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本文提出了一种适用于MIMO阵列雷达的简便的CFAR检测器,它利用了MIMO阵列雷达观测空间维数高的特点,通过直接滤除杂波干扰子空间的方式抑制杂波和干扰。该检测器的简便性在于杂波子空间可以离线估计与存储,而干扰子空间的估计也只需在低维空间上进行,而其原因是在估计杂波和干扰子空间时没有利用距离参考单元观测样本,而是利用了已知的系统参数、杂波子空间结构以及干扰协方差矩阵的模块对角性质。仿真结果表明,在杂波的理想模型条件下,选择适当的估计方法可以获得较高的杂波子空间估计精度,由此得到的CFAR检测器的性能也非常接近于已知杂波干扰子空间条件下的检测性能。 相似文献
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Fu-Kun Bi Dong-Yan Zhang Xi-Chang Cai Lin Li Yong-Xu Liu 《International Journal of Electronics》2013,100(8):1382-1393
In the reduced-rank space-time adaptive processing (STAP) methods, especially the principal component (PC) analysis STAP method, a set of dominant eigenvectors must be obtained by singular value decomposition of the space-time covariance matrix. Therefore, it is very difficult to be applied in practical system due to the intense computational complexity. In order to reduce the computational burden, a fast reduced-rank STAP algorithm based on Gram–Schmidt (GS) orthogonalisation is proposed in this article. In the proposed GS-PC STAP method, the clutter subspace is reconstructed by the GS orthogonalisation of training samples. Then, the STAP adaptive weight vector is calculated by orthogonally projecting the quiescent weight vector into clutter subspace, which can hold fast convergence measure of effectiveness (MOE) and require less computational complexity by compared with the conventional PC method. Based on the simulated data and multichannel airborne radar measurements data, the corresponding convergence MOE and the clutter suppression performances are verified in the article. 相似文献
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《Signal Processing, IEEE Transactions on》2008,56(12):5926-5936
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This paper proposes a novel method of unimodular transmitting waveforms design for multiple-input multiple-output (MIMO) radar to strengthen the detection performance in the presence of clutter and white Gaussian noise. An improved iterative algorithm is put forward to maximize the signal-to-clutter-plus-noise ratio (SCNR) under the constant modulus constraint. During iterations, the optimization of unimodular waveforms with filters fixed is a nonconvex fractional quadratically constrained quadratic program problem, which is NP-hard and not able to be solved in polynomial time. An algorithm based on semidefinite programming relaxation combined with bisection and Gaussian randomization is introduced to provide the high-quality suboptimal solutions with a polynomial time computational complexity. The analysis on the approximation bound is given to prove the tightness of the semidefinite programming relaxation and so the correctness of the proposed algorithm. The simulation results show that the improved method is efficient in designing unimodular waveforms for MIMO radar to achieve a better SCNR performance. 相似文献
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A subspace method for space time adaptive processing 总被引:4,自引:0,他引:4
The problem of space-time adaptive processing (STAP) using a nonlinear array is considered. A key part of STAP is the estimation of the space-time covariance matrix of the received data. The conventional method of doing this causes significant performance degradation at short ranges because of the nonstationarity of the data. We present an alternative algorithm which circumvents this problem by projecting the data on the subspace orthogonal to the clutter and jammer subspaces. The clutter subspace is computed from the known array manifold, while the jammer subspace is estimated from clutter-free measurements. Numerical examples illustrate the performance improvement achieved at short ranges. 相似文献
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机载MIMO雷达可联合利用时间自由度、发射和接收空间自由度抑制杂波,但只能利用接收空间自由度抑制有源干扰。基于此特点,该文提出一种机载MIMO雷达的两级空时自适应处理方法抑制杂波和干扰。第1级处理中只利用部分空间接收自由度进行干扰抑制,同时实现降维处理;第2级通过匹配滤波获得发射空间自由度,并联合剩余接收空间自由度和时域自由度,进行空时联合自适应处理抑制杂波。该方法通过分级处理既有效利用了MIMO雷达的发射自由度进行杂波抑制,又同时大大减低了计算量和样本需求。理论分析表明存在强干扰时,两级处理的理论性能可以逼近全维处理的最优性能。仿真实验表明了该算法的有效性。 相似文献
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在机载雷达体制中,空时自适应处理STAP(Space-Time Adaptive Processing)可有效抑制杂波并显著提高雷达对慢动目标的检测性能.但是在非均匀环境中,缺乏独立同分布的训练样本会使STAP性能严重下降.针对这个问题,本文提出一种基于多帧观测联合感知的空时自适应处理方法.该方法交替发射正交信号和普通的相控阵信号.检测前,通过当前及先前的环境回波感知观测场景获取杂波信息;检测时,先利用杂波信息结合平台参数及系统参数估计杂波协方差矩阵,再将估计的协方差矩阵与样本协方差矩阵进行组合以构造空时滤波器,抑制杂波,提高输出信杂比.仿真结果表明,与现有的知识辅助类STAP算法和降维算法相比,该方法在缺乏准确先验知识的情况下,可以有效地抑制非均匀杂波. 相似文献
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有源干扰条件下机载MIMO雷达STAP协方差矩阵秩的分析 总被引:1,自引:0,他引:1
该文分析了正侧阵机载MIMO雷达杂波加有源干扰协方差矩阵的结构,得到杂波加有源干扰协方差矩阵秩的上界为杂波的秩与有源干扰的秩之和减去有源干扰个数。并由此得到MIMO雷达杂波加有源干扰协方差矩阵非满秩而SIMO雷达杂波加有源干扰协方差矩阵满秩时有源干扰个数的范围。当有源干扰的数目在此范围时,SIMO雷达的理论性能严重下降,而MIMO雷达在理论上仍然有足够的自由度来抑制杂波和有源干扰,从而保证有较好的性能。通过仿真实验验证了上述结论。 相似文献
