Research On Robust Tracking Control Technology For Low Cost Ku Band Vehicle-borne Panel SATCOM On-the-Move

This thesis proposes navigation control method based on low cost MEMS's INS,for the sake of ensuring the carrier to isolate the change of the carrier attitude during the movement,controlling the SATCOM on-the-move antenna always aligns the satellite with high precision for robust tracking control.It includes the method of occlusion detection and pointing adaptive recovery for satellite signals,the calibration of antenna direction and navigation direction drift by sinusoidal scan and AGC signal negative feedback,the design of three axes stabilized platform speed loop coupling compensation PID-type sliding mode controller.A method of satellite signal occlusion detection and pointing adaptive recovery for low cost Ku band SATCOM on-the-move antenna is proposed,based on the law of drift of inertial navigation system and the sine sweep control algorithm of servo motor.The problem of part or all the signals are lost when the satellite signals are blocked by the obstacles causing the antenna pointing shifted is solved,when the vehicle is moving.The method can be divided into four stages,stage one and stage two can correct the antenna pointing immediately,stage three can quickly correct the antenna pointing,stage four is the initial capture of the signal.In this paper,a complete implementation method and a derivation process are given while the method can be used to cope with any occlusion condition.The stable tracking has been realized.Because of the low accuracy of MEMS inertial navigation,the navigation angle of inertial navigation is not affected by gravity,which does not meet the Schuler principle.During the operation of SATCOM on-the-move,the accumulation of errors will lead to the accumulation of the INS,which will further affect the antenna pointing.In order to solve the problem,a method of correcting heading angle drift by using signal difference negative feedback is put forward.It found the linear relationship between the signal difference and the antenna pointing error,using the AGC signal difference to compensate for the difference of antenna azimuth deviation by PID of proportional control method,formatting the closed loop negative feedback by signal intensity.It proves the process is effectively compensated for the drift of the inertial low cost MEMS's INS.For the three axes stabilized platform of SATCOM on-the-move system,thecoupling of angular velocity and shaft,the nonlinear disturbance and the coupling of motor torque and moment of inertia affect the accuracy of control.In this paper,a three axis PID-type sliding mode stability controller is proposed on the basis of the coupling compensation of the axial angular velocity.The coupling compensation formula for angular velocity is given.This speed is used to model the voltage circuit of the SATCOM on-the-move motor.In this model,the three axis sliding mode attitude controller of the antenna is designed through the PID sliding surface,the PID method is introduced to improve the dynamic response speed of the system,at the same time,the adaptive estimation method is used to replace the sliding mode switching law,the smooth sliding mode control input is obtained in the case of unknown disturbance upper bound.It proves the method has good response speed and control precision.