Frequency Offset Estimation of X-band Marine Radar Sampling Signal Based on Phase Difference

Due to the relative radial movement between the transmitter and receiver of marine radar, the frequency of radar sampling signal is prone to deviation, which reduces the quality of radar sampling signal. In order to ensure the effective transmission of radar signals, a frequency offset estimation method of marine radar sampling signals in X-band based on phase difference is proposed. The AD9225 chip is selected to acquire the marine radar signal, and the undersampling theorem is used to determine the marine radar signal sampling frequency, so as to prevent the radar signal from mixing. After digital down conversion processing, two baseband signals are obtained, and the phase information of the radar sampling signal is extracted. Based on the Midamble code, the frequency offset estimation program of marine radar sampling signal is designed. The frequency offset estimation result of the signal can be obtained by executing the established procedure, and the frequency offset estimation of the sampling signal of the X-band marine radar can be realized. Experimental data show that after the application of the proposed method, the minimum signal to noise ratio of radar sampling signal is 4 dB, the minimum mean square error of frequency offset estimation is 4%, and the minimum time of frequency offset estimation is 2 s, which fully confirms that the proposed method has better application performance.