复合高斯杂波下抑制失配信号的自适应检测器
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摘要
随着雷达分辨率的提高及擦地角的减小,海杂波幅度分布明显偏离瑞利分布,表现出很强的非高斯特性,复合高斯模型得到广泛应用。因此该文以复合高斯杂波为背景,研究当信号发生失配时的雷达目标检测问题。该文基于两步广义似然比(GLRT)检验,设计了复合高斯杂波下对失配信号具有选择性的自适应检测器。为了设计选择性检测器,在零假设下引入虚假干扰以修正原始二元假设,并假设该虚假干扰与实际目标信号在白化空间正交。该文提出的检测器对海杂波纹理分量及协方差矩阵恒虚警(CFAR)。最后利用仿真及实测海杂波数据,通过蒙特卡洛实验验证该检测器的有效性。实验表明,该文所提检测器有效提高了对失配信号的选择性,同时对距离扩展目标匹配信号的检测性能也有1～3 dB的提升。
Because of the improvement in radar resolution and decrease in grazing angle, the amplitude distribution of sea clutter obviously deviates from the Rayleigh distribution and presents a significant nonGaussian feature. In this case, the compound Gaussian model is widely used. This study investigates the problem of detecting a target when signal mismatches occur in compound Gaussian clutter and proposes a selective detector to reject mismatched signals embedded in compound Gaussian clutter based on the so-called two-step Generalized Likelihood Ratio Test(GLRT). To design the selective detector, we modified the original hypothesis test by injecting a fictitious interference under the null hypothesis. These unwanted signals are assumed to be orthogonal to the nominal steering vector in the whitened subspace. The proposed detector has a Constant False Alarm Rate(CFAR) with respect to the statistics of the texture and covariance matrix. Finally,to demonstrate the effectiveness of the proposed detector, a Monte Carlo simulation is conducted to assess its performance based on the simulated and measured sea clutter data. The experimental results show that the proposed detector effectively improves the selectivity of the mismatched signals together with the detection of matched signals in a range spread target of 1～3 dB.
Because of the improvement in radar resolution and decrease in grazing angle, the amplitude distribution of sea clutter obviously deviates from the Rayleigh distribution and presents a significant nonGaussian feature. In this case, the compound Gaussian model is widely used. This study investigates the problem of detecting a target when signal mismatches occur in compound Gaussian clutter and proposes a selective detector to reject mismatched signals embedded in compound Gaussian clutter based on the so-called two-step Generalized Likelihood Ratio Test(GLRT). To design the selective detector, we modified the original hypothesis test by injecting a fictitious interference under the null hypothesis. These unwanted signals are assumed to be orthogonal to the nominal steering vector in the whitened subspace. The proposed detector has a Constant False Alarm Rate(CFAR) with respect to the statistics of the texture and covariance matrix. Finally,to demonstrate the effectiveness of the proposed detector, a Monte Carlo simulation is conducted to assess its performance based on the simulated and measured sea clutter data. The experimental results show that the proposed detector effectively improves the selectivity of the mismatched signals together with the detection of matched signals in a range spread target of 1～3 dB.
引文
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[7]XU Shuwen,XUE Jian,and SHUI Penglang.Adaptive detection of range-spread targets in compound Gaussian clutter with the square root of inverse Gaussian texture[J].Digital Signal Processing,2016,56:132-139.doi:10.1016/j.dsp.2016.06.009.
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[10]DONG Y.Optimal coherent radar detection in a K-distributed clutter environment[J].IET Radar,Sonar&Navigation,2012,6(5):283-292.doi:10.1049/iet-rsn.2011.0273.
[11]SHUI Penglang,LIU Ming,and XU Shuwen.Shapeparameter-dependent coherent radar target detection in K-distributed clutter[J].IEEE Transactions on Aerospace and Electronic Systems,2016,52(1):451-465.doi:10.1109/TAES.2015.140109.
[12]PULSONE N B and RADER C M.Adaptive beamformer orthogonal rejection test[J].IEEE Transactions on Signal Processing,2001,49(3):521-529.doi:10.1109/78.905870.
[13]BANDIERA F,BESSON O,and RICCI G.An ABORT-like detector with improved mismatched signals rejection capabilities[J].IEEE Transactions on Signal Processing,2008,56(1):14-25.doi:10.1109/TSP.2007.906690.
[14]LIU Weijian,LIU Jun,DU Qinglei,et al.Distributed targetdetection in partially homogeneous environment when signal mismatch occurs[J].IEEE Transactions on Signal Processing,2018,66(14):3918-3928.doi:10.1109/TSP.2018.2841860.
[15]RANGASWAMY M,WEINER D D,and OZTURK A.Non-Gaussian random vector identification using spherically invariant random processes[J].IEEE Transactions on Aerospace and Electronic Systems,1993,29(1):111-124.doi:10.1109/7.249117.
[16]YAO K.A representation theorem and its applications to spherically-invariant random processes[J].IEEETransactions on Information Theory,1973,19(5):600-608.doi:10.1109/TIT.1973.1055076.
[17]RICHMOND C D.Performance of a class of adaptive detection algorithms in nonhomogeneous environments[J].IEEE Transactions on Signal Processing,2000,48(5):1248-1262.doi:10.1109/78.839973.
