In this paper,a space-time adaptive processing(STAP)method is proposed for the airborne radar with the array amplitude-phase error considered,which is based on atomic norm minimization(ANM).In the conventional ANM-bas...In this paper,a space-time adaptive processing(STAP)method is proposed for the airborne radar with the array amplitude-phase error considered,which is based on atomic norm minimization(ANM).In the conventional ANM-based STAP method,the influence of the array amplitude-phase error is not considered and restrained,which inevitably causes performance deterioration.To solve this problem,the array amplitude-phase error is firstly estimated.Then,by pre-estimating the array amplitude-phase error information,a modified ANM model is built,in which the array amplitude-phase error factor is separated from the clutter response and the clutter covariance matrix(CCM)to improve the estimation accuracy of the CCM.To prove that the atomic norm theory is applicable in the presence of the array amplitude-phase error,the clutter sparsity is analyzed in this paper.Meanwhile,simulation results demonstrate that the proposed method is superior to the state-of-the-art STAP method.Moreover,the measured data is used to verify the effectiveness of the proposed method.展开更多
In this paper,we address the problem of multiple frequency-hopping(FH)signal parameters estimation in the presence of random missing observations.A space-time matrix with random missing observations is acquired by a u...In this paper,we address the problem of multiple frequency-hopping(FH)signal parameters estimation in the presence of random missing observations.A space-time matrix with random missing observations is acquired by a uniform linear array(ULA).We exploit the inherent incomplete data processing capability of atomic norm soft thresholding(AST)to analyze the space-time matrix and complete the accurate estimation of the hopping time and frequency of the received FH signals.The hopping time is obtained by the sudden changes of the spatial information,which is implemented as the boundary to divide the time domain signal so that each segment of the signal is a superposition of time-invariant multiple components.Then,the frequency of multiple signal components can be estimated precisely by AST within each segment.After obtaining the above two parameters of the hopping time and the frequency of signals,the direction of arrival(DOA)can be directly calculated by them,and the network sorting can be realized.Results of simulation show that the proposed method is superior to the existing technology.Even when a large portion of data observations is missing,as the number of array elements increases,the proposed method still achieves acceptable accuracy of multi-FH signal parameters estimation.展开更多
It is assumed that reconfigurable intelligent surface(RIS)is a key technology to enable the potential of mmWave communications.The passivity of the RIS makes channel estimation difficult because the channel can only b...It is assumed that reconfigurable intelligent surface(RIS)is a key technology to enable the potential of mmWave communications.The passivity of the RIS makes channel estimation difficult because the channel can only be measured at the transceiver and not at the RIS.In this paper,we propose a novel separate channel estimator via exploiting the cascaded sparsity in the continuously valued angular domain of the cascaded channel for the RIS-enabled millimeter-wave/Tera-Hz systems,i.e.,the two-stage estimation method where the cascaded channel is separated into the base station(BS)-RIS and the RIS-user(UE)ones.Specifically,we first reveal the cascaded sparsity,i.e.,the sparsity exists in the hybrid angular domains of BS-RIS and the RIS-UEs separated channels,to construct the specific sparsity structure for RIS enabled multi-user systems.Then,we formulate the channel estimation problem using atomic norm minimization(ANM)to enhance the proposed sparsity structure in the continuous angular domains,where a low-complexity channel estimator via Alternating Direction Method of Multipliers(ADMM)is proposed.Simulation findings demonstrate that the proposed channel estimator outperforms the current state-of-the-arts in terms of performance.展开更多
