1550 nm相干激光测风雷达微弱回波信号处理

针对激光测风雷达回波信号极其微弱,直接快速傅里叶变换(FFT)后无法得到回波信号频域幅值的问题,该文提出了嵌入现场可编程门阵列(FPGA)的数字中频信号处理方法,有效地提取了回波信号频域幅值.激光测风雷达的回波信号是相干激光脉冲信号经过空气中气溶胶后向散射的信号,由于空气中气溶胶浓度小以及激光发射功率限制,回波信号微弱...

Weak Echo Signal Processing of 1 550 nm Coherent Laser Wind Radar

Aiming at the problem that the echo of coherent laser wind lidar is very weak and the frequency domain amplitude of the echo cannot be obtained after direct fast Fourier transform(FFT), a digital intermediate frequency signal processing method embedded in field programmable gate array(FPGA) is proposed to effectively extract the frequency domain amplitude of the echo. The echo of laser wind lidar is the backscattered signal of coherent laser pulse through aerosol in the air. Due to the small aerosol concentration in the air and the limitation of laser emission power, the echo is extremely weak. Firstly, the analog signal of echo is amplified through the intermediate frequency(IF) amplifier, and then enters the analog-to-digital converter(ADC) for sampling. Then digital IF signal processing methods such as zero padding FFT and FFT spectrum accumulation are used to improve the signal-to-noise ratio of weak echo, so as to effectively identify the frequency domain amplitude of wind speed information in echo. Through the test, the stable wind speed within 2 km is obtained, and the accuracy is 0.1 m/s.