An integrated Relative Navigation system using GPS/VISNAV for ultra-close spacecraft formation flying

To improve the accuracy and better fault-tolerant performance for ultra-close spacecraft formation flying, a Global Position System (GPS)/Vision based Navigation (VISNAV) integrated Relative Navigation and Attitude Determination (RNAD) approach was presented in this paper. Onboard GPS was used for RNAD for formation spacecraft by multi-antennas configuration. The same RNAD information was also achieved by VISNAV system separately by using multiple line-of-sight vectors observations from spacecraft to another. Optimal fusion of RNAD information from both GPS/VISNAV subsystems was achieved by a Federal Kalman Filter (FKF) architecture. Simulation results provided later indicate that the integrated system can provide a total improvement of relative navigation and attitude estimation performance in accuracy and fault-tolerant.