A New Algorithm (STAR) for Cycle Ambiguity Resolution within GPS Based Attitude Determination

Abstract

For future board autonomous navigation tasks, GPS offers the possibility to perform these tasks on board the user satellite with a single sensor, including the advantages of low weight and power consumption, small volume, complete navigation information on board and reduced ground operation costs. With the development of the algorithms for orbit and attitude determination and the receiver hadware, a great potential with significant influence on future missions and applications has arisen. Attitude determination using GPS carrier phase measurements relies on the interferometric principle. Hereby an ambiguity appears, corresponding to an interger number of carrier phase cycles of the received GPS signal. The resolution of this interger ambiguity is an important intialization process for attitude determination and serves as a starting point for further algorithms to calculate the attitude solution. This paper presents a new method for solving the cycle ambiguities, called the STAR-algorithm (Spherical Trigonometry Ambiguity Resolution). The STAR- algorithm relies purely on spherical trigonometry. Results of simulations and ground experiments have s shown that it works very successful and robust.