Importance

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Abstract

A method is disclosed for uniquely determining the position of a mobile earth station in a mobile satellite communication system which employs a non-geostationary satellite with a multi-spot beams. A given point of a preknown position on the earth surface is defined as the center coordinate of a three-dimensional coordinate axis, information on the measured distance and Doppler shift amount between a mobile earth station of an unknown position and a non-geostationary satellite is used to repeat the estimation of the position of the mobile earth station a plurality of times, thereby obtaining the position of the earth station with high accuracy. Furthermore, by observing the estimated positions of the mobile earth station obtained as a plurality of solutions at proper time intervals, comparing with one another the movements of the respective estimated positions occurring with the local time proceeds and selecting the estimated position of the minimum movement, the estimated position of the mobile earth station is uniquely determined relative to its true position.

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First Claim