共形阵列误差校正方法研究

发布时间：2018-12-14 22:40

【摘要】：共形阵列天线是与物体外形保持一致的天线阵。相比传统平面阵列,共形阵列不仅要满足天线本身的性能要求,还要兼顾载体的气动特性。正是由于共形阵列这样的优势,所以共形阵列被广泛地用在雷达、通信及导航等相关领域。在平面阵列中,阵列误差的存在将会严重影响空间谱估计性能。这时,我们可以通过一些经典的算法进行误差校正。而在共形阵列中,阵元方向图差异性的存在将导致传统平面阵列的阵列误差校正算法不适用的情况。因此,研究共形阵列的误差校正方法具有重要意义。本文针对两种不同结构的共形阵列,阵列误差存在时,提出了两种阵列误差校正算法以实现对信源角度的精确估计。论文的主要内容包括：首先,建立了平面阵列的信号模型,并详细地描述了均匀线阵和均匀圆阵这两种平面阵列的基本特点。同时也建立了共形阵列的信号模型以及阵列误差模型,并通过实验对阵列误差的影响进行分析以及验证了两种经典的阵列误差校正算法即有源校正法和自校正法的有效性。其次,提出了一种基于圆环共形阵列多种误差存在下有源校正算法。这里,多种误差包括阵元幅相误差、阵元互耦误差及阵元位置误差,并将这些误差等效为方位依赖的阵元幅相误差。在算法中,通过子阵分割将整个阵列和相应的空域分割成若干个子阵以及相对应的子空域,解决了共形阵列的遮蔽效应。在每个子空域范围内,设置若干个辅助信源并利用有源校正法得到方位依赖的误差系数,并重构出每个子阵的真实阵列流型矩阵。基于重构的阵列流型矩阵,可以实现对信源角度的精确估计。仿真实验验证了算法的优越性能。最后,提出了一种基于圆柱共形阵列互耦误差存在下自校正算法。算法是通过降维的思想,将二维波达方向(DOA)估计变成两个一维DOA估计即信源俯仰角估计和信源方位角估计,并分别利用旋转不变子空间(ESPRIT)算法和秩损法(RARE)实现对信源的俯仰角估计和方位角估计。通过信源角度的估计值可以实现对阵元互耦系数的估计。仿真实验验证了此阵列误差校正算法的有效性。
[Abstract]:Conformal array antenna is an antenna array which is consistent with the shape of object. Compared with traditional planar arrays, conformal arrays should not only meet the performance requirements of the antenna itself, but also give consideration to the aerodynamic characteristics of the carrier. Because of the advantages of conformal arrays, conformal arrays are widely used in radar, communication, navigation and other related fields. In planar array, the existence of array error will seriously affect the performance of spatial spectrum estimation. At this point, we can use some classical algorithms for error correction. In conformal array, the difference of array element pattern will lead to the inapplicability of traditional array error correction algorithm. Therefore, it is of great significance to study the error correction method of conformal array. In this paper, for two conformal arrays with different structures, two kinds of array error correction algorithms are proposed to accurately estimate the source angle when array errors exist. The main contents of this paper are as follows: firstly, the signal model of planar array is established, and the basic characteristics of uniform linear array and uniform circular array are described in detail. At the same time, the signal model and array error model of conformal array are established, and the effect of array error on array error is analyzed through experiments. The effectiveness of two classical array error correction algorithms, active correction method and self-tuning method, is verified. Secondly, an active correction algorithm based on various errors of circular conformal array is proposed. Here, many kinds of errors include array element amplitude-phase error, array element mutual coupling error and array element position error, and these errors are equivalent to azimuth dependent array element amplitude and phase errors. In the algorithm, the whole array and the corresponding spatial domain are divided into several subarrays and corresponding subdomains by subarray segmentation, which solves the shadowing effect of conformal arrays. In each subdomain, several auxiliary sources are set up and the azimuth dependent error coefficients are obtained by using active correction method, and the real array flow pattern matrix of each subarray is reconstructed. Based on the reconstructed array flow pattern matrix, the accurate estimation of the source angle can be realized. Simulation results show the superiority of the algorithm. Finally, a self-tuning algorithm based on the mutual coupling error of cylindrical conformal arrays is proposed. Based on the idea of dimension reduction, the two-dimensional DOA (DOA) estimation is transformed into two one-dimensional DOA estimators, namely, the source pitch angle estimation and the source azimuth estimation. The rotation invariant subspace (ESPRIT) algorithm and rank loss method (RARE) are used to estimate the pitch angle and azimuth angle of the source, respectively. The mutual coupling coefficient can be estimated by estimating the source angle. Simulation results show the effectiveness of the algorithm.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN820.15

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