Doppler offset analysis for satellite clock error characterization from the Starlink observations

Clock errors significantly impact the accuracy of Doppler-Based positioning in the Starlink satellite constellation. To address this, the paper introduces a novel clock error compensation model that utilizes a quadratic polynomial to account for initial offsets, drift, and aging-induced variations in satellite clocks. Allan variance and power spectral density (PSD) analyses are conducted to assess the short-term frequency stability of Starlink satellite clocks, which is found to be comparable to that of temperature-compensated crystal oscillators (TCXOs). Experimental validation shows that integrating the clock error model with Doppler shift measurements can reduce positioning errors from several kilometers to within tens of meters. These results highlight the potential of the proposed clock error compensation model and Doppler-Based positioning method for achieving precise navigation in the Starlink satellite constellation.