【作者】 刘思沉；

【导师】 刘峥；

【作者基本信息】 西安电子科技大学 ， 信号与信息处理， 2010， 硕士

【摘要】 随着短波通信技术的发展,扩频信号、跳频信号、线性调频信号等宽带信号在短波通信系统中的应用越来越多,因此对突发、短时信号测向的要求越来越迫切,短波宽带接收测向技术就成为短波测向技术研究的重点和难点。由于相对带宽较宽,传统的窄带测向技术已经不能满足宽带测向系统的要求。如何快速准确的估计出宽带内众多信号的波达方向及其空间分布,如何解决宽带测向系统带来的海量数据处理,这些就是本文需要探讨解决的问题。目前,国内外通常采用的宽带测向技术有两种：一种是标准干涉仪测向算法,这种算法具有运算量较小、测向较为准确的优点,但在实际应用中由于系统误差的存在使得频率高端常发生解模糊错误导致测向的失效,影响整个系统的测向效果。另一种是相关干涉仪测向算法,这种算法利用阵列实际响应信号与阵列理论响应模版的相关性解决模糊问题,测向准确度也大大提高。在短波测向中,传统的相关干涉仪需要生成全空域的相关结果,通过搜索相关峰的方式来确定信号的仰角和方位角。对于宽带测向而言,相关处理需要与大量的原始样本做相关运算,其运算量非常大,通常采用高性能服务器或嵌入式处理器构成分布式处理平台进行处理计算,使得系统架构复杂、成本高昂,还很难满足宽带测向系统的时效性要求。本文基于相关干涉仪测向体制提出了一种改进型相关干涉仪测向算法。算法通过引入空间夹角的概念,使得原始样本数据大大减小,从而使得在保证测向精度的前提下,算法的运算量大大降低。改进后的算法适用于常用的圆阵和L型天线阵,由于运算量比相关干涉仪大大降低,在工程实践中也得到了很好地应用,不失为标准干涉仪解模糊的一种较好的方法。针对宽带测向应用,本文研制完成了一款高性能信号处理模块,该模块由多通道AD和多片大规模的FPGA组成。本文采用FPGA完成测向阵列信号预处理运算、和所有子信道的相关运算,使得整个宽带测向系统的构架简单可靠,体积、成本也大大降低。更多还原

【Abstract】 With the development of shortwave communications, wideband signals including spread spectrum signal, frequency hopping signal and linear FM signal have been widely used in modern shortwave communication systems, which makes great demands on direction finding against burst and short-time signals. The shortwave wideband receiving DF technique has become the key point in the research area of shortwave DF. The traditional narrow band DF technique can’t meet the requirements of wideband DF systems. This paper discusses how to estimate both DOA and spatial distribution of various signals in the wideband domain quickly and accurately and how to process mass data caused by wideband DF systems.At present, the widely used wideband DF technique at home and abroad includes the standard interferometer DF algorithm and the correlative interferometer DF one. The former has the merits of small calculating amount precise DF and the demerit of interferometer ambiguity-resolving errors to result in DF failure. The latter uses the correlation of raw sample data to avoid phase ambiguity and improve DF precision. In shortwave DF, the traditional correlative interferometer determines the azimuth and elevation angles of signals by searching the coherence crest value in all-aerospace and round-the-clock data. As to wideband DF, the correlative processing is computationally expensive on the basis of a mass of original data and usually uses the high-performance server or the embedded processor to form a platform for distribute processing, which is complicated, expensive and unable to meet the timeliness.This paper presents an improved correlative interferometer DF algorithm which introduces the concept of space angle to reduce raw sample data and lower computational complexity under the precondition of high accuracy of DF. Suitable for circular array and L-shape array, this algorithm is good for practical application in engineering for small computation, which shows it is a good method for implementation of phase ambiguity resolution of standard interferometers.Aimed at the application of wideband DF, the paper proposes a high-performance signal processing modular consisting of a multichannel AD and large-scale FPGAs. The paper uses FPGA for preprocessing of DF array signals and for correlative computation of all sub-channel, which makes the configuration of the wideband DF system simple, light, economic and reliable.更多还原