Precise GPS relative navigation for future geodetic satellite formation flying missions

The technique of formation flying has gained much attention in the scientific community, as it is believed to be the dominant approach for future space mission to enhance the overall performance. The added advantages of formation flying over the conventional single satellite approach include improve mission reliability with backup satellites, provide stereo observation and redundancy, and reduce the mission operation cost. Many organizations have already planned to utilize such an incredible technique for their future missions, however the use of satellite formation flying is still very new and much work is need to improve and verify the needed technologies for such an approach.; There are many important technologies associated with formation flying that would make it applicable to future space mission. One of such technology is the instrument for providing precise relative navigation. Accurate relative information is crucial for controlling the configuration to prevent collision and drift. For Low Earth Orbit mission, GPS is the ideal navigation sensor as it has proven to be reliable and precise for terrestrial applications. In this research, the navigation algorithm uses a Kalman filter that incorporates the Hill equations of motion as the propagation model. Software simulation analyzes have been conducted to verify the performance in terms of accuracies and robustness during signal outage. Although the Hill equations are only a reduced dynamic model, but promising navigation performance are delivered.