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High sidelobe effects on interferometric coherence for circular SAR imaging geometry

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Journal of Systems Engineering and Electronics 2013年第1期24卷 76-83页

作者： Leilei Kou Xiaoqing Wang maosheng xiang Minhui Zhu School of Atmospheric Physics Nanjing University of Information Science and Technology Institute of Electronics Chinese Academy of Sciences

The coherence is a measure for the accuracy of the interferometric phase, and the synthetic aperture radar （SAR） inter- ferometric coherence is affected by several sources of the decor- relation noise. For the circular SAR （CSAR） imaging geometry, the system response function is in the form of the Bessel function which brings a high sidelobe, and the high sidelobe of CSAR will be an important factor influencing the interferometric coherence. The effect of the high sidelobe on the coherence is analyzed and deduced. Based on the interferometric characteristics of the slight difference in the viewing angles and the potential pixel off- set in the interferometric SAR （InSAR） images, a relation between the radar impulse response and the coherence loss function is derived. From the relational model, the coherence loss function due to the high sidelobe of CSAR is then deduced, and compared with that of the conventional SAR. It is shown that the high sidelobe of CSAR focusing signal will severely affect the baseline decorre- lation and coregistration decorrelation. Simulation results confirm the theoretical analysis and quantitatively show the baseline and coregistration decorrelation degradation due to the high sidelobes of CSAR.

关键词： interferometric coherence circular SAR (CSAR) high sidelobe interferometric SAR (InSAR) baseline decorrelation coregistration decorrelation.

Circular SAR processing using an improved omega-k type algorithm

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Journal of Systems Engineering and Electronics 2010年第4期21卷 572-579页

作者： Leilei KOU Xiaoqing Wang Jinsong Chong maosheng xiang Minhui Zhu National Key Laboratory of Microwave Imaging Technology Institute of Electronics Chinese Academy of Sciences Beijing 100190 P. R. China Graduate University of Chinese Academy of Sciences Beijing 100049 P. R. China

An improved circular synthetic aperture radar（CSAR） imaging algorithm of omega-k（ω-k） type mainly for reconstructing an image on a cylindrical surface is *** the typical CSAR ω-k algorithm,the rage trajectory is approximated by Taylor series expansion to the quadratic terms,which limits the valid synthetic aperture length and the angular reconstruction range *** on the model of the CSAR echo signal,the proposed algorithm directly transforms the signal to the two-dimensional（2D） wavenumber domain,not using approximation processing to the range *** on form of the signal spectrum in the wavenumber domain,the formula for the wavenumber domain interpolation of the w-k algorithm is deduced,and the wavenumber spectrum of the reference point used for bulk compression is obtained from numerical *** improved CSAR ω-k imaging algorithm increases the valid synthetic aperture length and the angular area greatly and hence improves the angular resolution of the cylindrical ***,the proposed algorithm can be repeated on different cylindrical surfaces to achieve three dimensional（3D） image *** 3D spatial resolution of the CSAR system is discussed,and the simulation results validate the correctness of the analysis and the feasibility of the algorithm.

关键词： circular synthetic aperture radar omega-k algorithm wavenumber domain three-dimensional spatial resolution.

RESEARCH ON PERFORMANCE INFLUENCE OF DIRECT-PATH SIGNAL FOR DVB-S BASED PASSIVE RADAR

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Journal of Electronics(China) 2013年第2期30卷 111-117页

作者： Jin Wei Lü Xiaode xiang maosheng National Key Laboratory of Science and Technology on Microwave Imaging Institute of ElectronicsChinese Academy of Sciences University of Chinese Academy of Sciences

Passive radar detects moving targets by Cross Ambiguity Function (CAF), which is based on the cross correlation process of the direct-path signal in reference channel and echo signal in receive channel. Thus, the performance of direct-path signal is important to system performance for this type of radar. While the Signal to Noise Ratio (SNR) of direct-path signal is low, it will deteriorate the detection performance. In this paper, how SNR of direct-path signal induces degradation on the SNR of CAF, and how the integration gain affects by integration time are analyzed, both with theoretical analysis and numerical simulation, which are valuable for the R&D of passive radar.

