High-speed Short-pulse Laser Proximity Fuze Ranging System

Laser proximity fuze technology is very important in promoting the weapons target-injuring efficiency.Because of the light power,good quality of beam, and strong anti-jamming capability,laser makes the weapon system having the high ratio in hitting the target and plays more and more significant role in modern battle.Laser proximity fuze technology is becoming the research hotspot around the world.Thanks to short effective distance and high accuracy of laser proximity fuze, velocity and accuracy of range-finder are required severely.To the request of high speed and high accuracy of range-finder for laser proximity fuze,this dissertation takes the laser proximity fuze of aerial defence weapon ammunition as background, photoelectric conversion and signal process of high-speed close distance range-finder have been researched, meanwhile prototype experiment has been done successfully in this paper. Experiment has indicated the high-speed close-distance pulsed range-finder could be applied in laser proximity fuze of aerial defence weapon ammunition. It possesses important significance for strengthening modern national defence construction.1) The design principles of the range-finder are described in summary. The main components and their functions are introduced in brief.2) The analysis of the spectrum of the pulsed laser is given to decide the front-end's bandwidth. And studies of the Si-PIN photodiode establish the simulation model for the design. The transistor emitter-follower circuit makes itself a high efficient way to change light into electricity. The simulations and actual tests prove that the analog circuit designs could be applied in the system of high-speed pulsed laser range-finder.3) To get the target distance quickly and accurately, the laser fight time must be measured in a quick and accurate way. To solve this problem, quick range measurement technology is researched based on the method of propagation delay and working principle of FPGA(Field Programmable Gate Array) . A time measurement circuit with an accuracy of±0.4m is designed and accomplished. It could finish the whole measurement process in 150ns after receiving sampling pulse signal. This circuit could be integrated in one chip, so the area and power consumption are decreased and the anti-interference ability is strengthened. The range-finder's control and information system based on FPGA handle the fault of traditional methods, and meet the demand both on speed and accuracy.4) This prototype has successfully proceeded indoor and outfield experiments. The test result has indicated that the effective distance of range-finder is 1～2m with an accuracy of±0.4m, and it could finish measurement process in 150ns, meeting demand of high speed and high accuracy of range-finder for laser proximity fuze.