时空二维侦察处理技术

【作者】 刘华东；

【导师】 陈天麒；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2003， 硕士

【摘要】 宽频段高分辨率时-空二维谱估计是当前阵列信号处理研究的一个重要方向，虽然在众多学者的努力下已取得了丰富的理论成果，但是一直以来宽频段阵列系统的工程实现存在很多困难。近年来随着微电子技术的发展，以及高性能时空二维谱估计算法的出现，使宽频段高分辨率时-空二维谱估计准实时系统的硬件实现成为可能。在本实验系统中，我们设计了一个5阵元的L型非均匀阵列天线，将的频段划分成的子频段，然后将每个子频段混频到的处理基带后再进行的同步欠采样。其中有一个阵元输出有一通道经延时后再采样。对采样数据进行FFT和谱峰搜索，截取谱峰附近数据构造一路信号的四阶累积量矩阵和二路信号的互四阶累积量矩阵，构成了一对ESPRIT算法所需要的旋转不变矩阵束。利用特征值相位和基于整数搜索法来实现信号频率和二维到达角的无模糊估计。本文主要介绍了基于四阶累积量的时-空二维谱估计算法，并以此为基础来实现时频空三维侦察机；宽频段阵列系统各种误差参数的校正算法，实验系统的硬件驱动程序的开发和应用软件的开发。系统采用当前比较先进的DSP技术和PCI局部总线技术，样机由三块FFT卡和一块主处理卡组成，其中FFT卡选用的是TMS320C31 DSP，而主处理卡采用的是TMS320C67 DSP。系统选用工控机为控制平台，Windows为操作系统。为了实现硬件卡之间、应用程序和硬件卡之间的数据传输，需要开发VxD驱动程序，本文详细介绍了驱动程序的开发过程。在阵列信号处理中，阵列系统的各种误差对算法性能的影响是比较大的，所以本文也对阵列的各种误差校正算法进行了研究。该样机系统还属于实验性研制阶段，但通过模拟试验结果表明，该处理机可对时空均欠采样的数字信号进行频率和二维到达角的无模糊估计，并且性能达到预期设计的要求。虽然该处理机是用来处理平稳窄带信号的，但是该实验样机为非平稳信号的参数估计系统的研制提供了许多理论和工程经验，也为高分辨率时-空二维谱估计技术的实际应用打下了坚实的基础。更多还原

【Abstract】 The high-resolution spatio-temporal two-dimensional (2-D) spectra estimation of wide-band signal acts an important role in modern array signal processing. Though abundant results acquired in theory, there are a lot of difficulties in the real time application of wide-band system. The development of micro-electronic and high performance algorithms of spatio-temporal 2-D spectra estimation offered probability for us to apply it on a real time system now. In prototype system, a L-shaped non-uniform linear array with 5 elements is utilized to receive spatial signal with carrier frequency among 2-18GHz. The entire frequency band is decomposed into 1GHz sub-bands and then is mixed to 1GHz base band. The base band output of each antenna is sent through a synchronous 250MHz undersampling channels. One antenna has a delayed 0.5ns relative to the others (prior to sampling). FFT is applied to data and spectra peak search is done, then using the data near the spectra peaks to compute two 4th-order cumulants matrix to form rotational invariance matrix pencil which the ESPRIT algorithm can be applied to. The non-aliasing frequency and non-ambiguous 2-D angles is obtained by the phase characteristic of eignevalue and integral search methodIn this dissertation, an algorithm of spatio-temporal 2-Dspectra estimation based on 4th-order cumulants was introduced and used to realize a prototype scout, a calibration algorithm in the wide-band array system is proposed. It also presents the development of hardware driver and application software for the prototype system. The technique of DSP and PCI local bus were applied in the system. Three FFT boards (TMS320C31 DSP) and one main processing board(TMS320C67 DSP) contributed to the system. We used the special computer as the controlling platform and Windows as the OS. The development of VxD driver software is describe in detail which is used to realize data transferring between hardware and application software, also data transferring among all boards. In array signal processing, various kinds of errors can degrade the performance of signal processing algorithm, errors calibration algorithm is also studied in this dissertation.<WP=5>Now our prototype system is in experiment, but the simulation result show that it can do non-alias frequency and 2D-DOAs of spatio-temporal undersampling digital signal and obtain the aimed performance. Though out system is designed to process stable narrow-band signal, it also provide experience for study of unstable signal parameter estimation system in theory and engineering, and establish a basement for the application of high-resolution spato-temporat 2-D spectra setimation.更多还原