Patent ID: 8615056

Claim:
A differential phase shift keying demodulator comprising: an input structured to receive current data of a global navigation satellite system, the current data representing a current phasor and past data of the global navigation satellite system, the past data representing at least two past phasors; a phase differentiator structured to process the current data and reference data, the reference data representing a reference phasor, the phase differentiator further structured to provide current resulting data representing a phase difference between said current and reference phasors and past resulting data; a manager module adapted to: when the current resulting data relates to an ephemeris data set, pass either the current resulting data or a filtered value, the passing based on a quality signal representing a quality of the current resulting data; or when the current resulting data relates to non-ephemeris data, pass the current resulting data; and a reference phasor computational module configured to generate said reference data using said past data and using output data fed back from the phase differentiator.