Array errors active calibration algorithm based on instrumental sensors

The array mutual coupling,gain-phase errors and sensor position errors would significantly degrade the performance of high-resolution direction of arrival (DOA) estimation algorithms.Aiming at the combined influences of the above three array errors,a kind of active calibration algorithm is presented with the help of instrumental sensors in this paper.Firstly,the integrated effects of the three array errors are shown to be equivalent to angularly dependent gain-phase errors.Then,a non-linear least square (LS...     

基于辅助阵元的阵列误差有源校正算法

阵列互耦、幅相误差和阵元位置误差的综合影响会严重影响超分辨率算法的性能,为此,针对上述3种阵列误差的综合影响,给出了一类基于辅助阵元的有源校正算法.首先,将3种阵列误差的综合影响等效为一种依赖方位变化的幅相误差,并通过一种基于辅助阵元的自校正方法得到了关于3种阵列误差的非线性最小二乘优化模型;然后,针对阵列误差矩阵可能出现的不同模型,给出了相应的求解算法;接着,针对算法的参数估计唯一性给出了较为细致的分析,并对算法做了进一步改进;最后,通过仿真实验验证了新算法的有效性.     

机会式电磁矢量传感器阵列互耦校正算法

针对电磁矢量传感器阵列中的互耦效应导致系统性能下降的问题,研究了一种分布式电磁矢量传感器机会式阵列互耦校正算法。首先建立可以从信噪比、波达方向估计精度和孔径扩展维数等性能方面分析线性阵列、三角形阵列和双三角形阵列等阵列结构特性的数学模型,然后根据性能分析结果构建了电磁矢量传感器机会式阵列架构,最后提出了适用于分布式电磁矢量传感器阵列的机会式互耦校正算法。实验结果从波达方向估计精度、空间谱估计精度和信噪比等方面证明了所提分布式电磁矢量传感器机会式阵列互耦校正算法比静态传感器阵列具有明显优势。     

一种经典阵元幅相误差、阵元间互耦自校正方法的仿真分析

阵元幅相误差以及阵元间互耦的存在会使大多数高分辨DOA估计算法的性能恶化或失效。因此,阵列误差的校正技术在实际工程应用中具有重要的意义。本文基于一种经典自校正算法进行仿真分析,针对较多文章在理论上分析说明此方法对于均匀线阵的局限性,本文主要考查在实际应用中,在一定条件下此方法同样适用于均匀线阵。     

A self-calibration algorithm for cross array in the presence of mutual coupling

In this paper,a novel blind mutual coupling self-calibration algorithm especially tailored to cross array is proposed.This method compensates for the mutual coupling not only between sensors in each subarray but also between two subarrays.Exploiting the property of coupling matrix,the proposed method requires neither the calibration sources in known locations nor the multidimensional nonlinear search.This method can jointly estimate the DOAs of the incoming signals and the unknown mutual coupling coefficien...     

Robust DOA estimation and array calibration in the presence of mutual coupling for uniform linear array

The presence of unknown mutual coupling between array elements is knownto significantly degrade the performance of most high-resolution direction of arrival (DOA)estimation algorithms. In this paper, a robust subspace-based DOA estimation and arrayauto-calibration algorithm is proposed for uniformly linear array (ULA), when the arraymutual coupling is present. Based on a banded symmetric Toeplitz matrix model for themutual coupling of ULA, the algorithm provides an accurate and high-resolution DOAestimate without any knowledge of the array mutual couplings. Moreover, a favorableestimate of mutual coupling matrix can also be achieved simultaneously for arrayauto-calibration. The algorithm is realized just via one-dimensional search or polynomialrooting, with no multidimensional nonlinear search or convergence burden involved. Theproblem of parameter ambiguity, statistically consistence and efficiency of the newestimator are also analyzed. Monte-Carlo simulation results are also provided todemonstrate the     

基于均匀圆阵的互耦误差校正算法研究

阵元之间的互耦效应严重影响了DOA的估计性能。基于均匀圆阵,提出了一种互耦条件下的波达方向估计和互耦误差自校正算法。利用带状循环矩阵的特性对均匀圆阵的互耦误差建立数学模型,再利用MUSIC算法和迭代法对互耦误差矩阵和波达方向同时进行估计,自校正方法无需任何辅助阵元即可实现两类参数的估计。仿真实验表明,算法很好地解决了均匀圆阵的互耦问题,能够比较准确地估计出波达方向角和互耦误差值。     

Array calibration of angularly dependent gain and phase uncertainties with carry-on instrumental sensors

