Research Of Pulsed Laser Ranging System

This paper, based on the project of laser ranging, analyzes the advantages and disadvantages of various laser ranging methods and finally chooses the pulsed laser ranging as the implementation. The pulsed laser ranging system designed in this paper contains two parts which are short distance measurement and long distance measurement.The main topic of short distance measurement is how to improve the precision of pulsed laser ranging. This paper analyzes all kinds of influencing factors on the precision of pulsed laser ranging, and makes further research and discussion about the key technology of timing discrimination and time-interval measurement in the laser echo system. Since the time-interval measurement of TDC-GP2improved the precision of short distance measurement, four ways of measurement model has been designed, and one of them shall be selected according to the practical condition in order to get the best measuring result. In the receiving of laser pulsed echo, it is suggested to use filtering window function to receive the laser echo pulse as the positive method instead of original negative one, which also increases the interference rejection capacity of the system with the effect of the narrow band filter.Due to the difficulty of getting the echo pulse signal in the long distance measurement, weak signal extraction theory and implementation is studied in this paper. After the simulation experiment and comparative analysis of single pulse cumulate algorithm and multiple pulses coherent cumulate algorithm, the latter cumulate algorithm is chosen as the long-distance ranging algorithm and programming realized in the FPGA chip.Finally, the hardware and software platform of the system is built to carry out the experiment and the experimental data shows that the short distance measurement meets the accuracy requirements, meanwhile gives the calibration scheme of the system.