车载卫星天线的自动跟踪算法研究

发布时间：2018-03-10 02:02

本文选题：车载卫星天线　切入点：自动跟踪　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着卫星通信的快速发展以及人们对移动通信需求的不断提高,以传输多媒体宽带数据为主的车载卫星通信得到了人们的普遍关注。在车载卫星通信系统中,天线的自动跟踪技术是保证通信质量的关键。本文针对天线自动跟踪的速度与精度问题展开了深入研究,提出了相应的改进算法。步进跟踪由于设备简单,性能稳定,被广泛应用于车载卫星天线中。但是,由于步长大小所引起的跟踪速度和精度之间存在的矛盾,本文提出使用可变步长的改进算法：在远离目标指向时步长较大,跟踪较快；在接近目标指向时步长较小,跟踪较慢,但跟踪精度较高。同时,对于基本步进跟踪方法在车体运动过程中容易引起方向误判等问题,本文提出使用双向搜索的工作方式基本能够避免方向误判的出现。此外,在一维步进跟踪算法改进的基础上,本文提出在二维步进跟踪过程中驱动天线沿梯度方向调整方位角和俯仰角的工作方式,实现了三维立体空间内天线指向对目标卫星方向的快速逼近。相控阵天线的快速波束扫描能力是实现卫星天线精确对准目标卫星的核心。针对如何改善波束扫描的有效性和可靠性等问题,本文提出一种基于扰动随机逼近(SPSA)的改进算法。该算法利用均匀分布天线相邻单元阵内相位差相等的约束条件,有效估算了接收信号强度关于相位差变化的梯度,调整移相器使相邻单元相位差沿梯度方向变化,从而实现快速波束扫描与跟踪。与多数一维俯仰面相位扫描不同,本文将改进算法成功推广应用至方位面、俯仰面二维波束扫描,进一步提高了天线的跟踪效率。对改进的步进跟踪与波束扫描算法,本文分别进行了相关仿真实验。通过实验结果分析可知,改进算法成功提高了车载卫星天线的自动跟踪能力,实现了载体快速移动中天线与目标卫星的正常通信。此外,关于步进跟踪与波束扫描的联合跟踪算法,本文亦进行了相关原理与实验仿真分析,成功实现了二者的有效结合,完成了车载卫星天线的自动跟踪过程。
[Abstract]:With the rapid development of satellite communication and the increasing demand for mobile communication, the on-board satellite communication, which mainly transmits multimedia broadband data, has been paid more and more attention. The automatic tracking technology of antenna is the key to ensure the communication quality. In this paper, the speed and precision of antenna automatic tracking are studied in depth, and the corresponding improved algorithm is proposed. It is widely used in vehicle satellite antenna. However, due to the contradiction between tracking speed and precision caused by step size, an improved algorithm with variable step size is proposed in this paper: the step size is large and the tracking is faster when the target is far away from the target; When approaching the target, the step is smaller, the tracking is slower, but the tracking accuracy is higher. At the same time, the basic step tracking method is easy to cause the direction misjudgment in the course of the motion of the car body. In this paper, it is proposed that bidirectional search can basically avoid misjudgment of direction. In addition, based on the improvement of one-dimensional step tracking algorithm, In this paper, the working mode of adjusting the azimuth and pitch angle of the driving antenna along the gradient direction in the process of two dimensional step tracking is proposed. The fast approaching of antenna pointing to the target satellite direction in three-dimensional space is realized. The fast beam scanning ability of phased array antenna is the core of realizing the satellite antenna accurately pointing at the target satellite. In view of how to improve beam scanning, this paper discusses how to improve the beam scanning. On issues such as effectiveness and reliability, In this paper, an improved algorithm based on perturbation random approximation (SPSA) is proposed. By using the constraint condition of equal phase difference in the adjacent cell array of uniformly distributed antenna, the gradient of the received signal intensity with respect to the variation of phase difference is estimated effectively. The phase shifter is adjusted to change the phase difference of adjacent elements along the gradient direction, so that the fast beam scanning and tracking can be realized. Different from the phase scanning of most one-dimensional pitch planes, the improved algorithm is successfully extended to the azimuth plane. The tracking efficiency of the antenna is further improved by two dimensional beam scanning of pitch plane. The improved stepwise tracking and beam scanning algorithms are simulated separately in this paper. The improved algorithm successfully improves the automatic tracking ability of the satellite antenna, and realizes the normal communication between the antenna and the target satellite during the rapid moving of the carrier. In addition, the joint tracking algorithm for step tracking and beam scanning is proposed. This paper also carries on the correlation principle and the experiment simulation analysis, has realized the effective combination of the two successfully, has completed the vehicle satellite antenna automatic tracking process.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN828.5

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