Research And Implementation Of Antenna Tracking Technology In Full Mobile Satellite Communication System

With the progress of science and technology, mobile satellite communications have been developed rapidly. Mobile satellite communication,that is, between mobile users or between mobile users and fixed users, the use of communication satellites as a relay station for communication. The technology is now widely used in a variety of mobile carriers, including cars, trains, aircraft and ships. In the future there is a more extensive application prospects. The key technology in the mobile satellite communication system is to keep the stability of the system and to track the target satellite when the carrier is moving. This technique can be referred to as mobile satellite communication system (MSCS).The key of MSCS is to establish sufficient contact between the satellite and its corresponding ground station, to realize the automatic tracking of the satellite at the ground station, and to keep the antenna wave velocity between the outer space and the ground stable. This system is called the antenna stability tracking system, is also the focus of this article to explore and study the content.In the antenna tracking system, there are many aspects worthy of study, this thesis mainly for the antenna tracking mode and the stability of the way to discuss the platform. Firstly, the basic principle of the technology is briefly described, and the overall frame structure of the technology is described. It includes the composition of the antenna stability tracking system, the basic principle of the antenna stabilization and the basic principle of the antenna tracking. Then, the algorithm of the whole antenna system stability is analyzed and studied in detail. Including the analysis of the "three-axis stability" control strategy, A PID - based system control method is selected, and a data fusion algorithm based on Kalman filter is used to measure the attitude angle and simulated. Then the antenna tracking technology is discussed. Starting from the coordinate system, introduced the commonly used initial alignment technology and tracking technology, and summed up their advantages and disadvantages;The SDP4 / SGP4 model is introduced and the possibility of using it in the system is analyzed; A tracking method based on gradient is put forward and the simulation experiment is carried out according to the common tracking method.Finally, based on the above theoretical research, a satellite antenna tracking system is built on the embedded platform with ARM9 as the core board.The gradient tracking algorithm simplifies the complexity of the receiver,and has a faster speed and higher precision compared with the step tracking.Using the SDP4 / SGP4 model, the speed and accuracy of the antenna are greatly improved in alignment. In the design of the hardware also joined the special control of the motor under the machine, the lowest price of the motor speed changes in the noise, the performance was optimized.