According to the characteristics of relative measurement elements in the on-orbit servicing system with multiple space robots, a non-cooperative target co-localization strategy based on distributed filters is proposed. Firstly, the mission of non-cooperative target co-localization based on multiple space robots is defined, and a co-measurement model is also established. After that, a general expression of relative dynamics of multiple space robots is derived, and a centralized co-localization filter is designed. In order to reduce the computation load of iteration process in filtering, a co-localization method based on distributed filters is proposed. The stabilities of both filters are evaluated with linear system observability theory. Finally, a real-time semi-physical simulation system is established, and the co-location strategy based on distributed filters is simulated. The high stability and accuracy of the co-localization strategy are demonstrated by simulations.
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