关键词： Passive radar Cross Ambiguity Function (CAF) Signal to Noise Ratio (SNR) loss Range walk Doppler walk

CHANNEL ERROR CORRECTION FOR WIDEBAND SAR-A JOINT MULTIPLE SUBPULSES PROCESSING METHOD

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Journal of Electronics(China) 2011年第1期28卷 134-140页

作者： Chen Shuxuan Jiang Limin xiang maosheng National Key Lab of Microwave Imaging Technology Institute of Electronics Chinese Academy of Sciences Beijing 100190 China Graduate School of Chinese Academy of Sciences Beijing 100190 China

A novel method,referred to as joint multiple subpulses processing,is developed to calibrate the nonideal transfer function of radio frequency front-end and I/Q imbalance in quadrature modulate/demodulate systems simultaneously,which frequently occur in wideband Synthetic Aperture Radar(SAR) *** on the time-frequency relation of the chirp signal and the analyses of the channel errors in wideband SAR,joint multiple subpulses processing method is adopted to separate the image frequency component due to the I/Q channel ***,the complete description of the channel error is acquired for building the correction function,which is used to correct the radar raw echo in frequency *** validity and capability of this method are demonstrated by the experiments of the channel error correction on the high resolution SAR system with the effective bandwidth of 500 MHz.

关键词： Wideband Synthetic Aperture Radar(SAR) Channel error Joint multiple subpulses processing Weighted least squares Correction function

大气折射率时间变化对地球同步轨道圆迹SAR聚焦性能的影响

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测绘学报 2014年第9期43卷 917-923页

作者：寇蕾蕾向茂生南京信息工程大学大气物理学院江苏南京210044 中国科学院电子学研究所北京100190

根据地球同步轨道圆迹SAR(GEOCSAR)的特点,大气折射率时间变化将会对GEOCSAR方位向聚焦成像产生重要影响。本文考虑L波段GEOCSAR的特点,因此对流层和电离层效应均不可忽略。文中建立了对流层和电离层折射率时间变化引起的相位误差模型,... 详细信息

根据地球同步轨道圆迹SAR(GEOCSAR)的特点,大气折射率时间变化将会对GEOCSAR方位向聚焦成像产生重要影响。本文考虑L波段GEOCSAR的特点,因此对流层和电离层效应均不可忽略。文中建立了对流层和电离层折射率时间变化引起的相位误差模型,分析和推导了折射率时间变化对GEOCSAR方位向聚焦性能的影响,计算了引起L波段GEOCSAR聚焦性能退化的最小对流层折射率和电离层电子含量随机时间变化量,并通过仿真进行了验证。

关键词：地球同步轨道圆迹SAR 大气折射率时间变化对流层电离层

THE EFFECT OF IMU INACCURACIES ON AIRBORNE SAR IMAGING

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Journal of Electronics(China) 2011年第4期28卷 409-418页

作者： Mao Yongfei xiang maosheng Wei Lideng Han Songtao National Key Laboratory of Science and Technology on Microwave Imaging Institute of Electronics Chinese Academy of Sciences. Beijing 100190 China Graduate University of Chinese Academy of Sciences Beijing 100039 China Beijing Aerospace Control Center Beijing 1000P4 China

When using motion compensation approaches based on the measurement of motion sensors, the residual uncompensated motion errors due to measurement instrument inaccuracies contribute to phase errors and hence degrade Synthetic Aperture Radar (SAR) images. This paper presents a model to compute the phase error caused by Inertial Measurement Unit (IMU) measurement inaccuracies. By analyzing SAR motion compensation method and the effect of lever arm, this model derives the con-tribution of each term of IMU inaccuracies towards the residual uncompensated motion errors and provides a method to calculate each order of the residual phase error. According to the model, com-puted results of the airborne X-band SAR system with POS AV510 accord closely with the actual image quality.

