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1、中文翻译：自适应共形雷达阵 共形阵列天线雷达应用的优点包括最小载荷重量,增加视野不需要繁琐的机械耦合和旋转接头,和易于集成不同的传感器功能。此外共形阵列的设计避免了信号调制由于天线旋转不利的影响干扰取消和目标匹配滤波。这些优势支持增强雷达部署无人机(uav),升级现有系统,新一代传感器的应用。 共形阵列雷达设计师也存在挑战。旁瓣水平升高,会有有害杂波和干扰对检测性能的影响。根据配置不同,数组的偏振响应可以出现不均匀。最后，数组的一般非线性特性导致杂波非平稳,从而使必要的自适应杂波的实现缓解阶段。这里,我们检查移动目标信号的自适应检测性能潜力(MTI)雷达采用共形天线阵。我们报告的结果两个候选人
2、保形设计采取以下形状:锥形,独木舟和雷达天线罩的形状。我们的发现表明阵列非线性和定向诱导杂波非平稳;这种不稳定杂乱影响时空适应性处理(堵塞)实现必要的有效的地面杂波抑制。因此,我们将重点介绍一些缓和的解决方案。 大多数的共形阵列文献处理合成。各种迭代技术用于将传感器放在保形表面由于某些限制的辐射模式。旁瓣优化特殊类的共形阵列也被利益的一个话题。循环数组堵塞的特殊情况也较为详细地研究。我们组织的其余部分本文以以下方式。节我们介绍一些重要的堵塞结果与当前的应用程序。节讨论重要问题有关信号建模、定义性能指标,并提供假设导致我们的仿真结果。随后,节我们分析的性能潜力两个正形通过数值模拟设计。本文主要结
3、论报告包括以下:杂波非平稳归因于共形阵列的设计会导致大量的检测性能下降,4到10 dB的额外损失的均质条件。这损失发生在陡峭的萧条的角度,如预期。本地化处理提高了性能由几个分贝。结合本地化处理权重提高能力通过大量探测空间的一部分。例如,这个解决方案可以完全恢复损失由于非平稳在中间范围或适度的抑郁症的角度。然而,改种持续与陡峭的抑郁症相关的范围角度。自适应雷达基本原理优势在电子扫描相控阵天线系统和数字信号处理技术使部署先进的算法,如堵塞。堵塞是一个关键组成部分薄弱或缓慢的从航空航天雷达目标检测平台。基本理论和机制实施到位,研究人员最近关注提高实用堵塞性能并考察其不同的应用程序。 STAP是一个多
4、维的data-domain实现最优的滤波器。其建设需要协方差矩阵估计和转向向量假说作为相应代理人未知的数量。通常采用样本协方差矩阵, Rk = (1)代替未知的clutter-plus-noise协方差矩阵,描述二阶,null-hypothesis(H0)统计数据的时空快照xk,k范围对应单元。Rk是一种最大似然估计(MLE)的Rk,x当辅助数据,是多元高斯和独立和恒等分布的(iid)关于x,自适应权向量然后,=,是一个常数,是假设时空转向向量,是一个常数,精确的目标操舵向量。实现协方差估计的足够的忠诚是一个阻止实现的关键;range-varying混乱特征异构带来的混乱和传感器geometr
5、y-induced非平稳影响的准确性。异构的混乱是由于不断变化的文化特征在范围和角度,而不是进一步的兴趣。传感器几何影响空间传播信号的采样和可能导致非平稳的时空混乱的反应在训练数据集。具体地说,许多堵塞分析考虑均匀线性阵列(ULA)”在侧视配置方便和避免并发症的发生与替代我的配置。侧视齿龈确保良性杂乱angle-Doppler响应常数行为对所有感兴趣的范围。一个常数有关空间和多普勒频率在整个范围的程度。鉴于均匀杂波条件下,渐近协方差矩阵估计收敛的精确值。众所周知,显然其他简单的配置产生某种程度的非平稳:前瞻性数组展品angle-Doppler变化在这些地区在这里倾斜范围平台高度的比率小于5,而
6、倾斜的数组遭受angle-Doppler失调。英文原文：Adaptive Conformal Array RadarAdvantages of conformal array antennas for radar application include minimal payload weight ,increased field of view without the need for cumbersome mechanical couplings and rotary joints, and ease of integration with diverse sensor function
7、. Additionally the conformal array design avoids signal modulation due to antenna rotation that adverse affects interference cancellation and target matched filtering . These advantages support enhanced radar deployment on unmanned aerial vehicles(UAVs),upgrades to existing systems,and next-generati
8、on sensor applications.Conformal arrays also present challenges to the radar designer.Elevated sidelobe levels exacerbate the already deleterious impact of clutter and jamming on detection performance. Depending on the configuration,the arrays polarimetric response can appear non-uniform.Finally, th
9、e arrays generally nonlinear characteristic induces clutter nonstationarity, thereby complicating the implementation of the requisite adaptive clutter mitigation stage.Herein ,we examine the adaptive detection performance potential of moving target indication (MTI) radar employing a conformal antenn
10、a array .We report results for two candidate conformal designs taking the following shape : tapered ,belly-mounted canoe and chined radome shape . Our findings indicate that array nonlinearity and orientation induce clutter nonstationarity ; this nonstationary behavior-defined by range-varying clutt
11、er statistics-adversely affects space-time adaptive processing (STAP) implementations essential to effective ground clutter suppression .Consequently, we highlight some mitigating solutions.The majority of the conformal array literature has dealt with radiation-pattern synthesis. A variety of iterat
12、ive techniques are used to place sensors on a conformal surface given certain constraints on the radiation pattern .Sidelobe optimization for special classes of conformal arrays has also been a topic of interests .The special case of circular array STAP has also been studied in some detail . We orga
