A Comparison of Autonomous Navigation Methods for Earth-Moon Halo Orbits

With a renewed interest in lunar travel on the horizon, it is becoming clear that our current methods of satellite tracking for spacecraft around the Moon are unequipped to handle this increase in demand. Therefore, a reliable method of performing autonomous navigation in lunar space is required to facilitate this new interest. Many methods of performing this autonomous navigation have been devised, but little work has been done to compare these methods to one another using standardized, relevant test conditions. In this study, we compared three different methods of performing autonomous navigation in six different test cases. The methods being tested were the star occultation method, the optical navigation method, and the lunar mirror method. These six test cases were a selection of halo orbits in the Earth-Moon system (a set of sensitive orbits dependent on Earth-Moon dynamics). We simulated the true state information for each of these test cases for a period of 30 days. We also simulated the true values of the measurements that would have been obtained by each of our three methods using this same software. Then to test the methods, we propagated the initial state of each test case using an estimator equipped with one of our measurement methods under test. This was repeated for each method, for a total of 18 test results. It was found that the optical navigation method was the best performing for all six of our test cases.