Research On Four-quadrant Laser Positioning Measurement Technology

As military technology has been developing continuously,laser positioning measurement technology is widely used in fields of laser alarm,laser positioning tracking,line displaceme nt or angular displacement measurement.In this paper,in the main research background of laser warning,which belongs to the field of laser detection,a laser positioning and measureme nt system based on four-quadrant detector has been developed.For laser positioning measureme nt systems,major causes that affect measurement accuracy are the performance of the photosensitive device,the positioning algorithm and signal processing circuit,and the measurement environment.Therefore,in this paper,the causes of the detection accuracy are analyzed and modeling has been done.And then the commonly used positioning algorithms are researched and improved,and the measurement system will be implemented on the FPGA hardware.Firstly,the performance of the selected four-quadrant detector is analyzed and clarified.Then by comparing the advantages and disadvantages of the four commonly used localiza t io n algorithms through simulation,the addition and subtraction algorithm model with wider applicability is selected.At the same time,to determine the selection of the spot size,the hardware structure of the positioning measurement system is analyzed,including the design of the lens parameters,the self-gain amplification circuit and the analysis of the signal processing board.By analyzing the treating process of the photoelectric signal,we can select the signal processing method of the self-gain amplification circuit plus pulse extraction.Secondly,some factors causing errors that appear in the measurement process of the detection system are analyzed.On the basis of the traditional addition and subtraction algorit hm,it is proposed that the spot light energy is often distributed as elliptic Gaussian distribution in the actual measurement situation,meanwhile,the effect of detector dead zone and lens distortion in the field of view to the facula energy distribution is also considered.At the same time,the error of the detection system is also analyzed,including multi-source interfere nce,background light,dark current,circuit non-uniformity and measurement error caused by mechanical error.Each type of error is modeled and simulated and verified by experiments,and finally the error correction and calibration methods are obtained.Finally,a complete four-quadrant laser positioning measurement system is designed and built.Combined with the modified algorithm in this paper,it is verified by experiment that the system has a good improvement in measurement accuracy and linear range.The experiment is carried out under various il umination intensities,while the measurement accuracy and linear range of the system are not affected by the change of circuit gain,which verifies the feasibilit y of the self-gain amplifier circuit in this system.