Design Of High Performance Lidar Ranging System Based On Pseudo Random Code Modulation

The laser ranging radar carried by the on orbit service satellite requires not only high precision,large range and strong stability,but also low power consumption,small volume and light weight.However,the existing laser radar is difficult to meet the above requirements at the same time.According to the special requirements of spaceborne lidar,a high-performance lidar ranging system is designed to meet the ranging requirements of satellite in orbit service.The main research work is as follows:(1)Aiming at the expected index of spaceborne laser ranging radar,after comparing the advantages and disadvantages of common laser radar ranging methods,the ranging method combining pseudo-random code modulation technology and photon accumulation technology is selected,and the overall scheme of the system is designed.(2)According to the overall scheme,the laser modulation system and laser receiving system are designed.The laser modulation system adapts the driving standard of the optical modulator by dynamically adjusting the pseudo-random code signal,which effectively improves the extinction ratio of the emitted laser.The laser receiving system includes signal shaping circuit and photon detector designed by Geiger mode APD,which ensures the detection sensitivity of photon level echo signal.(3)The software system of laser ranging radar is designed and implemented.The pseudo-random code of the modulated laser is generated by FPGA programming.At the same time,the photon accumulation and echo signal recovery are carried out by using the double port Bram ping-pong operation,which effectively improves the data processing efficiency and the signal-to-noise ratio of the system.The host computer uses the ranging results of FPGA to construct the echo probability model,and combines the centroid algorithm to optimize the operation,which greatly improves the ranging accuracy.According to the hardware system design and software system design of laser radar,the principle prototype is developed.When the ranging experiment is carried out outdoors,the error of ranging results at 100 m is not more than 2cm,and the range resolution accuracy of moving targets at 14833.776 m is better than 0.1m,which reaches the expected index of spaceborne lidar,and verifies the performance advantages of this lidar system.