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Two Dimensional Position Correction algorithm for High-Squint Synthetic Aperture Radar in wavenumber domain algorithm

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REMOTE SENSING 2025年第6期17卷 1015-1015页

作者： Wang, Shuai Song, Chen Wang, Bingnan Chen, Jie Yang, Lixia Huang, Zhixiang Anhui Univ Sch Elect & Informat Engn Hefei 230601 Peoples R China Chinese Acad Sci Aerosp Informat Res Inst Natl Key Lab Microwave Imaging Beijing 100045 Peoples R China

In the traditional high squint angle omega-k imaging algorithm, the impact of a high squint angle on azimuth and range positioning is not considered but does include two aspects: the azimuth position shift caused by a high squint angle and the impact of Stolt interpolation on range positioning under a high squint angle. From the viewpoint of the geometric features of data acquisition in high-squint SAR and the characteristics of the omega-k imaging algorithm, this paper analyzes the causes of azimuth position offsets and range position offsets. According to the causes, closed-form mathematical expressions quantifying these coupled spatial distortions are derived. The omega-k imaging algorithm process is adjusted, and the correction factor is embedded into the imaging process to achieve offset-free, high-resolution imaging in the case of high-squint SAR.

关键词： high-squint synthetic aperture radar (SAR) wavenumber domain algorithm position offset and correction

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A Precise wavenumber domain algorithm for Near Range Microwave Imaging by Cross MIMO Array

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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 2019年第4期67卷 1316-1326页

作者： Zhou, Jianxiong Zhu, Rongqiang Jiang, Ge Zhao, Lei Cheng, Binbin Natl Univ Def Technol Natl Key Lab Sci & Technol ATR Sch Elect Sci Changsha 410073 Hunan Peoples R China China Acad Engn Phys Inst Elect Engn Mianyang 621900 Peoples R China China Acad Engn Phys Microsyst & Terahertz Res Ctr Chengdu 610200 Sichuan Peoples R China

An electronically large planar antenna with wideband illumination retrieves 3-D microwave image with high resolution. Cross multi-input-multi-output (MIMO) topology is commonly used to produce the effective planar array at a reasonable cost and complexity. However, the imaging algorithm for effective monostatic array will cause distortion and dispersion in near range imaging applications. In this paper, an efficient and precise algorithm for near range imaging by cross MIMO array is proposed. The integrals over the transmitting and receiving arrays are carried out in the wavenumber domain to improve efficiency. No approximation is made to further decouple the space and wavenumber variables so the reconstructed image precisely retains both intensity and phase information. The algorithm achieves the same imaging quality as the back-propagation algorithm at the computation complexity of O(N(4)lgN). It can also be implemented to boundary arrays by coherent subarray superposition. Experiments using both simulated and measured data verify its performance. The point spread function and resolution of cross MIMO topology are discussed based on the images reconstructed by this algorithm using measured data.

关键词： Cross multi-input-multi-output (MIMO) topology microwave imaging near range imaging wavenumber domain algorithm

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Expansion of Output Spatial Extent in the wavenumber domain algorithms for Near-Field 3-D MIMO Radar Imaging

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REMOTE SENSING 2025年第7期17卷 1287-1287页

作者： Gong, Yifan Zhai, Limin Jia, Yan Liu, Yongqing Zhang, Xiangkun Chinese Acad Sci Natl Space Sci Ctr Key Lab Microwave Remote Sensing Beijing 100190 Peoples R China Univ Chinese Acad Sci Sch Elect Elect & Commun Engn Beijing 100049 Peoples R China

Microwave camera provides 3-D high-resolution radar images at video frame rates, enabling the capture of dynamic target features. Multiple-input-multiple-output (MIMO) array-based 3-D radar imaging system requires fewer antennas, which effectively reduces hardware costs. Due to the limited computational resources of the miniaturized MIMO microwave camera, real-time processing of a large amount of 3-D echo data requires an imaging algorithm that has both real-time performance and large output spatial extent. This paper presents the limited output spatial extent and spatial aliasing in existing MIMO wavenumber domain algorithms through theoretical derivation and simulation. To suppress aliasing while expanding the output spatial extent, an optimization approach for the wavenumber domain algorithms is proposed. The improved wavenumber domain algorithms divide the target area into multiple sub-blocks, and a broader range of imaging results is obtained through independent imaging of the sub-blocks and a spatial aliasing suppression filter. Simulation results show that the improved wavenumber domain algorithms effectively suppress the aliasing energy of each sub-block while maintaining the advantage of low time complexity. Expansion of output spatial extent in existing MIMO wavenumber domain algorithms is achieved.

