Ambiguity removal technique for user position determination method in non-geostationary satellite system

This paper proposes a new position determination method for non-geostationary orbit (non-GSO) systems. The features of the proposed method are 1) to use only one non-GSO satellite for measurement, and 2) to resolve the ambiguity in deciding the true position out of two estimated positions, normally generated with conventional methods. The proposed method resolves the ambiguity by observing the movement of the two estimated positions, i.e. the true position and the falsely aligned position as a function of time. The validity of the proposed method has been confirmed for a medium earth orbit system by computer simulation. From the simulation results, it is verified that the proposed method effectively resolved the ambiguity when both the estimated true and falsely aligned positions exist in the coverage of the same spot beam, even for high mobility users.