Research On Key Technology Of Laser Positioning System Based On Four Quadrant Detector

Laser positioning technology has the advantages of high precision,high stability and high sensitivity,and has wide application prospects in laser guidance field.However,Laser positioning are susceptible to active interference from opponents in complex battlefield environments,resulting in decreased positioning accuracy or overall failure and achieving high-precision strikes on targets difficultly.Basing on the application background of laser semi-active seeker.it has been studied that the anti-interference technology and high-precision spot position detection technology in the four quadrant detector target positioning system.The main research content includes:(1)A target positioning system framework and analyzed the work tasks undertaken are constructed by each circuit module basing on the basic principles of laser positioning technology and the working principles of four quadrant detectors.At the same time,the hardware components of the system,including optical systems,power supply circuits,signal amplification circuits,and signal acquisition and processing circuits,have been designed,which provides a hardware foundation for subsequent laser positioning research.(2)The laser coding technology and time gate technology were studied and the time gate model was established in order to improve the anti-interference ability of the positioning system.And the influence of pulse interval error on laser gate setting was analyzed.the seeker is subjected to advanced synchronous interference,two probability function descriptions of wave gate admission probability mathematical models were established.The two probability function descriptions of wave gate admission probability mathematical models were established when the seeker is subjected to advanced synchronous interference,and the relationship between the probability of wave gate admission interference signal and factors such as gate width was simulated and analyzed.Based on the principle of wave gate,a bias is added to the real-time wave gate,and the advantages of setting a bias wave gate in improving the anti-interference performance of the system are further studied,providing a reference for anti-interference measures in laser guidance.(3)The performance parameters of spot detection in laser positioning were evaluated,and two equivalent models of spot energy in spot position detection were established and simulated;Based on the uniform spot equivalent model,four spot positioning algorithms were also simulated and their applicability and advantages in laser positioning were analyzed.Then a new algorithm is established and simulated by adding compensation factors to the most widely used classical algorithms.It is found that the improved algorithm can expand the linear region range during positioning effectively;A mathematical model was established for error factors in the positioning system,including the size of the spot radius,the width of the detector dark area,background light and dark current noise,and the non-uniformity of the detector.After simulation analysis,the impact of four factors on the positioning accuracy was discussed,and error correction and calibration methods were obtained.(4)A laser positioning experimental platform was built basing on the four quadrant detectors,and the calibration method of the positioning system was improved based on the error factors of background light,dark current,and detector non-uniformity.The experiment results showed that the proposed positioning improvement algorithm were expanded to 11%,and the designed calibration method corrected non-uniformity errors within 10%,which improved the positioning accuracy of the system effectively.