关键词： multiple-input-multiple-output (MIMO) near-filed imaging wavenumber domain algorithm large scene sub-block imaging

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Performance Analysis of wavenumber domain algorithms for Highly Squinted SAR

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IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING 2023年 16卷 1563-1575页

作者： Chen, Xing Hou, Zhenyu Dong, Zhen He, Zhihua Natl Univ Def Technol Coll Elect Sci & Engn Changsha 410073 Peoples R China

wavenumber domain algorithms have unique advantages in processing highly squinted synthetic aperture radar data. This article studies the performance of three commonly used wavenumber domain algorithms including the classical wavenumber domain (CWD) algorithm, extended wavenumber domain (EWD) algorithm, and squint wavenumber domain (SWD) algorithm. First, the wavenumber domain signal expression under the zero-Doppler and acquisition-Doppler reference geometries are both derived. Second, the internal relationship between three wavenumber domain algorithms is analyzed. A new interpretation of the relationship between the three algorithms and an interpolation strategy are given. The analysis not only provides a deeper understanding of the three algorithms, but also provides a basis for comparing them. Then, the performance of the three wavenumber domain algorithms is evaluated from the perspectives of computational complexity, image quality, and geometric position through theoretical analysis and simulation experiments. Aiming at the problem that the range and azimuth profiles are not orthogonal, a method to calculate resolution and extract profile is proposed. The results show that all three algorithms can obtain a well-focused images if full-resolution interpolation is performed, and the computational complexities of CWD and SWD are less than that of EWD.

关键词： Synthetic aperture radar Azimuth Geometry Doppler effect Approximation algorithms Interpolation Radar imaging Highly squinted synthetic aperture radar (SAR) stolt mapping wavenumber domain algorithm

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EFFICIENT IMAGING algorithm FOR RAIL-SAR WITH K-SPACE UNDERSAMPLING

EFFICIENT IMAGING ALGORITHM FOR RAIL-SAR WITH K-SPACE UNDERS...

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IEEE International Geoscience and Remote Sensing Symposium (IGARSS)

作者： Zhou JianXiong Li LongChao Zhu RongQiang Tian JiaHao Natl Univ Def Technol ATR Lab Changsha Peoples R China Southwest Elect & Telecommun Technol Res Inst Chengdu Peoples R China

ISBN: (数字)9781665427920

ISBN: (纸本)9781665427920

In rail-SAR systems, the synthetic aperture length is always much shorter than the azimuth scope of the imaging scene. To implement wavenumber domain algorithms, the aperture has to be zero-padded to avoid undersampling in the azimuth spectrum. In this paper, the space and frequency coupling in rail-SAR geometry is analyzed and an efficient omega K algorithm is proposed which uses demodulation, interpolation and modulation steps to retrieve information from the undersampled spectrum. We also propose to fold up the azimuth spectrum to avoid oversampling in image azimuth direction. This algorithm greatly reduces the memory occupation and computation load. Measurements of an outdoor scene verify its advantages in computational efficiency, image quality and phase preservation ability.

关键词： rail SAR imaging short synthetic aperture wavenumber domain algorithm azimuth spectrum undersampling

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Efficient Near-Field Imaging Using Cylindrical MIMO Arrays

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2021年第6期57卷 3648-3660页

作者： Li, Shiyong Wang, Shuoguang Amin, Moeness G. Zhao, Guoqiang Beijing Inst Technol Beijing Key Lab Millimeter Wave & Terahertz Techn Beijing 100081 Peoples R China Villanova Univ Ctr Adv Commun Villanova PA 19085 USA

Multiple-input-multiple-output (MIMO) array-based millimeter-wave (MMW) imaging has a tangible prospect in applications of concealed weapons detection. A near-field imaging algorithm based on wavenumber domain processing is proposed for a cylindrical MIMO array scheme with uniformly spaced transmit and receive antennas over both the vertical and horizontal-arc directions. The spectrum aliasing associated with the proposed MIMO array is analyzed through a zero-filling discrete-time Fourier transform. The analysis shows that an undersampled array can be used in recovering the MMW image by a wavenumber domain algorithm. The requirements for the antenna interelement spacing of the MIMO array are delineated. Numerical simulations as well as comparisons with the backprojection algorithm are provided to demonstrate the effectiveness of the proposed method.

