Kalman Filtering for Relative Spacecraft Attitude and

In this paper a novel approach is developed for relative state estimation of spacecraft flying in formation. The approach uses information from an optical sensor to provide multiple line-of-sight vectors from one spacecraft to another. The line-of-sight measurements are coupled with gyro measure-ments and dynamical models in an extended Kalman filter to determine rel-ative attitude, position and gyro biases. The quaternion is used to describe the relative kinematics, while general relative orbital equations are used to describe the positional dynamics. Three different attitude formulations ar