共查询到19条相似文献,搜索用时 109 毫秒
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在雷达信号检测过程中,为了实现恒虚警处理,必须采用动态门限。恒虚警检测器的门限设置通常是利用待检测单元附近的距离单元杂波数据进行计算得到的。然而,杂波环境的非均匀性导致了杂波功率随着距离变化剧烈,常规的恒虚警检测器性能会显著下降。文中给出了基于地理信息系统的恒虚警检测算法,利用对杂波环境的了解程度,可以显著提高CFAR检测器的性能。利用IPIX雷达实测数据,验证了该算法性能优于常规的其他CFAR处理器。 相似文献
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矩阵CFAR检测器是根据信息几何理论提出的,但其恒虚警特性没有从理论上得到分析,且检测性能也有待进一步提高。该文首先根据矩阵流形上正态律的概念从理论上推导了矩阵CFAR检测器的恒虚警特性,并在此基础上,利用积累性能更好的KLD(Kullback-Leibler Divergence)代替测地线距离,提出了一种改进的矩阵CFAR检测器。最后通过仿真实验验证了改进方法具有更好的检测性能。 相似文献
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基于恒虚警率的门限判决系数寻优研究 总被引:1,自引:0,他引:1
在雷达信号检测系统中,对于一定的检测门限,如果噪声或杂波电平增大一点,虚警率便会大大增加,同时使发现概率降低,这样便降低了雷达系统发现目标的能力,因此在现代雷达信号检测系统中,为了保证一定的发现概率,一般采取恒虚警率(CFAR)处理,在雷达系统进行恒虚警处理时,由于杂波强度可能偏离统计平均值而产生起伏,此时采用理论的门限判决系数将使虚警率大大增加。通过对雷达信号检测恒虚警性能的研究,分析了有限参考单元数对虚警率及发现概率的影响,同时提出一种有效的寻优算法在恒虚警检测中对实际的门限判决系数进行实时的动态寻优,使检测系统始终保持在恒虚警的工作状态中。 相似文献
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CFAR检测器是雷达信号处理机中的重要组成部分。本文对脉冲多普勒雷达信号处理机中的CFAR检测器进行了仿真研究。给出了信号处理机中CFAR检测器的设计方案,对邻近单元平均恒虚警处理中的虚警概率、发现概率和恒虚警处理损失等问题进行了研究。分析了有限的参考单元数对虚警性能的影响,并给出了修正的门限系数。得出了不同参考单元数下的恒虚警损失,及恒虚警损失与相对门限系数之间的关系。得到了一定发现概率下所要求的信号处理机的输入信噪比。研究了信号处理机中其它部分对恒虚警处理性能的影响,如脉冲压缩对虚警率的影响等。 相似文献
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Pareto分布是一种重要的非高斯分布,被证明能够有效描述高分辨率主动声纳的混响统计特性。文章分析了有序统计选小(Ordered Statistic with Smallest Option, OSSO)和有序统计选大(Ordered Statistic with Greatest Option, OSGO)两种恒虚警(Constant Fales Alarm Rate, CFAR)检测器在Pareto分布混响背景下的性能。在尺度参数已知情况下,证明了OSSO-CFAR和OSGO-CFAR对形状参数具有恒虚警的特性。进一步分析了两种检测器在均匀Pareto混响背景、多目标干扰及混响边缘情况下的性能,并与有序统计(Ordered Statistic, OS)CFAR进行了对比。结果表明,在均匀混响背景下,OSGO-CFAR的检测性能与OS-CFAR相近,在混响边缘情况下具有最好的虚警控制能力;而对于多目标干扰情况,OSSO-CFAR比其他两种检测器的检测性能更优。 相似文献
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本文通过分析现有的五种CFAR处理器检测性能的优劣,提出了准有序CFAR方案,并在计算机模拟统计的基础上阐述了该处理器的检测性能,得出POS-CFAR能以较小的检测损失,换取对杂波边界、多目标环境有较好适应性的结论。 相似文献
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等效视数是影响极化合成孔径雷达(PolSAR)图像恒虚警 (CFAR)检测性能的重要参数.目前等效视数的估计大都不是整数,导致已有的基于整数等效视数的CFAR检测方法不再适用.为解决此问题,提出了一种新的PolSAR图像目标CFAR检测解析算法.首先,在Wishart分布假设下,推导出了多视极化白化滤波(MPWF)检测量的概率密度函数;然后对其积分得到了CFAR检测门限关于等效视数的解析表达式;最后通过仿真数据和AIRSAR实测数据比较了新方法与已有的适用于整数等效视数的检测方法和双参数恒虚警(2P-CFAR)检测方法的CFAR检测性能.结果表明新方法中实际虚警概率与给定的恒虚警概率最为接近,更好保证了CFAR检测的恒虚警假设. 相似文献
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PERFORMANCE COMPARISON OF A LINEARLY COMBINED ORDERED-STATISTIC DETECTORS UNDER POSTDETECTION INTEGRATION AND NONHOMOGENEOUS SITUATIONS 总被引:3,自引:0,他引:3
Mohamed Bakry El_Mashade 《电子科学学刊(英文版)》2006,23(5):698-707
Several Constant False Alarm Rate (CFAR) architectures, where radar systems often employ them to automatically adapt the detection threshold to the local background noise or clutter power in an attempt to maintain an approximately constant rate of false alarm, have been recently proposed to estimate the unknown noise power level. Since the Ordered-Statistics (OS) based algorithm has some advantages over the Cell-Averaging (CA) technique, we are concerned here with this type of CFAR detectors. The Linearly Combined Ordered-Statistic (LCOS) processor, which sets threshold by processing a weighted ordered range samples within finite moving window, may actually perform somewhat better than the conventional OS detector. Our objective in this paper is to analyze the LCOS processor along with the conventional OS scheme for the case where the radar receiver incorporates a postdetection integrator amongst its contents and where the operating environments contain a number of secondary interfering targets along with the primary target of concern and the two target types fluctuate in accordance with the Swerling Ⅱ fluctuation model and to compare their performances under various operating conditions. 相似文献
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Mohamed B. El Mashade 《Radioelectronics and Communications Systems》2016,59(12):536-551
