Research On Acquisition Probability Of Coarse-Fine Composite Technology In Satellite Laser Communication

In the whole process of satellite optical communication,acquisition is the first step to establish the link,and it is also the most important step.The success or failure of acquisition is directly related to whether the two satellites can establish the communication link.Current international are often used in the coarse at spiral scanning way to capture and often use some radar field scanning way still exist some shortcomings,is used to establish a communication link between satellite and satellite,unable to effectively meet,therefore needs to be a more suitable for two satellite communication terminal of the scans to improve the capture probability,reduce the capture time,In this paper,based on the typical coarse scanning helical scanning mode,a compound scanning technique combining coarse scanning and fine scanning is proposed,which improves the acquisition mode to a certain extent and provides a new idea for the scanning mode of satellite optical communication.Based on satellite optical communication system and PAT subsystem composition structure,working principle is analyzed,this paper introduces several kinds of typical scanning way,the rectangular scanning,rectangular spiral scan and spiral scanning,theory model of helical scanning,after get the average capture time and average acquisition probability,analyzes its advantages and disadvantages,In determining the scan-gaze after capture mode,according to the analysis of the spiral scanning way,put forward using coarse aim and finishing at combined composite scanning technology,the way is not change the trace coarse at turntable,still perform spiral scanning,at the same time give aim subsystem of sine wave,under the premise of without any increase in the scanning time,The coverage of uncertain area is improved,which provides a new idea for space laser communication.Then,the theoretical model of the scanning mode is established,the acquisition strategy is determined,and the average acquisition time and the average acquisition probability of how long the scanning is obtained.It is further analyzed and compared with the single coarse scanning method,and the advantages of the coarse and fine composite method in the scanning process are analyzed respectively from the perspective of scanning path,overlap rate and capture probability.Firstly,through the length of the two scanning paths,the total area covered by the two scanning methods can be obtained,which indirectly proves that the coverage rate of composite scanning for the uncertain region is higher.Then the coverage rates of the two for the uncertain areas were further obtained,which confirmed the previous assumption.In order to see the improvement of the acquisition probability of the composite scan more closely and intuitively,a method of finding the acquisition probability of a single resident point is used and applied to the composite scan by referring to literature,which proves that the composite scan is superior to the helical scanBased on the theoretical model of the acquisition process,the simulation of the acquisition process was carried out according to the Monte Carlo method.The effect of the combined scanning technology of coarse scanning and fine scanning was used to evaluate the performance of the acquisition.At the same time,the single coarse scanning mode was simulated and compared with the composite scanning mode.After adding the random vibration caused by the space environment and the satellite itself,the scanning trajectory deviated greatly from the original trajectory.By comparing the performance of the two,it can be seen that the capture probability and stability of the composite scanning after the introduction of vibration are significantly higher than that of the spiral scanning.The helic-sinusoidal composite scanning method proposed in this paper can improve the acquisition probability to a certain extent,and has the ability to deal with the complex space environment,which can provide a certain reference for the selection of satellite optical communication acquisition methods in the future.