Array calibration with angularly dependent gain and phase uncertainties has long been a difficult problem. Although many array calibration methods have been reported extensively in the literature, they almost all assumed an angularly independent model for array uncertainties. Few calibration methods have been developed for the angularly dependent array uncertainties. A novel and efficient auto-calibration method for angularly dependent gain and phase uncertainties is proposed in this paper, which is called ISM (Instrumental Sensors Method). With the help of a few well-calibrated instrumental sensors, the ISM is able to achieve favorable and unambiguous direction-of-arrivals (DOAs) estimate and the corresponding angularly dependent gain and phase estimate simultaneously, even in the case of multiple non-disjoint sources. Since the mutual coupling and sensor position errors can all be described as angularly dependent gain/phase uncertainties, the ISM proposed still works in the presence of a combination of     

Joint direction of arrival estimation and array calibration for coprime MIMO radar

Compared to large-scale MIMO radar, coprime MIMO radar can achieve approximate estimation performance with reduced antenna number. In this paper, joint direction of arrival (DOA) estimation and array calibration for coprime multiple-input multiple-output (MIMO) radar is considered, and an iterative method for the estimations of DOA and array gain-phase errors is proposed. Based on the received data structure of coprime MIMO radar, trilinear decomposition is firstly adopted to obtain the estimations of transmit and receive direction matrices, which are perturbated by the gain-phase errors. Through equation transformation, the un-perturbated direction matrices and gain-phase errors can be iteratively updated based on Least squares (LS). Finally, the unique DOA estimation is determined from the intersection of transmit and receive direction matrices. The proposed algorithm achieves better DOA estimation and array calibration performance than other methods including estimation of signal parameters via rotational invariance techniques (ESPRIT)-like algorithm, multiple signal classification (MUSIC)-like algorithm and joint angle and array gain-phase error estimation (JAAGE) method, and it performs close to the method with ideal arrays. Multiple simulation results verify the algorithmic effectiveness of the proposed method.     

基于IMU阵列的标定方法

微电子机械系统(MEMS)技术的发展使惯性传感器行业发生了革命性的变化,这使得生产惯性传感器阵列成为可能。然而,低成本的惯性测量系统会受到比例因子和轴失准误差的影响,从而造成位置和姿态估计的精度降低。在单个IMU校正的基础上,设计了一套基于IMU阵列的标定方法,该标定方法为了解决传统六面法在标定IMU阵列过程中方向激励不足的问题,设计了正20面的校正装置,该标定方法不仅能够估计出IMU阵列中单个IMU的比例因子、轴失准误差和偏置,还能估计出阵列中不同IMU之间的坐标轴对齐误差。通过把标定结果和官方所给的校正参数进行对比,可以得到经过本文所提的IMU阵列标定方法得到的标定结果能够达到工厂标定结果的百分之五十到百分之九十。     

Modeling of mutual coupling of arbitrary order in coupled circuits and array antennas

This article presents a fundamental strategy for accurately modeling the mutual coupling of arbitrary order in any large‐scale electromagnetic structures and high‐density integrated chips such as antenna array elements and coupled circuit elements. The proposed method starts from the modeling of the first‐order mutual coupling, and it consists of two main steps. First of all, an equivalent circuit model describing low‐order mutual coupling (adjacent coupling) is characterized and established, of which each parametric value is accurately extracted by making use of a numerical calibration technique. Then, the circuit model for high‐order mutual coupling (crossover or crosstalk coupling) is generated from the lower order models, and it can further be used for the modeling of mutual coupling of any higher order. The accuracy and efficiency of the proposed method are demonstrated by three different kinds of structure including a linear phased array antenna, a finite periodic electromagnetic structure, and a planar low‐pass filter. This novel approach represents an easy, fast, and effective characterization of arbitrary‐order mutual coupling. It can find applications in the modeling of mutual coupling between any circuit elements and building blocks such as antennas, resonators, and even small discontinuities, and it promises to be helpful for the analysis and iterative design of microwave circuits and antenna arrays. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

基于面阵的多目标角度跟踪算法

为了实现移动目标的自动角度跟踪,提出了一种基于面阵的多目标角度跟踪算法.通过估计相邻时间段的协方差矩阵,求解方程组得到目标角度更新信息;同时引入了校正过程,降低了累积误差,提高了跟踪精度.该算法不需要更新信号子空间,相邻时段估计的角度是自动关联的,省去了数据关联过程,降低了运算量;不同于一维角度跟踪算法,该算法可以同时跟踪移动目标的方位角和俯仰角.仿真结果表明了该算法的有效性.     