关键词： Synthetic Aperture Radar (SAR) Inertial Measurement Unit (IMU) Motion compen-sation Phase error

一种基于InSAR相干系数的SAR阴影提取方法

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武汉大学学报（信息科学版） 2005年第12期30卷 1063-1066页

作者：王健向茂生李绍恩中国科学院电子学研究所微波成像技术国家重点实验室

给出了一种新的阴影提取方法,根据阴影区域在InSAR相干系数图上的特性,利用Sigma滤波和最优阈值分割算法实现阴影的自动提取。实验结果表明,本方法是一种高效的阴影提取方法。

关键词： SAR InSAR 阴影相干系数 Sigma滤波最优阈值化

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城区地表形变差分TomoSAR监测方法

测绘学报 2016年第12期45卷 1413-1422页

作者：王爱春向茂生汪丙南中国科学院电子学研究所微波成像技术国家级重点实验室北京100190 中国科学院大学北京100049 中国资源卫星应用中心北京100094

压缩感知技术(CS)的差分TomoSAR技术解决了中高分辨率SAR数据在城区出现的叠掩问题,实现了城区地表形变信息的重构,但是该方法仅利用了目标的稀疏特性并没有考虑目标的结构特性,对具有这两种特性的目标进行重构时其性能较差。针对这一问... 详细信息

压缩感知技术(CS)的差分TomoSAR技术解决了中高分辨率SAR数据在城区出现的叠掩问题,实现了城区地表形变信息的重构,但是该方法仅利用了目标的稀疏特性并没有考虑目标的结构特性,对具有这两种特性的目标进行重构时其性能较差。针对这一问题,本文采用联合Khatri-Rao子空间和块压缩感知(KRS-BCS),提出了一种差分SAR层析成像方法。该方法依据目标的结构特性和重构观测矩阵具有的Khatri-Rao积性质,将稀疏结构目标的差分TomoSAR问题转化为Khatri-Rao子空间下的BCS问题,然后对目标进行块稀疏的l1/l2范数最优化求解,最后通过理论分析和仿真试验对分辨能力和重构估计性能进行了定性和定量评价,仿真结果表明本文所采用的KRS-BCS方法不仅保持了高分辨率的优点,而且有效地降低了虚假目标出现的概率,大幅度提高了散射点准确重构概率,切实可行地解决了CS方法的不足。应用实例研究中,利用34景Envisat卫星ASAR时间序列影像对日本千叶县茂原市城区进行地表形变监测,并以一等水准点和实时测量的GPS站点观测数据作为参考形变结果进行验证,试验结果表明采用KRS-BCS方法反演的结果与参考形变结果保持了良好的一致性且形变速率整体偏差也较小,实现了较高精度的城区地表形变估计。

关键词：城区地表形变差分TomoSAR技术 Khatri-Rao子空间块压缩感知

一种联合Khatri-Rao子空间与块稀疏压缩感知的差分SAR层析成像方法

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电子与信息学报 2017年第1期39卷 95-102页

作者：王爱春向茂生汪丙南中国科学院电子学研究所微波成像技术国家级重点实验室北京100190 中国科学院大学北京100049 中国资源卫星应用中心北京100094

虽然采用压缩感知技术(Compressive Sensing,CS)的差分SAR层析成像方法实现了4维空间信息的重构,但是此方法仅利用了目标的稀疏特性并没有考虑目标的结构特性,因此对同时具有稀疏特性和结构特性的目标进行重构时其性能较差。针对这一问... 详细信息

虽然采用压缩感知技术(Compressive Sensing,CS)的差分SAR层析成像方法实现了4维空间信息的重构,但是此方法仅利用了目标的稀疏特性并没有考虑目标的结构特性,因此对同时具有稀疏特性和结构特性的目标进行重构时其性能较差。针对这一问题,该文采用联合Khatri-Rao子空间和块压缩感知(Khatri-Rao Subspace and Block Compressive Sensing,KRS-BCS),提出一种差分SAR层析成像方法。该方法依据目标的结构特性和重构观测矩阵具有的Khatri-Rao积性质,将稀疏结构目标的差分SAR层析成像问题转化为Khatri-Rao子空间下的BCS问题,最后对目标进行块稀疏的l_1/l_2范数最优化求解。相比CS差分SAR层析成像方法,该方法不仅保持了CS差分SAR层析成像方法的高分辨率特点,而且其重构精度更高性能更优。仿真数据和ENVISAT星载ASAR数据以及地面GPS实测数据的试验结果验证了该方法的有效性。

关键词：差分SAR层析成像技术 Khatri-Rao子空间块压缩感知