Research On Performance Improvement Of High-precision Laser Positioning System

High precision laser positioning technology is a kind of Angle measurement technology with laser as carrier,optical telescope as antenna,photoelectric detector as receiving device and transceiver system separation,which is widely used in manufacturing production,precision machinery,aerospace,medical equipment and other fields.With the rapid development and combination of laser technology,microelectronics technology,semiconductor technology and computer technology,high-precision laser positioning technology began to develop towards miniaturization and large field of view.The current small laser positioning system has a small volume and a narrow effective receiving area,which leads to low echo power of received signals and affects the maximum detection range of the system.Due to the large field of view design of the positioning system,the atmospheric backscattering of laser signals will enter into the receiving system and interfere with the target signal echo,resulting in positioning deviation.Atmospheric turbulence will cause the system detected by the target azimuth Angle jitter,resulting in positioning errors.The theoretical modeling of the basic working principle of miniaturized system can provide the theoretical basis for the design of practical system.The study of atmospheric backscattering can provide theoretical basis for engineering improvement.The study of atmospheric turbulence can clarify its specific impact on the system and facilitate algorithm modification.Firstly,aiming at the typical miniaturized and large-field laser positioning system,this paper establishes an analysis model and deduces the target detection theory of the laser positioning system under general circumstances.Then,three kinds of photodetectors commonly used in the system are synthetically compared,the four-quadrant detector is selected as the optical receiving device of the system,and according to the operation mechanism of the four-quadrant detector,the solution model of the centroid position of the spot is established.Then the laser positioning system error caused by atmospheric laser backscattering is analyzed.The atmospheric backscattering analysis model of laser signal is established,and the calculation expression of backscattering power is derived.Then,based on the basic working principle of the system,the formula for calculating the offset error of the speckle centroid is derived,and the MATLAB simulation analysis is carried out.In this paper,laser pulse signal is studied in time domain,and the broadening effect of backscattering on pulse signal is analyzed and deduced.Then the theory is verified by experiments and the correctness of the theoretical analysis method is proved.Finally,the system positioning error caused by atmospheric turbulence is analyzed theoretically.According to the analysis results,the method of cumulative mean value correction is proposed.Then,the field experiment was designed,and the experimental results were compared with the theoretical analysis results and the cumulative mean value method,and the two results were found to be in good agreement,which proved that the cumulative mean value method could effectively reduce the influence of atmospheric turbulence on the performance of the positioning system.