共查询到18条相似文献,搜索用时 62 毫秒
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《计算机应用与软件》2014,(8)
非正侧视条件下,机载相控阵雷达的杂波随距离变化而不断改变,各距离单元的回波不再是独立同分布(ⅡD)的数据,由于没有足够多的均匀样本来估计协方差矩阵,使得STAP算法的性能急剧下降。研究非正侧视阵列机载雷达的杂波抑制问题,提出一种改进的多普勒补偿方法以改善非正侧视阵列杂波的非均匀程度。该方法先采用DW处理,使得各距离的杂波谱在主波束方向重合,然后在各多普勒通道内使得待补偿单元的空间角频率与待检测单元的空间角频率相同,从而提高杂波的相似程度。仿真结果表明,所提出的方法杂波抑制性能明显好于DW法和ADC法,但运算量与原有算法大体相当,具有工程应用价值。 相似文献
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机载雷达级联降维空时自适应杂波抑制方法 总被引:1,自引:1,他引:0
提出一种机载雷达杂波抑制的级联降维空时自适应算法,即,先对全空时两维接收数据进行预滤波处理,将杂波局域化,降低杂波自由度;然后对预处理输出的信号的相关矩阵进行子阵划分,求解低维权向量,进一步降低运算量和采样要求。理论分析和实验仿真结果表明,所提算法具有良好的收敛性能和杂波抑制能力,并且对于阵元随机幅相误差和杂波起伏具有很好的容差能力。基于实测数据的实验验证了算法的有效性和稳健性。 相似文献
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多普勒频移问题是高速铁路GSM-R无线通信系统需要解决的难点之一,传统的数据辅助算法虽然精度高,但频移估计范围小,在频移估计范围和频移估计精度两者之间很难达到合理平衡;针对高速铁路特殊场景,文章在改进Fitz算法的基础上,采用一种联合估计方法来进行频移估计;首先由车载信息预先估算出频移,并且进行补偿,再利用改进Fitz算法进行第二次频移估计计算;通过Matlab对联合估计方法进行仿真分析,结果表明该方法在增大了估计范围的同时,提高了估计精度,并且运算复杂度低。 相似文献
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分析了共形阵机载雷达的杂波非平稳特性,并结合该特性提出了一种非平稳杂波环境下的Doppler补偿方法.不同于传统的线阵天线,共形阵天线的三维空间结构决定了应在四维频域研究其杂波分布.针对这个特点,对共形阵机载雷达的杂波非平稳特性进行了理论分析,揭示了共形阵杂波非平稳现象的本质机理,并得出在任意摆放姿态下共形阵机载雷达均存在杂波非平稳现象这一结论.在此基础上,提出了在四维频域对主杂波进行联合补偿的空时自适应处理(space-time adaptive processing,STAP)方法.经仿真验证,在共形阵机载雷达非平稳杂波环境下,利用本文所提STAP方法的杂波抑制性能显著优于传统的Doppler补偿STAP方法. 相似文献
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针对MMV和IRST两种传感器各自的探测特性,提出一种测量方程中含有多普勒频移信息的非线性滤波算法;建立了基于该算法的弹载MMV/IRST复合制导仿真流程,并进行了仿真验证,仿真结果表明该算法能够有效地提高跟踪滤波精度,使导弹精确地完成制导。 相似文献
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机载前视阵雷达近程不同距离门杂波的方位-多普勒分布不同,导致杂波具有强烈的距离依赖性,从而使得杂波噪声协方差矩阵估计不准确,空时自适应处理(STAP)的杂波抑制性能严重下降。针对该问题,提出了一种全谱域的杂波距离依赖性补偿方法。以雷达先验参数知识为基础重构各距离门的杂波协方差矩阵,对重构的杂波协方差矩阵向参考距离门进行一定变换,进而实现全谱域的补偿。仿真实验结果证明了该方法的有效性。 相似文献
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双基机载雷达的杂波存在严重的距离依赖性,从距离上获得的样本不能够准确估计杂波加噪声协方差矩阵,从而导致空时自适应处理(STAP)的杂波抑制性能严重下降。针对该问题,提出了利用直接数据域(DDD)的双基机载雷达地面动目标检测方法。因为DDD算法是在单个距离门对目标滤除后进行空时平滑来获得足够多的样本,所以不需要对双基雷达杂波距离依赖性进行补偿。仿真实验验证了该方法的有效性。 相似文献
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For airborne radar,there are usually insufficient independent and identically distributed(IID)training data because of geometric considerations and terrain variations.The rank reduction technique is one of the most effective approaches to circumvent this problem.In this study,we investigate four reduced-rank spacetime adaptive detectors for airborne radar,namely,the reduced-rank sample-matrix-inversion(RR-SMI),the reduced-rank adaptive matched filter(RR-AMF),the reduced-rank adaptive coherence estimator(RR-ACE),and the reduced-rank generalized likelihood ratio test(RR-GLRT).Their asymptotic analytical probabilities of detection(PD’s)and false alarm(PFA’s)are all derived.These detectors all asymptotically attain a constant false alarm rate(CFAR).It is shown that these four reduced-rank detectors exhibit detection performance which is better than or comparable to that of two existing reduced-rank detectors,proposed by Reed and Gau(RG1and RG2).Moreover,these four reduced-rank detectors are more robust to change in power of clutter and noise than RG1 and RG2. 相似文献
