Spacecraft attitude and line bias estimations from phase information of global positioning system signals

This paper presents an implementation of the filtering estimator for spacecraft attitude determination using global positioning system signals. The measured carrier phase difference between two antennas was used as observable. The nonlinear system was modelled using quaternion parameters which suitable for under manoeuvre operation and singularities avoidance. To cope with spacecraft dynamics, the moment of inertial tensor of spacecraft and torques generated by actuators were modelled to estimate the rate of change of angular velocity. An extra advantage of the implemented filtering estimator was that the electrical path difference (line bias) between antenna chains caused an offset error in measurements was estimated The implemented filtering estimator was testing through simulated data.