Radio/VISNAV integrated navigation system for autonomous spacecraft rendezvous using two-order filter

A new relative navigation and attitude determination approach was developed for autonomous spacecraft rendezvous in this paper. The approach uses multiple optical line-of-sight vectors observations from spacecraft to another combined with radio measurements. A two order kalman filter was designed to determine relative attitude and position information. The modified rodrigues parameter was used to describe the relative attitude kinematics and relative attitude dynamics were also introduced. General relative orbit equations were adopted to describe the positional dynamics. To resolve the problem of highly sensitivity with large initial errors inherent in filter, a nonlinear iteration initialization was introduced in detail. Simulation results indicate that the accurate relative attitude and position estimates can be achieved by proposed sensor/estimator approach.