In this paper,we study the accuracy of delay-Doppler parameter estimation of targets in a passive radar using orthogonal frequency division multiplexing(OFDM)signal.A coarse-fine joint estimation method is proposed to...In this paper,we study the accuracy of delay-Doppler parameter estimation of targets in a passive radar using orthogonal frequency division multiplexing(OFDM)signal.A coarse-fine joint estimation method is proposed to achieve better estimation accuracy of target parameters without excessive computational burden.Firstly,the modulation symbol domain(MSD)method is used to roughly estimate the delay and Doppler of targets.Then,to obtain high-precision Doppler estimation,the atomic norm(AN)based on the multiple measurement vectors(MMV)model(MMV-AN)is used to manifest the signal sparsity in the continuous Doppler domain.At the same time,a reference signal compensation(RSC)method is presented to obtain highprecision delay estimation.Simulation results based on the OFDM signal show that the coarse-fine joint estimation method based on AN-RSC can obtain a more accurate estimation of target parameters compared with other algorithms.In addition,the proposed method also possesses computational advantages compared with the joint parameter estimation.展开更多
互耦效应是天线阵列工作时阵元相互之间产生的一种干扰影响,会导致理想导向矢量与真实导向矢量之间存在偏差,严重影响参数的估计性能。本文针对阵列互耦扰动下的波达方向(Di-rection of Arrival,DOA)估计问题,提出了一种新的原子范数最...互耦效应是天线阵列工作时阵元相互之间产生的一种干扰影响,会导致理想导向矢量与真实导向矢量之间存在偏差,严重影响参数的估计性能。本文针对阵列互耦扰动下的波达方向(Di-rection of Arrival,DOA)估计问题,提出了一种新的原子范数最小化方法MC-ANM,以提高参数估计精度。由于阵列互耦扰动下的原子结构不满足范德蒙德特性,原问题无法直接转化为半定规划程序。因此,文中基于对偶范数理论,推导了一个新的半定规划优化模型,作为原问题对应的对偶问题的充分近似,并构建了对偶多项式,以求解该半定规划优化中的DOA参数。仿真实验结果显示所提出的MC-ANM方法相较于传统原子范数最小化方法的估计性能有了明显的提升,同时估计精度要好于其他互耦扰动下的DOA估计算法。展开更多
为了提高极化敏感阵列中压缩感知类波达方向(Direction Of Arrival,DOA)估计算法的精度,避免网格失配问题,本文使用正交偶极子阵列在原子范数最小化(Atomic Norm Minimization,ANM)的理论基础上提出一种无网格波达方向估计算法.首先,将...为了提高极化敏感阵列中压缩感知类波达方向(Direction Of Arrival,DOA)估计算法的精度,避免网格失配问题,本文使用正交偶极子阵列在原子范数最小化(Atomic Norm Minimization,ANM)的理论基础上提出一种无网格波达方向估计算法.首先,将一维正交偶极子天线接收到的多快拍信号分解为两个子阵再求和,然后通过解决半正定规划问题恢复出一个含有入射信源信息的半正定Toeplitz矩阵,继而对该矩阵进行Vandermonde分解,恢复入射信源的DOA信息.同时结合协方差矩阵的向量化结果和最小二乘法计算得到入射信源的极化辅助角和极化相位角信息.通过仿真实验,在不同快拍数和信噪比下,对比子空间类算法和压缩感知类算法,证明了该算法具有较高的测角精度.展开更多
传统的基于原子范数最小化(Atomic Norm Minimization,ANM)的波达方向(Direction of Arrival,DOA)估计算法无法直接应用于不满足范德蒙德结构的非均匀圆阵,针对这一问题提出了一种基于虚拟阵列变换的改进方法。以某非均匀圆阵作原始阵...传统的基于原子范数最小化(Atomic Norm Minimization,ANM)的波达方向(Direction of Arrival,DOA)估计算法无法直接应用于不满足范德蒙德结构的非均匀圆阵,针对这一问题提出了一种基于虚拟阵列变换的改进方法。以某非均匀圆阵作原始阵列为例,首先通过虚拟阵列变换处理原始阵列接收的数据,使其转换为虚拟的均匀L阵接收数据,将非均匀圆阵上的DOA估计问题转化为两个均匀线阵上的DOA估计问题,再利用基于ANM的DOA估计算法与L型阵的二维角度关系还原出方位角和俯仰角。通过仿真与实测实验验证了所提算法应用于非均匀圆阵的可行性,并分析其DOA估计结果,证明其拥有较高的估计精度。展开更多
基金supported by the Fund for Foreign Scholars in University Research and Teaching Programs(the 111 Project)(B18039)。
文摘In this paper,a space-time adaptive processing(STAP)method is proposed for the airborne radar with the array amplitude-phase error considered,which is based on atomic norm minimization(ANM).In the conventional ANM-based STAP method,the influence of the array amplitude-phase error is not considered and restrained,which inevitably causes performance deterioration.To solve this problem,the array amplitude-phase error is firstly estimated.Then,by pre-estimating the array amplitude-phase error information,a modified ANM model is built,in which the array amplitude-phase error factor is separated from the clutter response and the clutter covariance matrix(CCM)to improve the estimation accuracy of the CCM.To prove that the atomic norm theory is applicable in the presence of the array amplitude-phase error,the clutter sparsity is analyzed in this paper.Meanwhile,simulation results demonstrate that the proposed method is superior to the state-of-the-art STAP method.Moreover,the measured data is used to verify the effectiveness of the proposed method.
文摘In this paper,we address the problem of multiple frequency-hopping(FH)signal parameters estimation in the presence of random missing observations.A space-time matrix with random missing observations is acquired by a uniform linear array(ULA).We exploit the inherent incomplete data processing capability of atomic norm soft thresholding(AST)to analyze the space-time matrix and complete the accurate estimation of the hopping time and frequency of the received FH signals.The hopping time is obtained by the sudden changes of the spatial information,which is implemented as the boundary to divide the time domain signal so that each segment of the signal is a superposition of time-invariant multiple components.Then,the frequency of multiple signal components can be estimated precisely by AST within each segment.After obtaining the above two parameters of the hopping time and the frequency of signals,the direction of arrival(DOA)can be directly calculated by them,and the network sorting can be realized.Results of simulation show that the proposed method is superior to the existing technology.Even when a large portion of data observations is missing,as the number of array elements increases,the proposed method still achieves acceptable accuracy of multi-FH signal parameters estimation.
