Stabilization of Beams of a Satellite Multibeam Hybrid Reflector Antenna Based on Antenna Array Signals in the Presence of Noise
Authors: Романов П.В. 
Published: February 2025

В работе рассматривается эвристический алгоритм стабилизации лучей спутниковой многолучевой гибридной зеркальной антенны, основанный на обработке сигналов антенной решётки, принимаемых от наземного маяка с известными угловыми координатами. Суть обработки сигналов заключается в расчёте и сравнении вблизи номинальной поверхности рефлектора двух полей: поля антенной решётки, возбуждённой сопряжёнными к принятым комплексными амплитудами, и поля распространяющейся в направлении маяка плоской волны, при этом профиль рефлектора, под который пересчитываются лучи, реконструируется как проходящая через центр номинального рефлектора поверхность, на которой разность фаз между фазовыми распределениями сравниваемых полей остаётся постоянной. Приводится анализ влияния шумов как на точность реконструкции профиля рефлектора, так и на эффективность стабилизации лучей. Демонстрируется неожиданное свойство алгоритма реконструкции профиля рефлектора фильтровать принимаемые сигналы.

Introduction. Maintaining the orientation of the beams of a multibeam hybrid reflector antenna (MHRA) of a geostationary satellite with deformations of the reflector profile caused by the variability of the thermal load is a challenging technical problem, that need to be solved to provide the required energy characteristics of satellite communication systems. Along with mechanical systems for compensating reflector profile distortions, operating in tandem with optical devices for profile monitoring, there is currently an increasing interest in electronic beam stabilization. In particular, there has been proposed an effective stabilization method by focusing beams on ground beacons located in the centers of service areas. This method is simple and reliable, but unattractive due to the need to place a large number of ground beacons located strictly near the centers of service areas. The aim of the research is to perform an analysis of the effect of noise on the accuracy of the reconstruction of the MHRA reflector profile, as well as on the algorithm for stabilizing the MHRA beams according to the noise-contaminated signal of the ground beacon. Research algorithm. There is studied an algorithm for stabilizing MHRA beams based on the signals of a single beacon. This algorithm includes an algorithm for reconstructing the reflector profile from beacon signals, which reconstructs the reflector profile as a surface that passes through the center of the nominal reflector and has the constant phase difference between the field of the antenna array (AA), excited proportionally to the complex conjugate of the received amplitudes and the field of the plane wave propagating in the direction of the beacon. Findings. There is shown that proposed technique allows to reconstruct the reflector profile with an accuracy of hundredths of a wavelength, provided that the AA size is sufficient to intercept 90-95% of the reflected beacon signal power, and the distance between the AA elements is less than a certain critical value. The influence of additive white Gaussian noise on both the accuracy of reflector profile reconstruction and the energy efficiency of beam stabilization algorithms is analyzed. The filtering properties of the reflector profile reconstruction algorithm are presented. There is considered an effective method for calculating MHRA in the acoustic approximation, which serves as the base for the beam stabilization algorithm. Besides, mathematical models of typical MHRA deformations are presented.