A signal acquisition method in wideband Doppler model based on binary search
In the ultra-high dynamic and low Signal-to-Noise Ratio(SNR)communication scenarios like deep space communication,traditional signal acquisition methods suffer from inadequate dynamic range support,insufficient accuracy,and the use of a narrowband Doppler model leading to poor approximation accuracy in the received signal.A wideband Doppler model is employed to model the received signal and a chirp signal is used for Doppler estimation and timing estimation.A sampling rate adjustment method based on binary-search is proposed for the receiver to overcome the mismatch between the Doppler-stretched signal and the local signal sampling rate.The simulation results of the synchronization performance show that the proposed method using Up-Down Linear Frequency Modulation(UD-LFM)signal is capable of achieving a Doppler estimation error below 400 Hz and a timing estimation error below 60 ns under a SNR of-49 dB and a maximum Doppler frequency of 2 MHz.Compared to direct acquiring,the proposed method bears a higher acquisition accuracy and a lower SNR threshold.
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