Design And Implementation Of Land Mobile Satellite Communication Earth Station Based On The Composite Control Technology

The thesis is aiming at the designing of strap-down mobile satellite communication earth station with two axes, it can sustain signal strength and transmit data, image and voice in mobile carrier. This station is consisted of two axis without rolling axis, so it needs to project the carrier’s angle change in horizontal direction to azimuth and pitching direction of the earth station to offset the error, this condition will be clarified in Chapter section1.There are unavoidable disturbances due to mobile carrier in real functioning, software in servo-control system is needed to isolate these interferences to sustain signal strength and transmit data. Servo-control system acquire motion posture and moving tendency of the carrier through exterior sensors including gyroscope, coded disc, beacon receiver, attitude heading reference system, then obtain the change of antenna direction in geological coordinate system by mutual transformation between carrier’s coordinate system and geological coordinate system, at last output the control variable after the process of PID function, so that driver circuit can drive the motor to rotate the antenna to change its direction and reduce the fluctuation of signal.Software of this system is split into initialization module, searching module, tracking module, interrupt module and serial communication module and so on. Every module is developed and tested separately, the whole system will be tested when all the module are integrated together.