| The Variable Inclination Continuous Transverse Stub(VICTS)antenna,as a novel ultra-thin SOTM,has the advantages of low profile,easy conformal installation,and low cross-beam interference.To make full use of the beam scanning performance of this antenna,a reliable,stable and real-time servo control system is needed.In this paper,based on the study of the operating principle of the novel ultra-thin SOTM,the performance indicators of the servo control subsystem are analyzed.In order to achieve high-precision control and low-profile design of the antenna system,the hardware and tracking of the servo control system,tracking algorithm and low-profile rotary joint are analyzed and designed.The main research results and innovations achieved are as follows:(1)According to the working principle and unique structure of the novel ultra-thin SOTM,a servo control system based on the ARM + FPGA hardware architecture is designed.The servo control system can realize fast and precise control of the novel ultra-thin SOTM beam.According to the system's joint adjustment and performance measurement,the servo control system based on the novel ultra-thin SOTM meets the designed performance indicators and can realize the reception and demodulation of satellite signals.(2)Aiming at solving the problem of low efficiency of the step tracking of the novel ultra-thin SOTM,a variable step size tracking algorithm is proposed based on the hardware architecture of the servo control system and the mapping relationship between the rotation angle of two-dimensional plane and the spatial stereo beam.According to the beam scanning result of the new ultra-thin moving antenna and the approximate half-power lobe width calculation formula,the search step size under different beam directions is obtained,and then the tracking direction and tracking step size are determined by the search result.Simultaneously,the research and test of the beacon machine,and the method of averaging the data of multiple beacon machines to improve the reliability of the beacon machine data.It has been verified by actual measurement that compared with the traditional step tracking algorithm,the variable step size step tracking algorithm improves the tracking speed on the basis of ensuring the tracking accuracy.(3)In order to reduce the overall profile height of the novel ultra-thin SOTM,a Ku-band rotary joint based on a flat waveguide was designed.The multi-stage Chebyshev transform step was used to realize the impedance conversion of the standard waveguide-flat waveguide in a limited size;The design idea of using the coaxial structure as the transition structure solves the impedance matching problem of the coaxial-waveguide.The standing wave characteristics of the rotating joint under different rotation angles are simulated.The results show that the return loss and insertion loss performance of the rotating joints under different rotation angles are good. |