13、nize the remainder of this paper in the following manner .In Section we highlight some important STAP results relating to the current application .Section discusses important issues relating to signal modeling ,defines performance metrics , and provides assumptions leading to our simulation results
14、.Subsequently , in Section we analyze the performance potential of the two conformal designs via numerical simulation.Key findings reported in this paper include the following : Clutter nonstationarity attributable to the conformal array design leads to substantial detection performance degradation
15、,on the order of 4-10 dB of additional loss from the homogeneous condition . Much of this loss occurs at the steeper depression angles ,as expected . Localized processing improves performance by several decibels. Combining localized processing with timevarying weights enhances capability by substant
16、ial amounts over part of the detection space. For example , this solution can fully recover loss due to nonstationarity at intermediate ranges or modest depression angles . However , lossers persist for those ranges associated with steeper depression angles.Adaptive RADAR Fundamentals Advantages in
17、electronically scanned phased-array antenna systems and digital signal processing technology enable the deployment of advanced algorithms ,such as STAP. STAP is a critical component of weak or slow-moving target detection from aerospace radar platforms.With foundational theory and mechanisms for imp
18、lementation in place ,researchers have recently focused on improving practical STAP performance and examining its diverse applications. STAP is a data-domain implementation of a multidimensional optimal filter . Its construction requires a covariance matrix estimate and a steering vector hypothesis
19、as surrogates for the corresponding unknown quantities . It is common to employ the sample covariance matrix,Rk = (1)in lieu of the unknown clutter-plus-noise covariance matrix Rk , characterizing the second-order, null-hypothesis (H0) statistics of the space-time snapshot xk ,corresponding to the k
20、 range cell . Rk represents a maximum likelihood estimate (MLE) of Rk ,xwhen the secondary data ,are multivariate Gaussian and independent and identically distributed (iid) with respect to x,The adaptive weight vector then follow as ,=,where , is a constant and is the hypothesized space-time steerin
21、g vector , =, where is a constant and is the precise target steering vector. Achieving a covariance estimate of adequate fidelity is a crux of the STAP implementation ; range-varying clutter characteristics resulting from heterogeneous clutter and sensor geometry-induced nonstationarity affect the a
22、ccuracy of . Heterogeneous clutter is a result of changing cultural characteristics over range and angle and is not of further interest in this paper .Sensor geometry affects spatial sampling of the propagating signal and can lead to a nonstationary space-time clutter response over the training data
23、 set . Specifically , many STAP analyses consider a uniform linear array (ULA ) in a side-looking configuration as a matter of both convenience and to avoid complications occurring with alternate my configurations . The side-looking ULA ensures a benign clutter angle-Doppler response of constant beh
24、avior over all ranges of interest . A single constant relates spatial and Doppler frequencies over the entire range extent . Given homogeneous clutter conditions , the asymptotic covariance matrix estimate converges to the precise value of . It is knownthat other apparently simple configurations induce some degree of nonstationarit-y : the forward-looking array exhibits angle-Doppler variation over those regio-ns here the ratio of slant range to platform height is less than five ,whilst ca-nted arrays suffer from angle-Doppler misalignment as well.