Performance Impact Of Spot Distortion To Beacon System Based On Four-quadrant Detector

Satellite laser communication is a wireless communication technology that uses laser light waves as the carrier and atmosphere as the transmission medium.It has a large channel capacity,strong confidentiality and strong anti-interference ability,as a result of which,it has good application prospects.Pointing,Acquisition and Tracking(PAT)technology is a key technology to ensure the reliability of the communication link in the satellite laser communication system.The use of different detection sensors will affect the spot positioning performance of the PAT system.When using a beacon light source with a wavelength of 1550 nm,compared with traditional detecting devices,the fourquadrant detector has high-speed response,high resolution,low noise and other significant advantages.Thus it's more and more widely used in the spot position detection system.This paper investigates the research progress of four-quadrant detectors used in satellite laser communication systems at home and abroad.Most of the research at home and abroad is focused on the spot position detection algorithm.For beacon systems that use four-quadrant detectors,this paper will focus on the analysis of the effect of aberration-induced spot distortion on the performance of the system.It studies the working principle of the four-quadrant detector,analyzes the influence of different factors on the positioning performance of the system,and analyzes the influence of the spot distortion caused by different types and sizes of aberration on the performance of the fourquadrant detector.On this basis,a new formula for calculating the spot position offset introduced by the operand is proposed to correct the effect of aberration,and then the effect of the correction is simulated.The simulation results and the conclusion of the aberration effect analysis are mutually confirmed,and shows that when the iteration step of the calculation operand chooses a smaller value,the correction rate can generally reach more than 90%.When the appropriate value of the iteration step is selected,the correction method proposed in this paper is verified to be reasonable and feasible.As a result,the influence of spot distortion introduced by the ground assembly on the positioning performance of the beacon system based on the four-quadrant detector can be greatly reduced.