Adaptive detection of range-spread targets is considered in the presence of subspace interference plus Gaussian clutter with unknown covariance matrix.The target signal and interference are supposed to lie in two line...Adaptive detection of range-spread targets is considered in the presence of subspace interference plus Gaussian clutter with unknown covariance matrix.The target signal and interference are supposed to lie in two linearly independent subspaces with deterministic but unknown coordinates.Relying on the two-step criteria,two adaptive detectors based on Gradient tests are proposed,in homogeneous and partially homogeneous clutter plus subspace interference,respectively.Both of the proposed detectors exhibit theoretically constant false alarm rate property against unknown clutter covariance matrix as well as the power level.Numerical results show that,the proposed detectors have better performance than their existing counterparts,especially for mismatches in the signal steering vectors.展开更多
随着数字射频存储器(digital ratio frequency memory,DRFM)的成熟发展与广泛应用,基于DRFM的相干转发干扰成为当前雷达干扰技术的主流。相干转发干扰具有转发效率高、相干性强等突出优势,并且在数字域的处理算法灵活高效,能够产生复杂...随着数字射频存储器(digital ratio frequency memory,DRFM)的成熟发展与广泛应用,基于DRFM的相干转发干扰成为当前雷达干扰技术的主流。相干转发干扰具有转发效率高、相干性强等突出优势,并且在数字域的处理算法灵活高效,能够产生复杂多样的干扰效果。但经过大量实践发现,当需要产生大范围连片干扰效果时,若干扰机采用密集转发,不但使DRFM运算量急剧增加,而且会破坏恒模约束,导致干扰机功放效率严重下降。基于该情况,本文提出了线性调频(linear frequency modulation,LFM)雷达信号的拉伸变换干扰方法:在数字域对雷达信号的脉宽、带宽分别压缩、展宽,即拉伸变换,再将其辐射至雷达接收机。拉伸信号经匹配滤波处理后,会呈现大范围连片相干干扰效果,干扰效果受拉伸变换因子影响,灵活可调,且拉伸变换干扰满足恒模约束。展开更多
针对复杂环境下猫眼目标探测易受环境干扰、特征区分度不足等问题,提出一种基于空间上下文的决策级融合猫眼目标检测算法(Decision-level Fusion based on Spatial Context,DFSC)。算法由三个模块组成:在猫眼目标检测模块中,提出基于自...针对复杂环境下猫眼目标探测易受环境干扰、特征区分度不足等问题,提出一种基于空间上下文的决策级融合猫眼目标检测算法(Decision-level Fusion based on Spatial Context,DFSC)。算法由三个模块组成:在猫眼目标检测模块中,提出基于自适应迭代最大类间方差的图像二值化方法,结合迭代前景细化策略和动态收敛机制,在精确提取猫眼目标连通域的同时保留局部细节信息;构建了傅里叶功率谱和归一化加权质心偏移特征描述子,提升猫眼与干扰目标的可区分性;提出基于自适应环境感知的多维特征加权融合方法,实现特征权重的自适应优化。在通用目标检测模块中,将可变形卷积DCNv3引入YOLOv8骨干网络的C2f模块,提升对遮挡目标和小目标的检测性能。在基于空间上下文的决策级融合模块中,通过计算猫眼目标的遮挡率来评估其与环境干扰目标的空间关系,从而有效抑制虚警。在基于自主研发的激光主动探测系统构建的猫眼目标检测数据集上开展实验,结果表明,与现有主流算法相比,召回率由92.2%提升至98.9%,精度由49.0%提升至74.5%,单帧耗时8.3 ms,显著降低了算法在复杂环境下的虚警率。展开更多
A switching variability index （SVl） constant false alarm rate （CFAR） detector is proposed for improving the detection performance of VI-CFAR detectors in multiple targets backgrounds. When the presence of non-homo...A switching variability index （SVl） constant false alarm rate （CFAR） detector is proposed for improving the detection performance of VI-CFAR detectors in multiple targets backgrounds. When the presence of non-homogeneity in CFAR reference windows is indicated by a VI-CFAR detector, a switching- CFAR detector is introduced to optimize the performance of the VI-CFAR detector in homogeneous, multiple targets and clutter edge backgrounds. The structure and parameters selection method of the SVI-CFAR detector is presented. Comparisons with classic CFAR detectors and recently proposed detectors are also given. Theoretical analysis and simulation results show that SVICFAR detector maintains the good performance of the VI-CFAR detector in homogeneous and clutter edge backgrounds, while greatly improving the capacity of anti-multi targets.展开更多
The traditional clutter map constant false alarm rate (CM-CFAR) detector is affected by interference and self-masking[1] which will cause the low probability of detection. To solve these problems, a novel algorithm na...The traditional clutter map constant false alarm rate (CM-CFAR) detector is affected by interference and self-masking[1] which will cause the low probability of detection. To solve these problems, a novel algorithm named clutter map CFAR with amplitude limiter (ALCM-CFAR) is proposed, in which the amplitude of the input signal is limited by a filter. The simulation results prove the effectiveness of ALCM-CFAR algorithm.展开更多
基金supported by the National Natural Science Foundation of China(61971432)Taishan Scholar Project of Shandong Province(tsqn201909156)the Outstanding Youth Innovation Team Program of University in Shandong Province(2019KJN031)。
文摘Adaptive detection of range-spread targets is considered in the presence of subspace interference plus Gaussian clutter with unknown covariance matrix.The target signal and interference are supposed to lie in two linearly independent subspaces with deterministic but unknown coordinates.Relying on the two-step criteria,two adaptive detectors based on Gradient tests are proposed,in homogeneous and partially homogeneous clutter plus subspace interference,respectively.Both of the proposed detectors exhibit theoretically constant false alarm rate property against unknown clutter covariance matrix as well as the power level.Numerical results show that,the proposed detectors have better performance than their existing counterparts,especially for mismatches in the signal steering vectors.
