卫星激光通信粗瞄控制子系统优化设计

发布时间：2018-12-15 22:20

【摘要】：随着科技的高速发展,卫星作为空地间通信的重要载体,人们对其通信质量的要求也随之提高。相比于传统的微波通信,卫星激光通信作为新型的通信方式,具有频率高、波长短、方向性佳、波段相对独立和保密性强等优点,故卫星激光通信自从诞生之日起就展现出蓬勃的生命力,成为各国研究热点。在卫星激光通信系统中,为了维持良好的通信链路,我们必须建立起捕获、瞄准和跟踪(Acquisition、Pointing and Tracking,APT)系统,粗瞄控制子系统是APT系统的重要组成部分。本课题以哈尔滨工业大学承担的“中继卫星星间链路技术”课题为背景,对其粗瞄控制子系统各部分进行深入研究和优化,提出假设并进行了相应仿真和实验进行验证。扫描捕获作为APT系统的关键步骤,本文首先对星间光通信的扫描捕获过程进行说明,阐述了目前常用的扫描捕获方式,然后通过模型建立和仿真提出优化方案,其中包括分别应用于单场扫描和多场扫描情形下的优化,结合螺旋和正弦扫描提出新型扫描方案,以及针对粗瞄误差的不对称性较高时的扫描方式选择。其次,针对目前粗瞄反馈环节出现的问题进行分析,对反馈测量器件绝对式光电码盘提出误差补偿的复合算法;并对解码单元板的粗码译码电路进行优化改进,以期其适应如火箭发射引起剧烈振动导致的机械结构变形或外太空高低温等因素造成的各类误差所带来的影响。最后,针对粗瞄控制单元的控制算法进行优化。指出目前课题中使用的增量式PID算法在实际工作中存在的不足,然后介绍了具有快速响应、对参数变化和扰动不敏感、无需系统的在线辨识和建模的滑模变结构控制,并进行了仿真分析。提出滑模变结构控制器作为增量式PID控制器的备份,在太空中待命工作,以期达到最好的粗瞄控制效果,为后续精瞄控制系统达到所维持良好通信链路提供必要的精度。
[Abstract]:With the rapid development of science and technology, satellite as an important carrier of communication between air and air, people's requirements for communication quality are also raised. Compared with traditional microwave communication, satellite laser communication, as a new communication mode, has the advantages of high frequency, short wavelength, good directivity, relatively independent band and strong confidentiality. Therefore, satellite laser communication has shown vigorous vitality since its birth, and has become a research hotspot in various countries. In the satellite laser communication system, in order to maintain a good communication link, we must establish a capture, aiming and tracking (Acquisition,Pointing and Tracking,APT) system. The coarse aiming control subsystem is an important part of the APT system. Based on the "Intersatellite Link Technology of Relay Satellite" subject of Harbin University of Technology, this paper makes a thorough study and optimization of each part of the coarse pointing control subsystem, and puts forward the hypothesis and carries out corresponding simulation and experiment to verify it. Scanning acquisition is the key step of APT system. Firstly, the scanning acquisition process of inter-satellite optical communication is explained, and the commonly used scanning acquisition method is expounded, and then the optimization scheme is proposed through modeling and simulation. It includes the optimization of single-field scanning and multi-field scanning, the combination of spiral and sinusoidal scanning, and the selection of scanning mode when the coarse scan error is high. Secondly, based on the analysis of the problems existing in the feedback link of coarse sight, a compound algorithm of error compensation is proposed for the absolute photoelectric code plate of feedback measurement device. The coarse-code decoding circuit of the decoded unit board is optimized and improved in order to adapt to the influence of various errors caused by the mechanical structure deformation caused by the intense vibration caused by rocket launch or the high and low temperature in outer space. Finally, the control algorithm of coarse aim control unit is optimized. This paper points out the shortcomings of the incremental PID algorithm used in the present project, and then introduces the sliding mode variable structure control with fast response, insensitive to parameter variation and disturbance, and no need for on-line identification and modeling of the system. Simulation analysis is also carried out. A sliding mode variable structure controller is proposed as the backup of incremental PID controller, which can work on standby in space in order to achieve the best coarse aim control effect and provide the necessary precision for the subsequent fine aiming control system to achieve the good communication link maintained.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN929.1
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本文编号：2381376