[18]RICHMOND C D.Statistics of adaptive nulling and use of the generalized eigenrelation(GER)for modeling inhomogeneities in adaptive processing[J].IEEETransactions on Signal Processing,2000,48(5):1263-1273.doi:10.1109/78.839974.
[19]CONTE E and DE MAIO A.Mitigation techniques for nonGaussian sea clutter[J].IEEE Journal of Oceanic Engineering,2004,29(2):284-302.doi:10.1109/JOE.2004.826901.
[20]CONTE E,LOPS M,and RICCI G.Adaptive matched filter detection in spherically invariant noise[J].IEEE Signal Processing Letters,1996,3(8):248-250.doi:10.1109/97.511809.
[2]ROBEY F C,FUHRMANN D R,KELLY E J,et al.ACFAR adaptive matched filter detector[J].IEEETransactions on Aerospace and Electronic Systems,1992,28 (1):208-216.doi:10.1109/7.135446.
[3]DE MAIO A.Rao test for adaptive detection in Gaussian interference with unknown covariance matrix[J].IEEETransactions on Signal Processing,2007,55(7):3577-3584.doi:10.1109/TSP.2007.894238.
[4]CONTE E,DE MAIO A,and RICCI G.GLRT-based adaptive detection algorithms for range-spread targets[J].IEEE Transactions on Signal Processing,2001,49(7):1336-1348.doi:10.1109/78.928688.
[5]GINI F and GRECO M.Texture modelling,estimation and validation using measured sea clutter data[J].IEEProceedings-Radar,Sonar and Navigation,2002,149(3):115-124.doi:10.1049/ip-rsn:20020272.
[6]SANGSTON K J,GINI F,GRECO M V,et al.Structures for radar detection in compound Gaussian clutter[J].IEEETransactions on Aerospace and Electronic Systems,1999,35(2):445-458.doi:10.1109/7.766928.
[7]XU Shuwen,XUE Jian,and SHUI Penglang.Adaptive detection of range-spread targets in compound Gaussian clutter with the square root of inverse Gaussian texture[J].Digital Signal Processing,2016,56:132-139.doi:10.1016/j.dsp.2016.06.009.
[8]SHANG Xiuqin,SONG Hongjun,WANG Yu,et al.Adaptive detection of distributed targets in compoundGaussian clutter with inverse gamma texture[J].Digital Signal Processing,2012,22(6):1024-1030.doi:10.1016/j.dsp.2012.05.002.
[9]SANGSTON K J,GINI F,and GRECO M S.Coherent radar target detection in heavy-tailed compound-Gaussian clutter[J].IEEE Transactions on Aerospace and Electronic Systems,2012,48(1):64-77.doi:10.1109/TAES.2012.6129621.
[10]DONG Y.Optimal coherent radar detection in a K-distributed clutter environment[J].IET Radar,Sonar&Navigation,2012,6(5):283-292.doi:10.1049/iet-rsn.2011.0273.
[11]SHUI Penglang,LIU Ming,and XU Shuwen.Shapeparameter-dependent coherent radar target detection in K-distributed clutter[J].IEEE Transactions on Aerospace and Electronic Systems,2016,52(1):451-465.doi:10.1109/TAES.2015.140109.
[12]PULSONE N B and RADER C M.Adaptive beamformer orthogonal rejection test[J].IEEE Transactions on Signal Processing,2001,49(3):521-529.doi:10.1109/78.905870.
[13]BANDIERA F,BESSON O,and RICCI G.An ABORT-like detector with improved mismatched signals rejection capabilities[J].IEEE Transactions on Signal Processing,2008,56(1):14-25.doi:10.1109/TSP.2007.906690.
[14]LIU Weijian,LIU Jun,DU Qinglei,et al.Distributed targetdetection in partially homogeneous environment when signal mismatch occurs[J].IEEE Transactions on Signal Processing,2018,66(14):3918-3928.doi:10.1109/TSP.2018.2841860.
[15]RANGASWAMY M,WEINER D D,and OZTURK A.Non-Gaussian random vector identification using spherically invariant random processes[J].IEEE Transactions on Aerospace and Electronic Systems,1993,29(1):111-124.doi:10.1109/7.249117.
[16]YAO K.A representation theorem and its applications to spherically-invariant random processes[J].IEEETransactions on Information Theory,1973,19(5):600-608.doi:10.1109/TIT.1973.1055076.
[17]RICHMOND C D.Performance of a class of adaptive detection algorithms in nonhomogeneous environments[J].IEEE Transactions on Signal Processing,2000,48(5):1248-1262.doi:10.1109/78.839973.
[18]RICHMOND C D.Statistics of adaptive nulling and use of the generalized eigenrelation(GER)for modeling inhomogeneities in adaptive processing[J].IEEETransactions on Signal Processing,2000,48(5):1263-1273.doi:10.1109/78.839974.
[19]CONTE E and DE MAIO A.Mitigation techniques for nonGaussian sea clutter[J].IEEE Journal of Oceanic Engineering,2004,29(2):284-302.doi:10.1109/JOE.2004.826901.
[20]CONTE E,LOPS M,and RICCI G.Adaptive matched filter detection in spherically invariant noise[J].IEEE Signal Processing Letters,1996,3(8):248-250.doi:10.1109/97.511809.