海面动目标的检测及其FPGA实现技术研究

发布时间：2018-03-25 11:35

本文选题：K分布海杂波　切入点：最优检测　出处：《电子科技大学》2014年硕士论文

【摘要】：海面动目标的检测是雷达信号处理领域中的一个研究热点,在民用和军用方面都占有十分重要的地位。随着作用距离、多普勒分辨率、距离分辨率、实时性、可靠性等要求的提高,如何改善雷达回波的信杂比,并在强海杂波背景中更有效地检测出运动目标,成为了急待解决的研究问题。本文针对海杂波严重干扰雷达对低速和高速动目标检测的问题,在研究动目标特性的基础上,开展了海杂波背景下动目标检测及其FPGA实现技术的研究。第一,研究和讨论了不同海杂波模型的统计分布特性,分别对舰船等海面低速动目标以及导弹、飞机等高速动目标的回波特性进行研究,建立回波模型,并对动目标的时域和频域特性进行仿真。第二,针对低速动目标的多普勒频移接近海杂波中心频率的问题,研究了K分布海杂波背景下低速动目标的最优检测(OD)和广义似然比检测(GLRT),深入分析了K分布海杂波形状参数、尺度参数以及相干积累脉冲数对OD和GLRT算法的影响,利用辅助杂波距离单元估计海杂波的归一化协方差矩阵。在此基础上,采用特征值分解和多普勒相位空间搜索两种方法估计目标的多普勒频移,并对相位搜索GLRT的运算量进行了改进。最后,通过蒙特卡洛仿真试验比较和分析了K分布海杂波背景下OD和GLRT的检测性能,以及GLRT在方向矢量未知条件下的检测性能,并采用IPIX海杂波数据进行处理验证。第三,针对高速动目标在长时间相干积累中存在距离走动和多普勒模糊现象的问题,深入研究了基于Keystone变换(KT)和Radon-Fourier变换(RFT)的高速动目标检测方法。首先,分析和比较了三种不同KT实现方法对运动目标距离走动的补偿。其次,基于运动目标的径向速度、距离走动和多普勒频移之间的耦合关系,研究了速度和距离联合搜索的RFT算法,并对多普勒补偿函数进行互补加权,抑制RFT的盲速旁瓣现象。最后,通过大量的蒙特卡洛仿真试验比较和分析Keystone变换和RFT在海杂波背景下海面高速动目标的检测性能。第四,在ISE开发环境中,对海面低速动目标的GLRT算法进行FPGA仿真,并与MATLAB的仿真结果相比较。本文研究的方法在低SCR下分别可以有效地检测出海面低速和高速动目标。
[Abstract]:The detection of moving targets on the sea surface is a hot topic in radar signal processing, which plays an important role in both civil and military fields. With the improvement of reliability, how to improve the signal-clutter ratio of radar echo and detect moving target more effectively in the background of strong sea clutter, It is an urgent problem to be solved. In this paper, the characteristics of moving targets are studied based on the detection of low speed and high speed moving targets by sea clutter serious jamming radar. The research of moving target detection and its FPGA implementation technology in sea clutter background is carried out. Firstly, the statistical distribution characteristics of different sea clutter models are studied and discussed. The echo characteristics of high-speed moving targets such as aircraft are studied, the echo model is established, and the time-domain and frequency-domain characteristics of moving targets are simulated. Secondly, the Doppler frequency shift of low-speed moving targets is close to the center frequency of sea clutter. The optimal detection of low speed moving targets in the background of K-distributed sea clutter and the generalized likelihood ratio (GML) detection are studied. The effects of shape parameters, scale parameters and the number of coherent integrated pulses on the OD and GLRT algorithms are deeply analyzed. The normalized covariance matrix of sea clutter is estimated by the auxiliary clutter distance unit. On this basis, the Doppler frequency shift of the target is estimated by eigenvalue decomposition and Doppler phase space search. Finally, the detection performance of OD and GLRT under the background of K-distributed sea clutter and the detection performance of GLRT under unknown direction vector are compared and analyzed by Monte Carlo simulation. The IPIX sea clutter data is used to process and verify. Thirdly, aiming at the problems of range walk and Doppler ambiguity in the long time coherent accumulation of high speed moving target, The methods of high speed moving target detection based on Keystone transform (KT) and Radon-Fourier transform (RFT) are studied in depth. Firstly, three different KT realization methods are analyzed and compared to compensate the moving target range walk. Secondly, based on the radial velocity of moving target, The coupling relationship between range walk and Doppler frequency shift is studied. The RFT algorithm of velocity and range joint search is studied, and the complementary weighting of Doppler compensation function is carried out to suppress the blind velocity sidelobe phenomenon of RFT. A lot of Monte Carlo simulation experiments are carried out to compare and analyze the detection performance of Keystone transform and RFT in sea surface high speed moving target under sea clutter background. Fourthly, in the ISE development environment, the GLRT algorithm of low speed moving target is simulated by FPGA. Compared with the simulation results of MATLAB, the method studied in this paper can effectively detect low speed and high speed moving targets at low SCR.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN957.51

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