Development And Application Of Automatic Tracking Control System For Shipborne Satellite Communication

The 21 st century is a highly information-based society.The development of communication has made it more convenient for people to communicate with each other.Therefore,people rely more and more on communication.In all kinds of communication methods,satellite communication has been occupying an important position because of its flexibility,large capacity of communication and not restricted by region.In the field of satellite communications,satellite communications are mostly used in the fixed stations in China and the technology is gradually maturing,but the functions of real-time communication of carriers in motion can't be satisfied.Considering that the earth has more than 70% of the ocean area,microwave forwarding method can not achieve ocean communication,which results in the obstacle between the naval vessels and the fishing vessels,therefore it is quite urgent to develop a stable ship-carrying "mobile communication" system.The main contents and achievements of this thesis are as follows:(1)A ship-carrying "mobile communication" system entity is designed,which includes a control system and an antenna feeder system,so as to align the target satellite faster through the tested data from the simulation platform,ensuring The carrier in motion can communicate with the target satellite in real time.(2)Based on the attitude information provided by the antenna,the star angle in the geo-coordinate system is deduced by the space rotation coordinate system and the plane geometry triangulation method.In order to solve the problem that the antenna has high requirement to the star angle,the original model is improved,and a more accurate calculation model of the pointing angle is given.The method of calculating the angle of the star in the vector coordinate system is proposed due to the external instability,The simulation results show that this model can improve the performance of large-aperture antenna.(3)The cone scan algorithm is used to track the target satellite and to track the target continuously after the initial star action is completed by the ship-carrying "mobile communication".the realization method of the algorithm and AGC control technology in the system are also analyzed.(4)The classical PID controller has the disadvantage of large overshoot and instability,in order to improve the performance of the system,an improved PID-Fuzzy piecewise combined controller is proposed.Through testing,this algorithm can no only exert the characteristics of good dynamicperformance and strong adaptability of fuzzy controller,but also can exert the characteristic of the traditional PID controller without static difference and static performance,which improve the performance of the system.