An Improved Relative Navigation Method with Delayed Measurements Based on the Extended Kalman Filter

In order to solve the problem of decreasing relative navigation filtering accuracy and control divergence of GNC (Guidance, Navigation, and Control) system caused by the delayed measurements in on-orbit manipulative missions, this paper analyzes the two main sources of measurements delay. On the one hand, the output data is delayed due to the time required for the relative measurement sensors processing; and on the other hand, the mismatch between the update period of the relative measurement sensors and the GNC control period causes delayed data transmission. Based on these findings, an improved relative navigation method is proposed to handle measurements delay, and its effectiveness is verified by mathematical simulations. The improved method proposed in this paper is grounded in the traditional extended Kalman filter (EKF), requiring no additional complex computations and easy to implement in practical engineering applications.