The detection of radar targets in a background, the statistical parameters of which are unknown and may not be stationary, can be effectively achieved through CFAR processors. The CA-CFAR scheme performs optimally for homogeneous and exponentially distributed clutter observations. However, it exhibits severe performance degradation in the presence of outlying target returns in the reference set or in regions of abrupt change in the background clutter power. The OS-CFAR processor has been proposed to solve both of these problems. Although this processor may treat target multiplicity quite well, it lacks effectiveness in preventing excessive false alarms during clutter power transitions. The TM-CFAR algorithm, which implements trimmed averaging after ordering, can be considered as a modified version of OS technique. By knowingly trimming the ordered samples, the TM detector may actually perform better than the OS processor. To simultaneously exploit the merits of CA, OS, and TM schemes, two combinations namely CAOS and CATM have been suggested. Each one of these versions optimizes good features of two CFAR detectors, depending on the characteristics of clutter and searched targets, with the goal of enhancing the detection performance under constant level of false alarm. It is realized by parallel operation of two standard types of CFARschemes. Our goal in this paper is to analyze these two developed versions in heterogeneous situations, to show to what extent they can improve the behavior of the conventional CFAR processors. 相似文献
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运用雷达上经典的自适应恒虚警的检测方法,分析红外图像特性,针对红外目标特点,结合FPGA的优势实现对红外视频图像目标的快速检测。兼顾了实时性、处理速度、系统可靠性等要求。外置可调谐式阈值设置,可适应多环境问题。实验结果表现出较好的效果,展现出较高的实用价值。 相似文献
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采用自适应功率回归门限设定的HF雷达舰船探测 总被引:1,自引:0,他引:1
高频(HF)雷达能够探测和跟踪极远距离上的目标。但是,包含外部噪声、各种不同杂波和干扰的信号环境将大大限制探测性能和系统能力。文中研究了一种新方法来解决复杂HF雷达信号环境中的目标探测问题。该方法采用传统的恒虚警率(CFAR)检测方法,但其门限设置是基于沿距离和多普勒单元功率谱值的回归分析。就中,CFAR检测试验规则与局部峰值测量方法相结合。文中所提探测方法已经真实HF雷达数据试验,得到了很有前景的结果。 相似文献
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结合某雷达信号处理机研制项目,对该雷达信号处理机的脉冲压缩、动目标显示和动目标检测、恒虚警处理等软件进行设计。论文首先回顾了该处理机用到的几种雷达信号处理方法:线性调频信号的脉冲压缩、基于一次相消器和二次相消器的动目标显示、通过窄带多普勒滤波器组的动目标检测处理、恒虚警检测等方面的工作原理和实现方式。根据信号处理机硬件平台设计了相关的信号处理软件,并实现上述信号处理功能。 相似文献
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《AEUE-International Journal of Electronics and Communications》2014,68(12):1253-1260
In radar detection, many constant false alarm rate (CFAR) processors have been proposed in the literature. It is well known that a processor is optimal only for one type of environment and that its detection performances are seriously degraded in presence of unknown irregularities. In such situations, the main difficulty resides in the estimation of the background configuration. That is, depending upon the non-homogeneity of the environment, one would choose the adequate optimal detection algorithm among a variety of known conventional ones that offer the best detection probability. Based on unknown transitions; i.e., in the presence of a priori unknown numbers of interfering targets and/or clutter edge, we propose an automatic censoring CFAR (AC-CFAR) detector for heterogeneous Gaussian clutter. The censoring technique used in this work offers a good discrimination between homogeneous and non-homogeneous environments. The proposed detector dynamically switches to the optimal conventional detector CA-, CMLD- or TM-CFAR. The performances of the proposed detector is evaluated and compared to existing detectors in various background situations. Monte Carlo simulations show that the AC-CFAR detector performs like the CA-CFAR in a homogeneous background. Moreover, the proposed detector exhibits considerable robustness in the presence of interfering targets and/or clutter-edge situations. 相似文献