A new method for array calibration of array gain and phase uncertainties, which severely degrade the performance of spatial spectrum estimation, is presented. The method is based on the idea of the instrumental sensor...A new method for array calibration of array gain and phase uncertainties, which severely degrade the performance of spatial spectrum estimation, is presented. The method is based on the idea of the instrumental sensors method （ISM）, two well-calibrated sensors are added into the original array. By applying the principle of estimation of signal parameters via rotational invariance techniques （ESPRIT）, the direction-of-arrivals （DOAs） and uncertainties can be estimated simultaneously through eigen-decomposition. Compared with the conventional ones, this new method has less computational complexity while has higher estimation precision, what＇s more, it can overcome the problem of ambiguity. Both theoretical analysis and computer simulations show the effectiveness of the proposed method.展开更多
An aperture design technique using multi-step amplitude quantization for two-dimensional solid-state active phased arrays to achieve low sidelobe is described. It can be applied to antennas with arbitrary complex aper...An aperture design technique using multi-step amplitude quantization for two-dimensional solid-state active phased arrays to achieve low sidelobe is described. It can be applied to antennas with arbitrary complex aperture. Also, the gain drop and sidelobe degradation due to random amplitude and phase errors and element (or T/R module) failures are investigated.展开更多
The effect of gain-phase perturbations and mutual coupling significantly degrades the performance of digital array radar (DAR). This paper investigates array calibration problems in the scenario where the true locatio...The effect of gain-phase perturbations and mutual coupling significantly degrades the performance of digital array radar (DAR). This paper investigates array calibration problems in the scenario where the true locations of auxiliary sources deviate from nominal values but the angle intervals are known. A practical algorithm is proposed to jointly calibrate gain-phase errors and mutual coupling errors. Firstly, a simplified model of the distortion matrix is developed based on its special structure in uniform linear array (ULA). Then the model is employed to derive the precise locations of the auxiliary sources by one-dimension search. Finally, the least-squares estimation of the distortion matrix is obtained. The algorithm has the potential of achieving considerable improvement in calibration accuracy due to the reduction of unknown parameters. In addition, the algorithm is feasible for practical applications, since it requires only one auxiliary source with the help of rotation platforms. Simulation results demonstrate the validity, robustness and high performance of the proposed algorithm. Experiments were carried out using an S-band DAR test-bed. The results of measured data show that the proposed algorithm is practical and effective in application. (C) 2016 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.展开更多
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 assu...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 all these array perturbations. The ISM can be applied to arbitrary array geometries including linear arrays. The ISM is computationally efficient and requires only one-dimensional search, with no high-dimensional nonlinear search and convergence burden involved. Besides, no small error assumption is made, which is always an essential prerequisite for many existing array calibration techniques. The estimation performance of the ISM is analyzed theoretically and simulation results are provided to demonstrate the effectiveness and behavior of the proposed ISM.展开更多
Optical phased arrays(OPAs)have broad application prospects due to their advanced capability in beamforming and steering.In this work,we achieve independent dual beams in the far field by dividing the array elements o...Optical phased arrays(OPAs)have broad application prospects due to their advanced capability in beamforming and steering.In this work,we achieve independent dual beams in the far field by dividing the array elements of the OPA,with the maximum scanning range reaching 100°.Based on the working principle of OPAs,theoretical considerations of such multibeam generation are presented.A phase data allocation approach for OPAs in the presence of fabrication-induced random phase variation is developed.Simulations of large ensembles of OPAs with various levels of random residual phase errors have been conducted to help analyze the results.This approach can help OPAs realize multi-beams for light detection and ranging(LiDAR).展开更多
针对多径环境中均匀线阵(uniform linear array,ULA)的幅相误差的校正问题,在不破坏阵列幅相误差矩阵的前提下,提出了一种多径条件下基于辅助阵元的波达方向(direction of arrival,DOA)估计及幅相误差自校正算法。利用阵列平移的方法对...针对多径环境中均匀线阵(uniform linear array,ULA)的幅相误差的校正问题,在不破坏阵列幅相误差矩阵的前提下,提出了一种多径条件下基于辅助阵元的波达方向(direction of arrival,DOA)估计及幅相误差自校正算法。利用阵列平移的方法对相干信号进行解相干预处理,再利用辅助阵元依据子空间原理构建代阶函数实现相干信源的方位估计,进而对阵列幅相误差进行估计。计算机仿真结果表明,该算法对多径环境下的相干信源具有准确的方位估计与幅相误差自校正性能。展开更多
文摘A new method for array calibration of array gain and phase uncertainties, which severely degrade the performance of spatial spectrum estimation, is presented. The method is based on the idea of the instrumental sensors method （ISM）, two well-calibrated sensors are added into the original array. By applying the principle of estimation of signal parameters via rotational invariance techniques （ESPRIT）, the direction-of-arrivals （DOAs） and uncertainties can be estimated simultaneously through eigen-decomposition. Compared with the conventional ones, this new method has less computational complexity while has higher estimation precision, what＇s more, it can overcome the problem of ambiguity. Both theoretical analysis and computer simulations show the effectiveness of the proposed method.
