北斗/GPS双模接收自适应天线阵抗干扰技术及实现

【作者】 傅东宁；

【导师】 郭书军； 邢志强；

【作者基本信息】 北方工业大学 ， 信号与信息处理， 2009， 硕士

【摘要】 我国第二颗北斗2导航卫星于2009年4月15日的成功发射,标志着我国加速步入导航大国的行列,而本文研究正是基于这个大背景展开的。兼容主流的GPS系统和北斗2系统的导航接收机是军用、民用导航的一个趋势,无论从系统的适应性还是定位精度上,双模兼容接收机都具有优势。但当面临敌方卫星、电子战飞机等强干扰信号的威胁时,还需要采用有效的抗干扰技术来确保系统的可靠性。通过分析针对导航接收机的各种干扰,文本提出了在双模基础上的基于天线阵列的空域滤波技术来实现有效干扰抑制,提高接收机信噪比的思路,从而建立一套联合模式切换与空域滤波的抗干扰策略。为实现上述策略,DOA估计算法是其中的关键。文章针对非相干干扰源信号的DOA估计算法进行了理论推导和Matlab仿真,得出了求根MUSIC算法适合于工程实现的结论。而面对干扰源信号在空间传输的多径现象,文章研究了采用四阶累计、前后向空间平滑及MUSIC算法的联合DOA估计算法,有效解决了单纯使用MUSIC针对多径信号估计能力不足的缺陷,在给出详绌理论推导的同时也给出了大量直观仿真。在DOA估计算法的工程实现上,比较成熟的应用均是在DSP中实现,但受DSP体系的限制,运算效率低、速度慢,其瓶颈主要集中在针对复数奇异值分解的运算上。本文提出了求根MUSIC算法中复数奇异值分解(CSVD)在FPGA上实现的算法并在通过从算法模型直接到硬件实现的自上而下的思想在半实物仿真平台上进行了联合仿真实现,得到了算法的验证结果。更多还原

【Abstract】 On April 15,2009,the second BD-2 navigation satellite had been launched successfully.It indicates that China is accelerating into the ranks of great powers in satellite navigation filed.This paper’s study is carried out based on the background of that.Tne dual-mode navigation receiver compatible with GPS and Beidou 2 is a trend in the military and civilian navigation filed.In terms of reliability of the system or positioning accuracy,the dual-mode navigation receiver has advantages. But in the face of the threat of interference signal that comes from the enemy’s satellites or electronic warfare aircraft,the navigation receiver needs to adopt effective anti-interference technology to ensure system reliability.Through the analysis of the various kinds of interference for the navigation receiver,this paper proposed the ideas to achieve interference suppression, improve SNR of the navigation receiver by the use of airspace filter technology based on array antenna,and established a set of anti-jamming strategies by jointing mode switching with airspace filter based on the dual-mode- navigation receiver.In these anti-jamming strategies,DOA estimation algorithm is one of the key. This paper finished the theoretical derivation and simulation by using Matlab for non-coherent interference source signal DOA estimation algorithm,and come to the conclusion that Root MUSIC algorithm is suitable for the realization of the project. In the face of multi-path transmission phenomena of interference signal,this paper presents the joint DOA estimation algorithm by using of fourth-order cumulant algorithm + before-after spatial smoothing algorithm + MUSIC algorithm.The joint DOA estimation algorithm effectively solutes the problem that the MUSIC algorithm failures to work for multi-path signal.In this paper,a detailed theoretical analysis is given,at the same time is also given a great deal of visual simulation.In the realization of the project of the DOA estimation algorithm,as a result of it was hard to direct large-scale complex matrix operation in the FPGA.Therefore the application of maturity is achieved in the DSP,which is inefficient and slow because of the frame of DSP IC.The Bottlenecks mainly concentrated in computation of the complex singular value decomposition(CSVD).This paper presents an algorithm to achieve CSVD in the FPGA,finished a joint simulation of hardware and software based on the topdown thinking that is from the algorithm model directly to the hardware implementation by using the in-the-loop simulation platform,and verified the results of the algorithm.更多还原