Most of the direction of arrival(DOA) estimation methods often need the exact array manifold, but in actual applications,the gain and phase of the channels are usually inconsistent, which will cause the estimation inv...Most of the direction of arrival(DOA) estimation methods often need the exact array manifold, but in actual applications,the gain and phase of the channels are usually inconsistent, which will cause the estimation invalid. A novel direction finding approach for mixed far-field and near-field signals with gain-phase error array is provided. Based on simplifying the space spectrum function by matrix transformation, DOA of far-field signals is obtained. Consequently, errors of the array are acquired according to the orthogonality of far-field signal subspace and noise subspace.Finally, DOA of near-field signals can be estimated. The method merely needs one-dimensional spectrum searching, so as to improve the computational efficiency on the premise of ensuring a certain accuracy, simulation results manifest the effectiveness of the method.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
接收设备各通道间相位不一致会导致接收及构造信号失真,采用通道均衡技术可解决上述问题,但会产生额外的计算资源开销。以构造信号脉压增益损失模型为基础,研究了通道间相位失配的影响机理,并系统量化分析了采用通道校正的必要性。首先...接收设备各通道间相位不一致会导致接收及构造信号失真,采用通道均衡技术可解决上述问题,但会产生额外的计算资源开销。以构造信号脉压增益损失模型为基础,研究了通道间相位失配的影响机理,并系统量化分析了采用通道校正的必要性。首先,基于线性调频(Linear Frequency Modulated,LFM)信号的时频特性,建立了多通道信号分析模型。然后,分别以双通道和三通道信号为例,系统解析了相位误差分布、信号截断位置与脉压增益损失的定量关系。最后,通过仿真实验验证了理论分析的正确性,为量化评估通道均衡的必要性提供了参考依据。展开更多
提出一种基于人工磁导体(Artificial Magnetic Conductor, AMC)的高增益宽带天线,该天线由一个AMC超表面和一个微带贴片天线组成。利用AMC的同相反射特性,将天线的后向辐射反射与前向辐射叠加,从而提升了天线的增益。天线的整体尺寸为0....提出一种基于人工磁导体(Artificial Magnetic Conductor, AMC)的高增益宽带天线,该天线由一个AMC超表面和一个微带贴片天线组成。利用AMC的同相反射特性,将天线的后向辐射反射与前向辐射叠加,从而提升了天线的增益。天线的整体尺寸为0.6λ_(0)×0.6λ_(0)×0.12λ_(0) (λ_(0)为天线谐振频率对应的波长)。测试结果表明,在4.55~6.1 GHz (27.7%)的工作频段内,天线的峰值增益达到8.4 dB。与利用理想电导体(Perfect Electric Conductor, PEC)提升增益的方法相比,其剖面从0.37λ_(0)降低到0.12λ_(0)。该天线剖面低、尺寸小、增益高、成本低廉,可以应用于WLAN波段通信。展开更多
文章旨在减轻Time of Flight(ToF)相机在动态场景中产生的运动模糊,以提升图像质量和深度信息的准确性。提出了一种基于增益标定的矫正方法,通过增益标定精确测定每个像素的增益系数,并引入深度解算原理中的四位相移法以此优化曝光时间...文章旨在减轻Time of Flight(ToF)相机在动态场景中产生的运动模糊,以提升图像质量和深度信息的准确性。提出了一种基于增益标定的矫正方法,通过增益标定精确测定每个像素的增益系数,并引入深度解算原理中的四位相移法以此优化曝光时间,从而达到提升图像质量和深度测量精度的效果。在运动模糊测试平台上对改善效果进行一系列测试。结果表明,该方法能显著提高ToF相机在动态场景下的深度图像质量,在测试装置转速为100~200 r/min内时,由运动模糊产生的错误像素数减少百分比可达35%以上,最高可达41.46%。通过实验验证,基于增益标定的ToF相机运动模糊矫正方法能有效提升图像质量和深度信息的准确性,展现了其在动态环境下的广泛应用潜力。展开更多
基金supported by the National Natural Science Foundation of China(6150117661505050)+5 种基金the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(UNPYSCT-2016017)the Natural Science Foundation of Heilongjiang Province(F2015015)the Outstanding Young Scientist Foundation of Heilongjiang University(JCL201504)the China Postdoctoral Science Foundation(2014M561381)the Postdoctoral Foundation of Heilongjiang Province(LBH-Z14178)the Special Research Funds for the Universities of Heilongjiang Province(HDRCCX-2016Z10)
文摘Most of the direction of arrival(DOA) estimation methods often need the exact array manifold, but in actual applications,the gain and phase of the channels are usually inconsistent, which will cause the estimation invalid. A novel direction finding approach for mixed far-field and near-field signals with gain-phase error array is provided. Based on simplifying the space spectrum function by matrix transformation, DOA of far-field signals is obtained. Consequently, errors of the array are acquired according to the orthogonality of far-field signal subspace and noise subspace.Finally, DOA of near-field signals can be estimated. The method merely needs one-dimensional spectrum searching, so as to improve the computational efficiency on the premise of ensuring a certain accuracy, simulation results manifest the effectiveness of the method.
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.
文摘接收设备各通道间相位不一致会导致接收及构造信号失真,采用通道均衡技术可解决上述问题,但会产生额外的计算资源开销。以构造信号脉压增益损失模型为基础,研究了通道间相位失配的影响机理,并系统量化分析了采用通道校正的必要性。首先,基于线性调频(Linear Frequency Modulated,LFM)信号的时频特性,建立了多通道信号分析模型。然后,分别以双通道和三通道信号为例,系统解析了相位误差分布、信号截断位置与脉压增益损失的定量关系。最后,通过仿真实验验证了理论分析的正确性,为量化评估通道均衡的必要性提供了参考依据。
文摘文章旨在减轻Time of Flight(ToF)相机在动态场景中产生的运动模糊,以提升图像质量和深度信息的准确性。提出了一种基于增益标定的矫正方法,通过增益标定精确测定每个像素的增益系数,并引入深度解算原理中的四位相移法以此优化曝光时间,从而达到提升图像质量和深度测量精度的效果。在运动模糊测试平台上对改善效果进行一系列测试。结果表明,该方法能显著提高ToF相机在动态场景下的深度图像质量,在测试装置转速为100~200 r/min内时,由运动模糊产生的错误像素数减少百分比可达35%以上,最高可达41.46%。通过实验验证,基于增益标定的ToF相机运动模糊矫正方法能有效提升图像质量和深度信息的准确性,展现了其在动态环境下的广泛应用潜力。
