Research And Implementation Of Ship Borne Earth Station Tracking System Based On FPGA

With the continuous application of new technology in satellite communication,A variety of light,small volume,mobile,powerful " mobile communication " earth stations have appeared,and higher requirements for tracking performance have been put forward.The traditional tracking system basically uses single-chip computer to implement tracking algorithm.Its slow operation results in slow response of the tracking system and more complex calculation cannot be achieved.In order to solve this problem,this dissertation studies and designs a ship-borne earth station tracking system based on FPGA,and puts forward an improved performance attitude fusion algorithm and a motor control strategy.Firstly,this dissertation studies and compares the principles,advantages and disadvantages of three automatic tracking algorithms,and determines the selection of key parameters of the cone scan used in the tracking system.Then,the basic composition of the ship-borne earth station and the workflow of the tracking system are introduced.From this,the overall scheme structure of the whole tracking system is determined,and then the mathematical model of the star process and the transformation process of the coordinate system are analyzed and deduced.In the next part,this dissertation focuses on the hardware circuit and embedded software designed in this subject.The hardware circuit is designed and implemented based on FPGA,and the calculation complexity of cone scanning principle needs to be considered in the design,while the Verilog language design in software design needs to consider the cooperation and concurrent work between various modules.Aiming at the improvement of the performance of the tracking system,this dissertation proposes an attitude fusion algorithm to optimize the inertial measurement unit and an improved motor control strategy.Experiments show that,compared with the traditional Kalman filter,the attitude fusion algorithm reduces the angle offset caused by the gyro zero drift and smoothes the stepped curve when the three-axis angle changes.The improved motor control strategy includes stepping motor control strategy and cone scanning DC motor control strategy.The former improves the shortcomings of traditional PID control of stepper motor,and adopts adaptive incremental PID control.It first makes rapid adjustment,and then controls the overshoot to eliminate the static error,so as to achieve faster and more accurate adjustment.The latter proposes an adaptive speed regulation strategy based on the initial phase estimation,which reduces the influence of the sub reflector vibration caused by the conical scanning algorithm of the earth station.The experimental results show that the attitude fusion algorithm and motor control strategy are used in the tracking system of the earth station,which can better complete the task of tracking the target satellite and achieve reliable satellite communication.