Orbit Refinement for Doppler Removal Using Observations from Multiple Frequencies, Multiple Ground Sites, and Multiple Overpasses

Doppler frequency shifts affect signals received from satellites. This paper addresses the problem of estimating and removing Doppler offsets. Our approach is based on calculating orbital range using orbit propagation software which depends on so called "orbital elements" for inputs. We adjust the orbital elements to achieve the best base-banding and develop a time-domain metric to measure quality. We iteratively adjust orbital elements to optimize the metric. The novelty of our work is our inclusion of observations of signals received at multiple sites, at multiple frequencies, and on multiple overpasses. We show that estimating the orbital elements and predicting the satellite path on its next overpass are dramatically improved by exploiting geometric and temporal diversity available in multiple ground sites and multiple overpasses.