Models for Frequency Doppler Shift Prediction for LEO Satellites at L-Band

In low-earth-orbit (LEO) satellite communications, frequency Doppler shift (FDS) results in lower or higher received frequency than the signal initially transmitted from the satellite. To maintain high throughput and low bit error rate, FDS compensation methods are needed. Such methods rely on the accurate prediction of FDS. In this paper, we study and evaluate four models for frequency Doppler shift prediction in the LEO constellation at L-Band frequency using both simulation and experimental measurements from the Iridium NEXT constellation. Two models are from the literature and two new models are introduced here. The two new models differ from the existing models by estimating the earth's central angle using multiple factors, i.e., the slant ranges for different elevation angles and the coordinates of both the satellite and the earth station. Our simulation and experimental results confirm that the new models achieved significantly improved accuracy in various scenarios.