Research On Photon Counting Laser Ranging System And Arbitrary Waveform Generation

Laser ranging is widely used in aerospace,surveying,military and other fields due to its simple principle,high reliability and long measuring distance.With the increasing demands of the special application,people have put forward higher requirements for the size,accuracy,power consumption and ranging range of the laser ranging system.Therefore,it is of vital significance to achieve a higher precision and a wider range of single photon laser ranging using a smaller size and lower power consumption.This paper implements a single photon laser ranging system based on Time-Correlated Single Photon Counting(TCSPC).Firstly,in this paper,TDC-GP22,a high-precision time to digital converter,is selected as the time to digital converter,and a high-speed and high-precision time converter is realized by designing peripheral hardware circuit and software program in combination with FPGA.The time resolution can reach 22 ps.Secondly,aiming at the problems of InGaAs/InP avalanche photodiode under free operation mode,a high voltage power module with power ripple less than 20 mV,a feedback bridge temperature control circuit,temperature control circuit based on PID algorithm and active inhibition circuits with a dead-time of 60 ns based on FPGA and high-speed FET switch have been designed.These designs improve the performance of the detector greatly.The parameters of the single photon detector are calibrated by the designed single photon detection system.And the relationship between APD parameters,temperature and bias as well as the relationship among parameters are studied.By analyzing the the result of calibration,the best working point of APD can be selected in the inflexion point with abruptness in performance.And laser ranging experiment with a distance of 5.4 km is carried out in the best working point.The experimental results verify the feasibility of the ranging scheme,and the performance of the ranging system can be improved by increasing the stacking times when the signal-to-noise ratio deteriorate.Also,in this paper,injection locking technology is used to enhance the generation of arbitrary waveform with high-order harmonics.Injection locking technology is used to amplify and enhance the high-order harmonics and even harmonics.The first and third harmonics are generated by nonlinear modulation.After adjusting the phase and amplitude of the two waveforms,rectangular wave,sawtooth wave and reversed-sawtooth wave with high-order approximate can be synthesized.Compared with the lower order waveform,the RMS error of the ideal waveform is greatly improved.