Design Of Tracking Antenna Control System For Low Orbit Satellite

With the rapid development of the Internet of Things,there is a growing demand for satellite communications.Compared with synchronous satellite communication,low-orbit satellite communication has gradually become a powerful supplement to terrestrial cellular network communication with its unique advantages of wide coverage,fast transmission speed and low delay,and is widely used in rescue and disaster relief,remote mountain areas,military communications,and other occasions.However,the low orbit satellite communication project is complicated,and one of its technical difficulties lies in the design of the tracking and control system.Therefore,the study of the tracking antenna control system for LEO satellites can effectively solve the above-mentioned engineering difficulties.The main contents of the study are as follows:Firstly,to address the problem of difficult accurate tracking,the predictive control strategy in advanced control theory is used to solve the problem,which is to predict the trajectory of the target satellite in advance to achieve better control.A geometric model of the inter-satellite geometry is established,and the satellite prediction algorithm is simulated with the help of MATLAB tools;using STK satellite analysis tools,a simulated orbit is built for simulation,and the visibility of the satellite and the accuracy of the SGP4 algorithm prediction are analysed.Based on this,the SGP4 prediction algorithm is improved and compared with the conventional prediction algorithm by simulation.The results show that the prediction accuracy of the improved prediction algorithm is substantially improved.Secondly,in the process of search and tracking,it is easy to increase the overshoot of the system due to the high inertia of the antenna rotation.In this way,the system reduces the overshoot by introducing a feed-forward controller based on the designed position loop.At the same time,a Kalman filter is added to the feedforward control strategy to prevent the tracking accuracy from being reduced due to the interference of noise signals.The model is also built and simulated with the help of Simulink.The results show that the feedforward composite control based on Kalman filter can effectively reduce the overshoot of the system and improve the steadystate accuracy of the system.Then,based on the overall architecture design of the system,the software and hardware design of the LEO satellite tracking antenna control system was completed.The hardware mainly includes the design and implementation of the circuit,and the software includes the development of the upper and lower computers.The upper computer antenna monitoring software is implemented in Qt development environment,using C++ language,for automatic tracking,manual tracking and algorithm analysis of the monitoring software.The lower computer software was developed in the Keil μVision5 development environment using the C language,and its functions such as processing of upper computer commands,acquisition of sensor data,antenna correction and star change were implemented.Finally,modular and systematic testing is carried out by building an experimental platform.The results show that after improving the conventional algorithm and optimising the control strategy,the system can complete the capture of the target satellite within a predetermined time and enter into a stable tracking state,and the tracking performance is excellent,achieving the effect of high-quality communication and meeting the requirements of the indicators at the time of design.