Cooperative Angles-Only Relative Navigation Algorithm for Multi-Spacecraft Formation in Close-Range

Abstract

As to solve the collaborative relative navigation problem for near-circular orbiting small satellites in close-range under GNSS denied environment, a novel consensus constrained relative navigation algorithm based on the lever arm effect of the sensor offset from the spacecraft center of mass is proposed. Firstly, the orbital propagation model for the relative motion of multi-spacecraft is established based on Hill-Clohessy-Wiltshire dynamics and the line-of-sight measurement under sensor offset condition is modeled in Local Vertical Local Horizontal frame. Secondly, the consensus constraint model for the relative orbit state is constructed by introducing the geometry constraint between the spacecraft, based on which the consensus unscented Kalman filter is designed. Thirdly, the observability analysis is done and the necessary conditions of the sensor offset to make the state observable are obtained. Lastly, digital simulations are conducted to verify the proposed algorithm, where the comparison to the unconstrained case is also done. The results show that the estimated error of the relative position converges very quickly, the location error is smaller than 10 m under the condition of 10−3 rad level camera and 5 m offset.