Simulation Research on Coherent Wind Lidar Bandpass Sampling Method

A band-pass sampling method was introduced for the coherent wind radar system to solve the problems in the echo signal sampling, including the high carrier frequency, narrow bandwidth, especially several GHz echo signal of the spaceborne wind coherent radar, high sampling rate of acquisition card required with the traditional sampling method, the mutual constraints of sampling rate and resolution of acquisition card. In this paper, a simulation test was carried out, taking the acquisition data collected from 1.5 μm all-fiber coherent Doppler lidar system as the input information to do Simulink filter and band-pass sampling. Results show that, compared with the low-pass sampling, the maximum difference of sight speed inversion is about 0.5 m/s when the change of detection distance is not large; furthermore, the time complexity of data processing is decreased, and its value is the ratio of bandpass sampling frequency and low pass sampling frequency. However, the ratio of signal to noise deteriorates, the value of which is about 1~3 dB.