| Due to various restrictive factors such as geographical environment,construction difficulties,and high construction costs,a considerable number of sparsely populated land areas are unable to receive mobile network signals.Therefore,satellite communications have become a crucial area of research.This paper focuses on the development of a small,low-cost "0.45 m flat panel portable station" and proposes a portable antenna control system based on a flat panel array antenna.The system ensures accurate satellite tracking and fast data interaction with the outside world,making it a significant asset in national defense and security,emergency communication command,public security,border defense,scientific research,and exploration.Firstly,the algorithm for the initial alignment of the antenna is introduced,and the pointing angle necessary to align the antenna with the satellite is calculated via two coordinate transformations.A variety of star-seeking scanning and tracking algorithms are outlined and a new scanning algorithm combining spiral scanning and stepper tracking is proposed based on the traditional star-seeking scanning algorithm.To validate the algorithm’s feasibility,a simulation environment is established using MATLAB and compared against the conventional algorithm.Through simulation experiments,it can be inferred that the novel scanning algorithm that integrates spiral scanning and stepper tracking enhances the system’s velocity and reduces the satellite’s alignment time.Secondly,to address the problem that the stepper motor in the antenna motion control system suffers from out-of-step blocking and slow response time,resulting in the antenna pointing during star finding cannot meet the requirements of fast alignment and high precision control,this article posits a fractional-order PID algorithm for antenna stability control that builds on the traditional PID control algorithm.An improved Oustaloup filter approximation algorithm is used and combined with the parameters of the system to achieve an approximation of the fractional order calculus to obtain the position output of the antenna control system in order to improve the control accuracy and speed of the system.Simulation experiments show that compared to conventional PID control,fractional-order PID control reduces regulation time and optimizes error convergence.Finally,the hardware module selection and circuit design were completed based on the performance indicators and design requirements of the antenna system,with the relevant operational principles explained in detail.Additionally,the software part of the ARM controller was designed and the upper computer monitoring software was written using Lab VIEW.By building the experimental hardware platform,testing each module of the system and completing the joint debugging of the whole system,the final experimental results show that the system can accurately align the stars and shorten the alignment time,basically meeting the design requirements. |
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