Improved Autonomous Navigation Algorithms for Dual Satellite Formations with Online Observability Assessment

Over the next decade, more and more aerospace missions are expected to be implemented using distributed satellite systems. A variety of these missions put forward the requirement of determining the respective absolute orbit and relative orbit of satellite in a formation autonomously. This paper focuses on the method of estimating the absolute and relative positions of a dual satellite formation only based on measurements of the relative position vector from one satellite to the other. A new index which can reflect observability on line is proposed and applied to autonomous navigation filtering process. Improved UKF and CKF with on-line observability evaluation were designed and used as navigation algorithms for synchronous orbit estimation of the two satellites. Several simulations have been carried out, resulting that those improved navigation algorithms can obviously improve the accuracy of the autonomous navigation system for the dual satellite formation.