The Study Of High Precision Laser Ranging System

Laser ranging system has the advantage of high repetition rate, long range, high precision and small size etc. has been widely used in national defense, spaceflight, surveying and the high precision and high repetition rate pulsed laser ranging system based on FPGA and TDC-GP21 was designed and researched in this paper.In this paper, at first, the technology of time interval measurement was discussed and the method of event delay interpolation was discussed and adopted to realize the high precision time interval measurement. The second, the workflow and principle of TDC-GP21 were discussed and the time interval measurement module was designed. Further more, the time discriminator was discussed and based on the Theoretic modeling and debugging the CR-high pass timing discrimination was designed to realize the pulse shaping to reduce the drift error. At last, the period of pulse laser range was discussed, and the parallel-module according to FPGA was designed, the multilevel FSM was used to control the workflow to improve the frequency of systemThis project was according to the Time Quest to accomplish the timing constraint to improve the high frequency stability of system. Further more, the TDC-GP21 was configured to measure the external reference clock to survey the variation of external temperature and voltage and then realize the calibration and compensation to reduce the drift error and improve the precision of system. In addition, in this paper, the distance and measurement interval were measurement and the effect of internal noise unit on the measurement results was analyzed. At last, the results of experiments and nonlinear error and stability of system and were shown and analyzed.