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MIMO Radar Waveform Optimization With Prior Information of the Extended Target and Clutter 总被引:1,自引:0,他引:1
《Signal Processing, IEEE Transactions on》2009,57(9):3533-3544
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Parameter identifiability is one of the most interesting issues in multiple-input multiple-output (MIMO) radar systems. Previous works have presented conditions for parameter identifiability of the systems with uncorrelated waveforms. In this paper, under general waveform assumptions, we investigate conditions for parameter identifiability of MIMO radar systems with more flexible waveform diversity, where the transmitted waveforms are not restricted to be uncorrelated. The conditions specify the maximum number of targets that can be uniquely localized, which are obtained based on the rule of time-bandwidth product. Moreover, it is found that the conditions are in terms of the rank and structure of the waveform covariance matrix (WCM) and the geometry of MIMO radar systems. Numerical examples are provided to verify the effectiveness of the conditions. 相似文献
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Space-time adaptive processing (STAP) techniques provide simultaneous rejection of jamming and clutter in airborne radar. The greatest benefits over conventional MTI (moving target indication) approaches are in terms of a capability to detect slow-moving targets which possess the same Doppler frequency as mainlobe clutter returns. This paper examines the effects of platform manoeuvre on STAP clutter and jamming rejection performance for a forward-facing array (i.e. where the array is orientated transversally to the direction of travel). It is shown that STAP slow-target detection performance is not sensitive to the radar platform orientation. It is also demonstrated that, under conditions of manoeuvre, STAP can provide better jammer rejection performance than architectures which cascade conventional clutter filtering and spatial adaptive beamforming 相似文献
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针对机载MIMO雷达杂波空时耦合的特性,提出了一种应用于机载MIMO雷达的空时杂波块对消器。利用MIMO雷达接收杂波的多普勒相位和空域接收相位之间的关系,设计系数矩阵来对消杂波,后续级联空时自适应处理方法能进一步抑制杂波和提高动目标检测性能。仿真实验表明,该杂波块对消器能对正侧视和非正侧视机载MIMO雷达均有较好的杂波抑制能力,从而进一步提高了后续空时自适应处理算法的动目标检测性能。 相似文献
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非均匀环境下,机载MIMO雷达杂波不再满足独立同分布(independent identically distributed, IID)条件,由于没有足够多的IID样本来估计杂波协方差矩阵,从而导致传统的STAP方法性能急剧下降。本文研究了非均匀环境下机载MIMO雷达的杂波抑制问题,将空时自回归算法(Space time autoaggressive , STAR)引入机载MIMO雷达,降低训练样本数目,减小运算量。针对STAR算法中参数确定复杂、易受训练样本数目不足影响的缺点,提出了一种基于杂波特征结构的模型参数确定方法,仿真结果表明,该方法能在极小训练样本条件下,有效确定模型参数,实现杂波抑制,适用于非均匀杂波环境。 相似文献
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Guolong Cui Lingjiang Kong Xiaobo Yang Jianyu Yang 《Circuits, Systems, and Signal Processing》2012,31(1):237-254
In high resolution radars, the distributed target is usually modeled as a few isolated points referred to multiple dominant
scattering centers, while the clutter is a compound-Gaussian model. Additionally, the polarimetric diversity can be exploited
to enhance detection performance. Motivated by extending the detection problem of multiple-input multiple-output (MIMO) radar
to such cases, this paper mainly addresses distributed targets detection problem with polarization MIMO radar against a compound-Gaussian
clutter dominated scenario with unknown covariance matrix. The adaptive detectors based on Rao and Wald criteria are studied,
and a two-step design procedure is adopted. Specifically, the Rao and Wald tests are derived by assuming a known covariance
matrix, and then a suitable estimation of the covariance matrix based on the secondary data is inserted into the derived detectors
to make them fully adaptive. Some numerical results are presented together with a polarization generalized likelihood ratio
test (GLRT), showing that the derived detectors provide excellent detection performance in spiky clutter for distributed targets,
and that the polarimetric diversity can be exploited to improve detection performance. Overall, the Wald test performs the
best. 相似文献
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Iterative Adaptive Approaches to MIMO Radar Imaging 总被引:1,自引:0,他引:1
Roberts W. Stoica P. Li J. Yardibi T. Sadjadi F. A. 《Selected Topics in Signal Processing, IEEE Journal of》2010,4(1):5-20
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高重复频率前视阵机载雷达地杂波不仅存在严重的距离依赖性,而且存在距离模糊问题,传统空时自适应处理(STAP)方法在距离依赖和距离模糊同时存在时难以有效实现杂波补偿和杂波抑制。针对距离模糊下的机载雷达杂波抑制问题,该文提出一种基于频率分集阵列STAP雷达的距离模糊杂波分离与抑制方法。该方法利用频率分集阵列发射导向矢量的距离角度2维依赖性,通过空间频率域子空间投影实现距离模糊杂波的分离,然后对分离后的杂波分别进行距离依赖补偿,最终实现无模糊区域和模糊区域的杂波抑制和运动目标检测。仿真实验验证了该文方法的有效性。 相似文献