terminal geometry includes the range of each satellite with respect to the user terminal. An initial position estimate is determined based on the radius and the satellite-user terminal geometry. The coarse radius estimate can then be formed into a fine estimate and the initial position estimate further refined.

Inventors: Dai; Jin (San Diego, CA)

Assignee: Qualcomm Incorporated

International Classification: G01S 5/14 (20060101); G01S 5/12 (20060101); G01S 005/02 (); H04B 007/185 ()

Expiration Date: 10/02/2018