L型阵列通道不一致及阵元位置误差的联合校正方法

针对L型阵列中通道不一致和阵元位置误差同时存在的情况,利用辅助阵列和校正源,提出一种L型阵列通道不一致和阵元位置误差的解耦合估计方法.该方法计算量小,不需要误差参数的任何先验知识,且校正源的位置可以未知.理论分析和仿真结果表明,提出的方法能很好地解决L型阵列中通道不一致和阵元位置误差的联合校正问题,且两种误差的估计精度高.     

Adaptive nulling of a linear dipole array in the presence of mutual coupling

This article proposes a novel mutual impedance matrix model for compensating mutual coupling effects in adaptive array with application to adaptive nulling of interference signals. In the new method, extreme care has been taken into account for both self impedance and mutual impedance, relating to the mutual coupling effects. Numerical simulation results demonstrate the robustness and capability of this technique. By using the new method, it is found that both the accuracy of the positioning and depth of the nulls are significantly improved. Performance comparisons of the new methodology and several other previous techniques via a number of simulation are presented. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:30–38, 2014.     

Design of microstrip line-fed patch arrays including mutual coupling

A computer-aided design algorithm is developed to facilitate the design of E-plane series-fed patch arrays. A rigorous moment method is used to compute the impedance of and the currents on each patch element in the array. Mutual coupling between adjacent patch elements is included in the computation. Experimental validation of the algorithm is reported. The effects of fabrication tolerance, material parameter variations, and mutual coupling on the array performance are highlighted.     

Direct position determination in the presence of model errors—known waveforms

The performance of the direct position determination (DPD) approach in the presence of model errors is examined. DPD was recently introduced as a promising technique for localization of multiple radio frequency emitters with superior accuracy under low signal-to-noise ratio conditions. We analyze the performance of DPD in the presence of model errors caused by multipath, calibration errors, mutual coupling, etc. The analysis is general enough to encapsulate various sources of errors. Monte Carlo simulations are used to validate the analysis. We show that in many cases of interest DPD should be selected as the preferred method of localization.     

基于子空间类法的阵列幅相误差校正方法

该文针对阵列误差条件下多目标方位高分辨估计问题,提出了一种基于子空间类法的阵列幅相误差校正方法,实现过程简单,效果显著。计算机仿真结果表明,该校正方法可以有效地改善子空间类方法的稳健性,提高其多目标分辨能力,而且方位参数估计精度良好,具有较好的工程应用前景。     

Performance of a circular crossed‐dipole array for SDMA configuration adopting directivity and polarization control using particle swarm optimization algorithm

In this article, the performance of a circular crossed‐dipole array (CCDA) for space division multiple access (SDMA) configurations adopting directivity and polarization control is presented. The array consists of 12 dual‐polarized elements uniformly distributed in a circular configuration; each dual‐polarized element (crossed‐dipole) consists of two half‐wave dipoles in a ±45° slant configuration. The modified particle swarm optimization and moment of method (MPSO‐MOM) algorithm is used to calculate the complex weightings of the array elements in a mutual coupling environment for beamforming synthesis. In addition, the performance of the adaptive array using discrete feedings (1‐bit amplitude and 4‐bit phase shifters or only 4‐bit phase shifters) is studied. © 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

Compact U‐array MIMO antenna designs using IWO algorithm

In this article, design of a novel compact four‐channel multiple input multiple output (MIMO) antenna is described. The antenna is composed of four U‐shaped patch elements and operates at 5.8 GHz. The single U‐shaped patch antenna, to operate at this frequency, is designed using the Invasive Weed optimization algorithm. This algorithm is then applied to design two and four‐channel MIMO antenna arrays for high degree of isolation. To measure the array performance under MIMO signaling conditions, a multiport metric is used to characterize the compact array rather than the scattering matrix characterization. The measurement and simulation results of reflection coefficient, mutual coupling, and radiation pattern are presented and discussed. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.     

Localization of mixed far-field and near-field sources under unknown mutual coupling

In this paper, a novel localization algorithm for mixed far-field and near-field sources is proposed in the presence of unknown mutual coupling. Based on the principle of rank reduction, direction-of-arrival (DOA) estimates of far-field sources are firstly decoupled under unknown mutual coupling. Then these estimates are employed to generate the mutual coupling coefficients. Finally, by the mutual coupling compensation and the far-field components elimination, near-field sources parameters (DOA and range) are obtained. The proposed algorithm is efficient in that it only requires second order statistics and one dimensional spectral search. Simulation results demonstrate that our algorithm is effective for the classification and localization of mixed sources under unknown mutual coupling.