文摘It is assumed that reconfigurable intelligent surface(RIS)is a key technology to enable the potential of mmWave communications.The passivity of the RIS makes channel estimation difficult because the channel can only be measured at the transceiver and not at the RIS.In this paper,we propose a novel separate channel estimator via exploiting the cascaded sparsity in the continuously valued angular domain of the cascaded channel for the RIS-enabled millimeter-wave/Tera-Hz systems,i.e.,the two-stage estimation method where the cascaded channel is separated into the base station(BS)-RIS and the RIS-user(UE)ones.Specifically,we first reveal the cascaded sparsity,i.e.,the sparsity exists in the hybrid angular domains of BS-RIS and the RIS-UEs separated channels,to construct the specific sparsity structure for RIS enabled multi-user systems.Then,we formulate the channel estimation problem using atomic norm minimization(ANM)to enhance the proposed sparsity structure in the continuous angular domains,where a low-complexity channel estimator via Alternating Direction Method of Multipliers(ADMM)is proposed.Simulation findings demonstrate that the proposed channel estimator outperforms the current state-of-the-arts in terms of performance.
基金supported by the National Natural Science Foundation of China(6193101562071335)+1 种基金the Technological Innovation Project of Hubei Province of China(2019AAA061)the Natural Science F oundation of Hubei Province of China(2021CFA002)。
文摘In this paper,we study the accuracy of delay-Doppler parameter estimation of targets in a passive radar using orthogonal frequency division multiplexing(OFDM)signal.A coarse-fine joint estimation method is proposed to achieve better estimation accuracy of target parameters without excessive computational burden.Firstly,the modulation symbol domain(MSD)method is used to roughly estimate the delay and Doppler of targets.Then,to obtain high-precision Doppler estimation,the atomic norm(AN)based on the multiple measurement vectors(MMV)model(MMV-AN)is used to manifest the signal sparsity in the continuous Doppler domain.At the same time,a reference signal compensation(RSC)method is presented to obtain highprecision delay estimation.Simulation results based on the OFDM signal show that the coarse-fine joint estimation method based on AN-RSC can obtain a more accurate estimation of target parameters compared with other algorithms.In addition,the proposed method also possesses computational advantages compared with the joint parameter estimation.
文摘互耦效应是天线阵列工作时阵元相互之间产生的一种干扰影响,会导致理想导向矢量与真实导向矢量之间存在偏差,严重影响参数的估计性能。本文针对阵列互耦扰动下的波达方向(Di-rection of Arrival,DOA)估计问题,提出了一种新的原子范数最小化方法MC-ANM,以提高参数估计精度。由于阵列互耦扰动下的原子结构不满足范德蒙德特性,原问题无法直接转化为半定规划程序。因此,文中基于对偶范数理论,推导了一个新的半定规划优化模型,作为原问题对应的对偶问题的充分近似,并构建了对偶多项式,以求解该半定规划优化中的DOA参数。仿真实验结果显示所提出的MC-ANM方法相较于传统原子范数最小化方法的估计性能有了明显的提升,同时估计精度要好于其他互耦扰动下的DOA估计算法。
文摘为了提高极化敏感阵列中压缩感知类波达方向(Direction Of Arrival,DOA)估计算法的精度,避免网格失配问题,本文使用正交偶极子阵列在原子范数最小化(Atomic Norm Minimization,ANM)的理论基础上提出一种无网格波达方向估计算法.首先,将一维正交偶极子天线接收到的多快拍信号分解为两个子阵再求和,然后通过解决半正定规划问题恢复出一个含有入射信源信息的半正定Toeplitz矩阵,继而对该矩阵进行Vandermonde分解,恢复入射信源的DOA信息.同时结合协方差矩阵的向量化结果和最小二乘法计算得到入射信源的极化辅助角和极化相位角信息.通过仿真实验,在不同快拍数和信噪比下,对比子空间类算法和压缩感知类算法,证明了该算法具有较高的测角精度.
文摘传统的基于原子范数最小化(Atomic Norm Minimization,ANM)的波达方向(Direction of Arrival,DOA)估计算法无法直接应用于不满足范德蒙德结构的非均匀圆阵,针对这一问题提出了一种基于虚拟阵列变换的改进方法。以某非均匀圆阵作原始阵列为例,首先通过虚拟阵列变换处理原始阵列接收的数据,使其转换为虚拟的均匀L阵接收数据,将非均匀圆阵上的DOA估计问题转化为两个均匀线阵上的DOA估计问题,再利用基于ANM的DOA估计算法与L型阵的二维角度关系还原出方位角和俯仰角。通过仿真与实测实验验证了所提算法应用于非均匀圆阵的可行性,并分析其DOA估计结果,证明其拥有较高的估计精度。