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XU Jia PENG Yingning WAN Qun WANG Xiutan & XIA Xianggen . Department of Electronic Engineering Tsinghua University Beijing China . Department of ECE University of Delaware Newark DE USA 《中国科学F辑(英文版)》2004,47(5):577-586
1 Introduction As a kind of effective active sensor, airborne radar may realize detecting, tracking and imaging of targets on the sea, ground or at low altitude[1—4], and it has been widely used both in civil and military areas. Since airborne radar normally works at the look-down mode, the ground clutter is commonly strong, e.g. the clutter-to-noise ratio (CNR) may reach 60—90 dB in some mountainous or urban areas. Meanwhile, the clut-ter Doppler spectrum is center-shifted and width-spre… 相似文献
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XU Jia PENG Yingning WAN Qun ZHANG Liping LIN Yan & XIA Xianggen Department of Electronic Engineering Tsinghua University Beijing China Department of ECE University of Delaware Newark DE USA Correspondence should be addressed to Xu Jia 《中国科学F辑(英文版)》2004,47(6):706-716
In radar target detection, an optimum processor needs to automatically adapt its weights to the environment change. Conventionally, the optimum weights are obtained by substantial independently and identically distributed (i.i.d.) interference samplings, which is not always realistic in an inhomogeneous clutter background of airborne radar. The lack of i.i.d. samplings will inevitably lead to performance deterioration for optimum processing. In this paper, a novel parametric adaptive processing method is proposed for airborne radar target detection based on the modified Doppler distributed clutter (DDC) model with contribution of clutter's internal motion. It is different from the conventional methods in that the adaptive weights are determined by two parameters of DDC model, i.e., angular center and spread. A low-complexity nonlinear operators approach is also proposed to estimate these parameters. Simulation and performance analysis are also provided to show that the proposed method can remarkably redu 相似文献
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一般的多普勒后处理方法忽视了相邻多普勒通道间数据的相关性,这将造成杂波协方差矩阵估计的不准,因此本文提出了一种联合相邻多普勒通道信息的空时自适应处理方法.该方法先通过时域滑窗后滤波的处理方式来降低杂波的自由度,再利用相邻多普勒门上数据相关性进行联合处理,最终构造出新的杂波协方差矩阵.该方法在提高时域自适应能力的同时减轻了空域杂波相消的负担,提高了处理器的性能,并消除因信息泄露带来的影响,以达到有效抑制地杂波的目的.通过对仿真和实测数据处理,证明了该方法的有效性. 相似文献