Research On Single Photon Laser Ranging And Large-range And High-precision Length Calibration Technology

Laser ranging technology,which shows the characteristics of high ranging accuracy,large range,good concealment and strong anti-interference ability,has widespread applications in the fields of communication,medical treatment,aerospace,surface exploration and so on.One fact is that many problems have emerged in the development of laser ranging.Aiming at the hot issues in the field of laser ranging,this thesis mainly carries out the following two aspects:1.Research on single photon laser ranging system.2.Research on large-range and high-precision length calibration technology.For the research of single photon laser ranging system,it mainly consists of two parts: software and hardware.In terms of software,m sequence is introduced to perform the pseudo-random code sequence.Then main control chip is realized by using Xilinx Virtex-7 FPGA(Field Programmable Gate Array)chip.Finally,a single photon laser ranging algorithm based on pseudo-random code modulation is proposed.For hardware design,the MAX1932 chip is utilized to be the main chip of boost circuit to realize high voltage circuit of APD(Avalanche Photodiode).The output voltage range of the circuit is 20～90V and the ripple is no more than 20 m V.Furthermore,the dead time of APD is controlled at around 55 ns through the active inhibition circuits we designed,which greatly shortens the photon detection blind area of the detector.In addition,this thesis designs the APD performance test scheme to compare the performance of different APDs,and finally selects the spatial APD as the single photon detector in the laser ranging system.Based on the software and hardware of the single photon laser ranging system realized in this thesis,desktop experiments are carried out to verify the feasibility of the scheme,and a single photon laser ranging prototype is developed.A 20 km laser ranging experiment is carried out by selecting an appropriate test site and ranging target.The 21.4km target is successfully measured in the experiment.When the average emission power of the laser is 6.5W,there is no error result in the observation period of 1 minute,and the data refresh rate is 4～5 times/s;When the average emission power of the laser is 12.6W,there is no error result in the observation period of 1 minute,and the data refresh rate is as high as 18 times/s.In terms of large-range and high-precision length calibration technology,based on the theory of optoelectronic oscillator(OEO)and phase locked loop(PLL),an optical electric hybrid system with measurement OEO loop,reference OEO loop and stable OEO loop as the core is designed and built in this thesis.The system realizes high-precision optical fiber length measurement with alternating oscillating measurement OEO loop and reference OEO loop,and realizes long optical path stability through PLL feedback adjustment and stabilization OEO loop.The combination of the two finally realizes a high-precision length calibration system with a calibration accuracy of μm order for 10-km optical fiber.