Study On The Method Of Improving The Precision Locating In Laser Spots Using In Inter-statellite Laser Communication

During the Laser Communication Satellite communications process, in order to achieve the establishment and maintenance, PAT(Pointing, acquisition,and tracking)system must be able to in real time, to accurately determine the centroid position spot image to accurately calculate its standard deviation of the position, and then to correct this error by the controller, the beam pointing at each other correctly. Therefore, the exact measurement spot centroid position is important satellite optical communication reliability guarantee. However, due to the limitations of CCD imaging resolution, the spot image resolution is always limited, and the image captured by the CCD is actually a number of discrete points, this paper aims to image processing method and mathematical algorithms in software way discrete points subdivision, even to the extent of continuous, so that the positioning accuracy of the centroid of the spot can be further improved.The method of this study to explore the basic idea is to use two-dimensional Gaussian function of discrete matrix obtained instead of the gray spot gray image matrix.The center can be obtained from the Gaussian spot centroid. And then use the image processing method(interpolation) for spot image processing, image spot after computing the centroid and centroid contrast obtained with the theoretical error. By comparing the size of the error of different methods to obtain the best methods and strategies as well as validation of the method.Pinpoint spot the centroid method is finally obtained by this topic is that according to the conventional image processing method based on the interpolation method,according to the characteristics of Gaussian spot divided the Spot image based on gradient(GDI methods). And in the divided region using different interpolation points and different interpolation methods. Get the best interpolation Policy by calculated and compared with the centroid error. And later make improvements on the basis of the traditional gray centroid method. The divided regions squared weighted to reflect the weight characteristics of Gaussian spot near the center, this is Divided Squared Weighting methods(DSW).The method proposed in this paper, the use of matlab simulation experiments. The GDI method proposed in this article are significantly improved compared with overallrelatively simple linear interpolation. This is because the Gaussian distribution function value is non-uniform changes, This also led after the image of the overall interpolation the improvement of positioning accuracy is not much. And the GDI method have a good solution to this problem. Using DSW algorithm to calculate the spot image which conducted by GDI methods, the DSW algorithm, compared with conventional centroid algorithm, Squared Weighting to the divided regions(according to GDI method). The purpose is that to reflects the gray value of pixel near the center spot, in order to meet the characteristics of the Gaussian spot gray value by Gaussian distribution.This article is designed to capture a spot in the simulation, using helium-neon laser as a laser light source, analog capture spot laser communication process. Through simulation experiments validate the acquired spot using this algorithm. The method of determining the accuracy, timeliness, stability. And through simulation experiments,segmentation squared weighting algorithm background light as well to some extent.