Verification of Frequency and Time Offset Estimation Method for Chirp Signals in Mobile Satellite Communication System

In order to address the synchronization issues caused by Doppler shift and delay in geostationary orbit satellite communication, a synchronization method based on Chirp signals is introduced. This method designs the structure of Chirp signals based on the frequency offset and delay of geostationary orbit satellites, and performs carrier synchronization and timing synchronization simultaneously using the up-Chirp and down-Chirp algorithms. The principle of this method is elucidated in this paper, and simulation analysis is conducted. System testing and validation are carried out using the GNU Radio platform and USRP transceiver components. The Chirp signal has a sampling point of 128. When the SNR (signal-to-noise ratio) is 5 dB, the simulated error of frequency offset estimation is approximately 5 Hz, and the simulated error of delay estimation is approximately 1.65×10^-6 s. The measured error of frequency offset estimation is approximately 7.2 Hz. Through the comparison of simulations and measurements, it is demonstrated that this method effectively solves the synchronization issues in geostationary orbit satellite communication.