文摘随着数字射频存储器(digital ratio frequency memory,DRFM)的成熟发展与广泛应用,基于DRFM的相干转发干扰成为当前雷达干扰技术的主流。相干转发干扰具有转发效率高、相干性强等突出优势,并且在数字域的处理算法灵活高效,能够产生复杂多样的干扰效果。但经过大量实践发现,当需要产生大范围连片干扰效果时,若干扰机采用密集转发,不但使DRFM运算量急剧增加,而且会破坏恒模约束,导致干扰机功放效率严重下降。基于该情况,本文提出了线性调频(linear frequency modulation,LFM)雷达信号的拉伸变换干扰方法:在数字域对雷达信号的脉宽、带宽分别压缩、展宽,即拉伸变换,再将其辐射至雷达接收机。拉伸信号经匹配滤波处理后,会呈现大范围连片相干干扰效果,干扰效果受拉伸变换因子影响,灵活可调,且拉伸变换干扰满足恒模约束。
文摘针对复杂环境下猫眼目标探测易受环境干扰、特征区分度不足等问题,提出一种基于空间上下文的决策级融合猫眼目标检测算法(Decision-level Fusion based on Spatial Context,DFSC)。算法由三个模块组成:在猫眼目标检测模块中,提出基于自适应迭代最大类间方差的图像二值化方法,结合迭代前景细化策略和动态收敛机制,在精确提取猫眼目标连通域的同时保留局部细节信息;构建了傅里叶功率谱和归一化加权质心偏移特征描述子,提升猫眼与干扰目标的可区分性;提出基于自适应环境感知的多维特征加权融合方法,实现特征权重的自适应优化。在通用目标检测模块中,将可变形卷积DCNv3引入YOLOv8骨干网络的C2f模块,提升对遮挡目标和小目标的检测性能。在基于空间上下文的决策级融合模块中,通过计算猫眼目标的遮挡率来评估其与环境干扰目标的空间关系,从而有效抑制虚警。在基于自主研发的激光主动探测系统构建的猫眼目标检测数据集上开展实验,结果表明,与现有主流算法相比,召回率由92.2%提升至98.9%,精度由49.0%提升至74.5%,单帧耗时8.3 ms,显著降低了算法在复杂环境下的虚警率。
基金supported by the National Natural Science Foundation of China(61102158)the China Postdoctoral Science Foundation(2011M500667)
文摘A switching variability index （SVl） constant false alarm rate （CFAR） detector is proposed for improving the detection performance of VI-CFAR detectors in multiple targets backgrounds. When the presence of non-homogeneity in CFAR reference windows is indicated by a VI-CFAR detector, a switching- CFAR detector is introduced to optimize the performance of the VI-CFAR detector in homogeneous, multiple targets and clutter edge backgrounds. The structure and parameters selection method of the SVI-CFAR detector is presented. Comparisons with classic CFAR detectors and recently proposed detectors are also given. Theoretical analysis and simulation results show that SVICFAR detector maintains the good performance of the VI-CFAR detector in homogeneous and clutter edge backgrounds, while greatly improving the capacity of anti-multi targets.
基金This project was supported by the National Natural Science Foundation of China (60232010).
文摘The traditional clutter map constant false alarm rate (CM-CFAR) detector is affected by interference and self-masking[1] which will cause the low probability of detection. To solve these problems, a novel algorithm named clutter map CFAR with amplitude limiter (ALCM-CFAR) is proposed, in which the amplitude of the input signal is limited by a filter. The simulation results prove the effectiveness of ALCM-CFAR algorithm.
