Abstract:

A global positioning system(GPS) Doppler frequency shift estimation method in earth centered earth fixed(ECEF) frame was proposed. A GPS Doppler model was constructed by using geometric scalar analytic approach, considering the fact that observer is not necessarily on the ground trace of the satellite. In addition to the modeling and computation of orbital angular velocity, visible window of satellite, and the maximum elevation earthcentered angle, Doppler's characterization with regard to the observing time was deduced and analyzed. Applications in real time Doppler frequency shift related parameters estimation on assisted GPS(AGPS) receiver verify the feasibility and performance of the presented method.

Key words: assisted global positioning system, Doppler characterization, earth centered ear;th fixed, characterization model