In this paper, a novel direction of arrival(DOA) estimation algorithm using directional antennas in cylindrical conformal arrays(CCAs) is proposed. To eliminate the shadow effect, we divide the CCAs into several subar...In this paper, a novel direction of arrival(DOA) estimation algorithm using directional antennas in cylindrical conformal arrays(CCAs) is proposed. To eliminate the shadow effect, we divide the CCAs into several subarrays to obtain the complete output vector. Considering the anisotropic radiation pattern of a CCA, which cannot be separated from the manifold matrix, an improved interpolation method is investigated to transform the directional subarray into omnidirectional virtual nested arrays without non-orthogonal perturbation on the noise vector. Then, the cross-correlation matrix(CCM) of the subarrays is used to generate the consecutive co-arrays without redundant elements and eliminate the noise vector. Finally, the full-rank equivalent covariance matrix is constructed using the output of co-arrays,and the unitary estimation of the signal parameters via rotational invariance techniques(ESPRIT) is performed on the equivalent covariance matrix to estimate the DOAs with low computational complexity. Numerical simulations verify the superior performance of the proposed algorithm, especially under a low signal-to-noise ratio(SNR) environment.展开更多
The studies on clutter modeling and suppression of airborne radar with a parabolic conformal array are uncommon due to the complexity of this type of antenna array configuration.The correct understanding of clutter ch...The studies on clutter modeling and suppression of airborne radar with a parabolic conformal array are uncommon due to the complexity of this type of antenna array configuration.The correct understanding of clutter characteristics for airborne radar with a parabolic conformal antenna array is the prerequisite and foundation of optimal suppression of this type of clutter.This paper establishes the model of clutter echo of airborne parabolic conformal phased array radar and analyzes the structure characteristics and the distribution features of this type of clutter.The simulation results show that this type of clutter has the following characteristics：1） The main lobe on the azimuth is seriously broadened,2） the power spectrum presents strong heterogeneity,and 3） the freedom degrees are high.Based on the existing related clutter suppression methods,we verified the correctness of the constructed clutter model.This work has an important guidance to further study on clutter suppression methods in airborne parabolic conformal array radar.展开更多
利用分数阶傅里叶变换(fractional Fourier transform,FRFT)对线性调频(linear frequency modulation,LFM)信号的能量匹配聚焦特性来简化共形阵列的数据模型,根据子空间拟合原理提出一种信源DOA和极化参数的去耦联合估计方法.直接进行DO...利用分数阶傅里叶变换(fractional Fourier transform,FRFT)对线性调频(linear frequency modulation,LFM)信号的能量匹配聚焦特性来简化共形阵列的数据模型,根据子空间拟合原理提出一种信源DOA和极化参数的去耦联合估计方法.直接进行DOA估计涉及求解难度较大的多维多峰参数搜索过程,于是通过重构噪声子空间和流形矩阵建立了单峰的目标函数,然后用PSO算法估计信源方位角和俯仰角,在此基础上利用ESPRIT实现极化参数估计.仿真实验表明,去耦参数估计方法能在保证算法性能的前提下简化问题复杂度。展开更多
基金supported by the National Natural Science Foundation of China (NSFC) [grant number. 61871414]。
文摘In this paper, a novel direction of arrival(DOA) estimation algorithm using directional antennas in cylindrical conformal arrays(CCAs) is proposed. To eliminate the shadow effect, we divide the CCAs into several subarrays to obtain the complete output vector. Considering the anisotropic radiation pattern of a CCA, which cannot be separated from the manifold matrix, an improved interpolation method is investigated to transform the directional subarray into omnidirectional virtual nested arrays without non-orthogonal perturbation on the noise vector. Then, the cross-correlation matrix(CCM) of the subarrays is used to generate the consecutive co-arrays without redundant elements and eliminate the noise vector. Finally, the full-rank equivalent covariance matrix is constructed using the output of co-arrays,and the unitary estimation of the signal parameters via rotational invariance techniques(ESPRIT) is performed on the equivalent covariance matrix to estimate the DOAs with low computational complexity. Numerical simulations verify the superior performance of the proposed algorithm, especially under a low signal-to-noise ratio(SNR) environment.
基金supported by the Aeronautical Science Foundation of China under Grant No.20142080011
文摘The studies on clutter modeling and suppression of airborne radar with a parabolic conformal array are uncommon due to the complexity of this type of antenna array configuration.The correct understanding of clutter characteristics for airborne radar with a parabolic conformal antenna array is the prerequisite and foundation of optimal suppression of this type of clutter.This paper establishes the model of clutter echo of airborne parabolic conformal phased array radar and analyzes the structure characteristics and the distribution features of this type of clutter.The simulation results show that this type of clutter has the following characteristics：1） The main lobe on the azimuth is seriously broadened,2） the power spectrum presents strong heterogeneity,and 3） the freedom degrees are high.Based on the existing related clutter suppression methods,we verified the correctness of the constructed clutter model.This work has an important guidance to further study on clutter suppression methods in airborne parabolic conformal array radar.
文摘利用分数阶傅里叶变换(fractional Fourier transform,FRFT)对线性调频(linear frequency modulation,LFM)信号的能量匹配聚焦特性来简化共形阵列的数据模型,根据子空间拟合原理提出一种信源DOA和极化参数的去耦联合估计方法.直接进行DOA估计涉及求解难度较大的多维多峰参数搜索过程,于是通过重构噪声子空间和流形矩阵建立了单峰的目标函数,然后用PSO算法估计信源方位角和俯仰角,在此基础上利用ESPRIT实现极化参数估计.仿真实验表明,去耦参数估计方法能在保证算法性能的前提下简化问题复杂度。
