Research On Position Extraction Of Laser Spot

The rapid development of science and technology has brought pressure for information congestion to modern communications networks.The new generation of space-satellite laser communications has been highly valued for its rapid and highly effective outstanding advantages and has gradually become the main direction for the future development of communications technologies.The spot position information collected by the detector is important information for guiding the satellite laser communication terminal to adjust the antenna alignment angle in real time and achieve high-precision tracking.Therefore,only get the precise position of the laser spot can be extracted to improve the accuracy of aiming,capturing and tracking,and ensure the normal operation of the entire communication system.The main research content of this paper is to improve the laser spot location accuracy.I have researched the development history and research status of satellite laser communication technology and system.At the same time,it carried out extensive research on the laser spot location extraction technology and algorithm.Summarizing the research literature,we can know that there are many factors that affect the laser spot location extraction accuracy,such as the laser incident angle,communication channel,image noise,etc.,so this article will explore the relationship between these factors and laser spot position extraction accuracy,choose the appropriate algorithm to calculate the spot position algorithm,in order to achieve the location of sub-pixel spot extraction accuracy.The specific work mainly includes the following aspects:1.The density distribution and physical characteristics of the imaging spot received by satellite laser communication terminals are analyzed in detail,The characteristics of the most commonly used and most classical heart-shaped methods and centroid methods are analyzed.These two algorithms are simple in calculation,short in computation time,and have high accuracy in calculation.Based on this,the accuracy will be further improved by the circle fitting method and the Zernike moment method.The calculation accuracy can be calculated by simulation experiments.The two algorithms have higher calculation accuracy and more stable calculation results.2.The key factors affecting the accuracy of laser spot position extraction were studied.Including the influence of the communication channel on the spot characteristics,the relationship between the laser spot energy center position and the laser size and the measurement error,and the influence of the laser incident direction on the laser spot position.At the same time,the different influences of different noises on the extraction accuracy of the spot position were analyzed.Two kinds of algorithms,adaptive median filter and threshold denoising based on wavelet transform,were used to overcome the errors.The two denoising algorithms were mathematically analyzed and used.MATLAB software adds noise to the collected spot image,studies and compares the denoising effect of these two algorithms,and points out that the adaptive median filter has a good filtering effect on random noise,and the threshold denoising based on wavelet transform can well Handle the interference caused by Gaussian noise.3.Sub-pixel subdivision algorithm is studied.Selecting a region with a large gradient of gray value gradient to interpolate not only saves platform resources,but also can effectively improve the accuracy of the algorithm.Choosing an appropriate interpolation method can reduce the calculation time based on the improvement of accuracy.Choosing the appropriate number of interpolation points can not only reduce the calculation error,but also reduce the amount of calculation.From the aspects of interpolation method,interpolation position and number of interpolation points,the simulation experiment of the interpolation algorithm was investigated,and an optimal interpolation strategy was obtained.4.A simulation experiment was carried out on the algorithm mentioned in this paper,and the relationship between the performance of the location extraction algorithm and the exposure time was explored.It can be seen that extending the exposure time can improve the signal-to-noise ratio of the system,thereby reducing the noise interference and improving the location extraction accuracy.And by processing the captured laser spot image,the extraction accuracy of the algorithm is verified.In general,this paper studies the accuracy of laser spot position extraction,and obtains good results.It is of great significance for the accurate positioning and tracking of satellite laser communication systems,which helps to ensure the normal operation of the entire communication system.