| The maritime satellite communication is an important part of mobile satellite communication system. Along with the development of information technology, maritime satellite communication system has been able to provide services in different fields, not only distress and safety communication at all. And now, it has been increasingly widely used. The tracking control system could control the maritime satellite antenna to search satellite signals automatically and carry out compensation on the antenna attitude in order that antenna could track the satellites to ensure the normal communication during the movement of carrier. Therefore, the research on the antanna tracking control systerm is of great significance.The antenna controller studied in this thesis uses TI's TMS320F2812 as central processor, with peripheral modules such as sensors, motor driving unit, extended serial interface, GPS and so on. Based on this hardware, the software of the tracking control system is designed to control antenna to rotate, seeking satellite signals all through the sky. According to the signal strength provided by BDU, the maximum point of satellite signals could be determined. Then the antenna tracks satellite in the vicinity of this position. As the antenna carrier is sailing, ACU software should obtain the attitude changes of the carrier through sensors, then in accordance with the compensation algorithm, get the compensation angles for the antenna attitude. Thus the elevation and azimuth angle of the antenna could be ajusted to achieve stable tracking.This thesis is composed on the basis of the ministry of transportation project "Research on Key Technologies of Ship-borne Satellite Terminal Antenna". The main contents include the modular software design of the antenna tracking control system as well as the software synthesization and debugging within CCS intergrated development environment. The communication protocol and process between ACU and PC during system detects is analyzed in detail, under which the communication software between ACU and PC is designed based on the extended serial interface. According to the stabilized platform and the compensation algorithm of antenna controller, data collected by the sensors plays an important role in the antenna stability compensation. Next the software is designed to collect information from sensors. Through the communication software, the data of inclination sensor and the gyro sensors is transported and displayed in the diagnostic software on PC, which shows the achievement of sensor test through diagnostic software. Moreover, the software designs of other modules, such as initialization, auto-searching and tracking, serial communication, motor driving etc, are illustrated in the thesis. The interfaces between modules throughout the whole operation is described too, as well as the allocation of system resources in cmd file. The design has achieved the basic functions of antenna controller. |
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