Research On Laser Positioning System Based On Four-quadrant Detector

Laser positioning technology is widely used in laser guidance,free space optical communication,optical tweezers technology and precision industrial inspection.With the development of modern industry and the improvement of productivity,the accuracy and linearity of the laser positioning measurement are getting higher and higher.In this paper,the system structure,signal preprocessing,localization algorithm and correction algorithm are studied and improved,and the whole positioning system is implemented on FPGA.Firstly,after comparing the three kinds of photoelectric position detectors,quadrant detector is chosen as the photoelectric position detector of positioning system.After analyzing the composition of the system,the amplification,signal acquisition and processing,power supply circuit board are designed and drawn,which provide the hardware platform for signal preprocessing and algorithm implementation.In order to obtain more accurate and effective echo signals,hardware preprocessing modules such as pseudorandom coding,gate lock,self-gain control and pulse extraction are designed.In the localization algorithm,by analyzing the influence of heterogeneity distribution of energy on the accuracy and linearity of the system,a novel algorithm for spot location based on Gaussian distribution is proposed,which improves the positioning precision and linear range.Through the error analysis of the positioning principle of the four quadrant detector,the data correction is made from the two aspects of heterogeneity and background light and dark current interference respectively,and the calibration method of the positioning system is improved.At the same time,through the error analysis of the positioning principle of the four quadrant detector,the data correction is made from the two aspects of heterogeneity and background light and dark current interference respectively,and the calibration method of the positioning system is improved.At last,a set of laser positioning experiment system based on four-quadrant detector is designed and built.The feasibility of the proposed algorithm is verified by the experimental measurement.Compared with the traditional algorithm,the linear range and positioning accuracy of the system are improved by adding only a standard normal distribution table.It is applied to the scenes with high accuracy and real-time measurement requirements.