| Mobile satellite communication is a kind of communication service technology, which has a huge space for development. The emphasis of realizing mobile satellite communication lies in ensuring the communication system work normally under the circumstance of moving vehicles. This paper is about the research of stabilizing servo system aiming at the satellite communication of small-bore parabolic dish. The purpose is to isolate the disturbance from moving vehicles, which will affect the antenna pointing, and keep the antenna in alignment with the satellite to ensure communicating fluently.Firstly, the structure of control system has been discussed, and three-axis stabilized control is adopted which is based on sensors at lower cost, stepping motors, and controller. Also effectiveness indicator faced to satellite communication has been given. Calculation formula and aiming satellite measures in the process of antenna initialization has been presented in accordance with the two assignments of antenna's initial pointing and disturbance isolating. Several familiar tracking methods has been introduced and compared, and finally program tracking method has been adopted to realize the adjustment of initial antenna pointing.Secondly, this paper introduces the modular design used to the system's software. Also, three-axis control strategy has been applied to the antenna tracking system, and feed forward control based on the interrupt which can be measured is used to elevation and cross-level control, while the integration of outputs of gyroscopes are used to realize the position feedback in azimuth control. Particularly the Expert PID algorithm has been applied to the azimuth stabilized control which is proved feasible through the simulation. Kalman filtering has been applied to deal with the gyroscopes' zero drift, and dynamically adjust their zero values.Lastly, the result of system commissioning and error analysis has been given, as well the improvement direction of the system. |
PDF Full Text Request