文摘An aperture design technique using multi-step amplitude quantization for two-dimensional solid-state active phased arrays to achieve low sidelobe is described. It can be applied to antennas with arbitrary complex aperture. Also, the gain drop and sidelobe degradation due to random amplitude and phase errors and element (or T/R module) failures are investigated.
基金supported by the National Natural Science Foundation of China (No. 61571449)
文摘The effect of gain-phase perturbations and mutual coupling significantly degrades the performance of digital array radar (DAR). This paper investigates array calibration problems in the scenario where the true locations of auxiliary sources deviate from nominal values but the angle intervals are known. A practical algorithm is proposed to jointly calibrate gain-phase errors and mutual coupling errors. Firstly, a simplified model of the distortion matrix is developed based on its special structure in uniform linear array (ULA). Then the model is employed to derive the precise locations of the auxiliary sources by one-dimension search. Finally, the least-squares estimation of the distortion matrix is obtained. The algorithm has the potential of achieving considerable improvement in calibration accuracy due to the reduction of unknown parameters. In addition, the algorithm is feasible for practical applications, since it requires only one auxiliary source with the help of rotation platforms. Simulation results demonstrate the validity, robustness and high performance of the proposed algorithm. Experiments were carried out using an S-band DAR test-bed. The results of measured data show that the proposed algorithm is practical and effective in application. (C) 2016 Production and hosting by Elsevier Ltd. on behalf of Chinese Society of Aeronautics and Astronautics.
文摘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 all these array perturbations. The ISM can be applied to arbitrary array geometries including linear arrays. The ISM is computationally efficient and requires only one-dimensional search, with no high-dimensional nonlinear search and convergence burden involved. Besides, no small error assumption is made, which is always an essential prerequisite for many existing array calibration techniques. The estimation performance of the ISM is analyzed theoretically and simulation results are provided to demonstrate the effectiveness and behavior of the proposed ISM.
基金supported by the National Natural Science Foundation of China(Nos.62175103 and 62165015)the National Key Research and Development Program of China(No.2017YFA0303700).
文摘Optical phased arrays(OPAs)have broad application prospects due to their advanced capability in beamforming and steering.In this work,we achieve independent dual beams in the far field by dividing the array elements of the OPA,with the maximum scanning range reaching 100°.Based on the working principle of OPAs,theoretical considerations of such multibeam generation are presented.A phase data allocation approach for OPAs in the presence of fabrication-induced random phase variation is developed.Simulations of large ensembles of OPAs with various levels of random residual phase errors have been conducted to help analyze the results.This approach can help OPAs realize multi-beams for light detection and ranging(LiDAR).
文摘针对多径环境中均匀线阵(uniform linear array,ULA)的幅相误差的校正问题,在不破坏阵列幅相误差矩阵的前提下,提出了一种多径条件下基于辅助阵元的波达方向(direction of arrival,DOA)估计及幅相误差自校正算法。利用阵列平移的方法对相干信号进行解相干预处理,再利用辅助阵元依据子空间原理构建代阶函数实现相干信源的方位估计,进而对阵列幅相误差进行估计。计算机仿真结果表明,该算法对多径环境下的相干信源具有准确的方位估计与幅相误差自校正性能。
