?????????CEI??GEO??λ?????????????

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RELATIVE ORBIT MONITORING OF CEO CO-LOCATED GEOSTATIONARY SATELLITES BY USING SAME BEAM CEI

CEI can receive within the same beam the downlink signals transmitted from two co-located GEOs at two receivers of a baseline simultaneously.By doing the cross-correlation for each GEO,the precise CEI differenced phase can be obtained.And then the differential CEI measurement of the two GEOs can be constructed to cancel major common errors.The principle of relative orbit determination is analyzed.The method to solve unknown phase ambiguity and its precision are investigated.It is pointed out that the strategy of enlarging the length of baseline gradually can ensure the reliability of computed phase ambiguity as well as the filter accuracy of relative orbit.EKF simulations of two co-located GEOs have proved that differential CEI-alone can be used to determine relative orbit.