非规则稀疏阵列旁瓣抑制方法研究

发布时间：2019-06-21 14:41

【摘要】：非规则稀疏阵列由于阵元的稀疏布置,增大了天线阵列的孔径,使得其方向性增强,扫描波束变窄,空间分辨率明显提高,同时也大大减弱了阵元间的互耦效应,而非规则性则使该阵列能实现无模糊测角。然而,在实际的布阵环境中存在许多因素会限制布阵的范围,如山川、河流、沼泽等。在阵列构型的研究中,还需要针对这些地理约束提出相应的布阵方法。此外,对于通过处理稀疏阵列的接收信号从而估计信源方向的算法,其测向性能都是基于阵列流形精确己知的前提。但是在实际的工程应用中,真实的阵列流形往往会随着许多因素的变化而出现一定程度的偏差,这将使得测向算法的旁瓣电平升高,严重时甚至超过主瓣。本文对存在地理因素限制下非规则稀疏线阵的阵列构型问题,研究了基于天线尺寸约束与地理环境约束的非规则阵列构型方法。同时针对阵列天线中存在误差影响旁瓣的问题,研究了阵列自校正方法,其主要工作包括以下方面:(1)针对随机稀疏阵列构型问题,给出了非规则稀疏阵列信号模型,并在此基础上设计了稀疏阵列低旁瓣优化布阵的最优化模型,研究了基于模式搜索的无约束的最优阵元配置的方法。进一步地,针对实际布阵环境中存在天线尺寸与地理约束限制的问题,研究了基于粒子群的非规则阵列构型方法。(2)针对实际场景中存在阵列误差条件下的近场窄带信号建模问题,首先,分析了阵列位置误差、接收通道幅度误差、接收通道相位误差的产生原因;然后,推导了几类误差条件下的通用接收信号模型;最后,通过仿真实验说明了阵列误差会使定位算法的旁瓣电平升高。(3)提出了针对近场信号源的基于迭代优化的误差自校正算法。该算法对信号源位置与阵列误差进行联合估计,在估计误差参数的同时,将近场源参数的二维搜索问题转化为两个一维搜索问题,降低了算法的计算复杂度。此外,针对误差快/慢变化的系统中引起的高旁瓣问题,仿真实验表明了利用该二维校正算法能够对信号源位置与误差参数进行联合估计,从而有效抑制旁瓣。(4)将本文提到的旁瓣抑制技术运用到特定场景中进行了仿真实验与试验验证,分别进行了近场50米线阵两相干目标定位问题进行仿真模拟分析和5.8米稀疏线阵存在阵列误差情况下的实测数据验证分析。
[Abstract]:Because of the sparse arrangement of the array elements, the irregular sparse array increases the aperture of the antenna array, enhances its directivity, narrows the scanning beam, improves the spatial resolution obviously, and greatly weakens the mutual coupling effect between the array elements, while the irregularity enables the array to measure the angle without ambiguity. However, there are many factors in the actual array environment, such as mountains, rivers, swamps and so on. In the study of array configuration, it is also necessary to propose corresponding array arrangement methods for these geographical constraints. In addition, for the algorithm which estimates the direction of the source by processing the received signal of the sparse array, the direction finding performance is based on the accurate known premise of the array manifolds. However, in practical engineering applications, the real array manifolds tend to deviate to a certain extent with the change of many factors, which will increase the sidelobe level of the direction finding algorithm and even exceed the main lobe in serious cases. In this paper, an irregular array configuration method based on antenna size constraint and geographical environment constraint is studied for the array configuration problem of irregular sparse linear array with geographical constraints. At the same time, aiming at the problem of error affecting sidelobe in array antenna, the main work of array self-tuning method is as follows: (1) aiming at the problem of random sparse array configuration, the irregular sparse array signal model is given, and the optimization model of sparse array low sidelobe optimization is designed, and the unconstrained optimal array element allocation method based on pattern search is studied. Furthermore, aiming at the limitation of antenna size and geographical constraints in the actual array environment, the irregular array configuration method based on particle swarm optimization is studied. (2) aiming at the near-field narrowband signal modeling problem with array error in the actual scene, firstly, the causes of array position error, receiving channel amplitude error and receiving channel phase error are analyzed. Then, the general received signal models under several kinds of error conditions are derived. finally, the simulation results show that the array error will increase the sidelobe level of the positioning algorithm. (3) an error self-tuning algorithm based on iterative optimization for near-field signal sources is proposed. The algorithm estimates the position of the signal source and the array error jointly. While the error parameters are estimated, the two-dimensional search problem near the field source parameters is transformed into two one-dimensional search problems, which reduces the computational complexity of the algorithm. In addition, in order to solve the high sidelobe problem caused by fast / slow error change, the simulation results show that the two-dimensional correction algorithm can jointly estimate the position and error parameters of the signal source, thus effectively suppressing the sidelobe. (4) the sidelobe suppression technique mentioned in this paper is applied to a specific scene for simulation and experimental verification. The two-coherent target location problem of near-field 50m linear array is simulated and analyzed, and the measured data of 5.8m sparse linear array with array error are verified and analyzed respectively.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN911.7

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