Optimal anti-jam attitude determination using the global positioning system

This paper develops the mathematical basis for a GPS based attitude determination (AD) system that performs even in the presence of strong external interference. This is accomplished by approaching the AD problem from an antenna array viewpoint and using phase and amplitude information, vice using only phase information as in "conventional" AD systems. By redefining the array response vector used in array processing, a Maximum Likelihood Attitude Estimator (MLAE) is developed. This paper shows that the MLAE is a consistent estimator, and its performance asymptotically achieves the Cramer-Rao Bound. Simulation based performance results of the MLAE are presented for various antenna topologies and interference scenarios, showing that it offers a significant improvement over the conventional attitude determination methods.