关键词： MIMO communication Imaging Antenna arrays Radar imaging Receiving antennas Millimeter wave radar Fourier transforms Backprojection (BP) algorithm millimeter-wave (MMW) imaging multiple-input-multiple-output (MIMO) array spectrum aliasing wavenumber domain algorithm

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Cylindrical MIMO Array-Based Near-Field Microwave Imaging

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IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 2021年第1期69卷 612-617页

作者： Li, Shiyong Wang, Shuoguang An, Qiang Zhao, Guoqiang Sun, Houjun Beijing Inst Technol Beijing Key Lab Millimeter Wave & Terahertz Techn Beijing 100081 Peoples R China Fourth Mil Med Univ Dept Biomed Engn Xian 710032 Peoples R China

Microwave/millimeter-wave imaging has a wide prospect in applications of concealed weapons detection. The main problem of the existing techniques lies in the contradiction between the imaging speed and the system cost. In this respect, a cylindrical sparse multipleinput-multiple-output (MIMO) array topology is proposed, which has no mechanical scanning so as to achieve fast sampling process. Furthermore, it can provide more angular observations than the mainly used systems with a planar aperture. To speed up the image reconstruction process, a phase center approximation-based transformation is made to convert the multistatic sampling scheme to its monostatic counterpart for which there are more fast and tractable imaging algorithms. Then, a phase calibration method is presented after we analyze the error of such an equivalence. In so doing, the cylindrical MIMO topology is transformed into an approximate monostatic one. Finally, a wavenumber domain algorithm is employed to attain the fast image reconstruction. Numerical simulations are provided to demonstrate the performance improvement of the proposed technique.

关键词： Microwave imaging monostatic multiple-input-multiple-output (MIMO) array multistatic wavenumber domain algorithm

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Security Imaging for Multi-Target Screening Based on Adaptive Scene Segmentation With Terahertz Radar

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IEEE SENSORS JOURNAL 2019年第7期19卷 2675-2684页

作者： Gui, Shuliang Li, Jin Pi, Yiming Univ Elect Sci & Technol China Sch Informat & Commun Engn Qingshuihe Campus Chengdu 611731 Sichuan Peoples R China

In this paper, a terahertz (THz) radar security imaging method for multi-target screening is proposed. This imaging system is constituted of several transceivers to get multi-angle echo data. Through aperture synthesis and target detection processing of the multi-angle radar echo data, the multi-target scene can be segmented into several subscenes with each single target inside. In order to fast reconstruct the images of subscenes without the hypothesis of plane wave decomposition, which can cause severe defocus and distortion at the edge of THz radar near-field imaging results, wavenumber domain algorithm is modified for parallel processing of all subscenes data with the center locations of subscenes. Furthermore, convolution integral in slow time is used to speed up the processing of subscenes imaging with fast Fourier transform. Simulation results are analyzed and compared to demonstrate the performance and effectiveness of our method. Moreover, verifiable experiments are designed for proof-of-concept, where imaging scenes are rotating along with a fixed speed turntable. The experimental data are transmitted and received by a stationary THz radar, which operates at 340 GHz with the bandwidth of 28.8 GHz and the output peak power of 5 mW.

关键词： Radar imaging terahertz(THz) radar multi-target security screening adaptive scene segmentation wavenumber domain algorithm

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Multi-polarized Millimeter-Wave Imaging for Concealed Weapon Detection 9

Multi-polarized Millimeter-Wave Imaging for Concealed Weapon...

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9th IEEE International Conference on Microwave and Millimeter Wave Technology (ICMMT)

作者： Li, Xun Li, Shiyong Zhao, Guoqiang Sun, Houjun Beijing Inst Technol Beijing Key Lab Millimeter Wave & Terahertz Tech Beijing 100081 Peoples R China

ISBN: (纸本)9781467389839

Millimeter-wave (MMW) imaging techniques have been used for the detection of concealed weapons and contraband carried on personnel at airports and other secure locations. In this paper, the multi-polarized MMW imaging technique is researched, which can provide more target information. A test system is built with vector network analyzer (VNA) to verify the feasibility of this imaging technique for concealed weapon detection. The wavenumber domain algorithm is used to reconstruct the MMW images. Experiment results are provided to

关键词： millimeter-wave imaging multi-polarization vector network analyzer (VNA) wavenumber domain algorithm

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A Novel wavenumber domain SAR Imaging algorithm Based on the Fractional Fourier Transform

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Chinese Journal of Electronics 2014年第4期23卷 866-870页

作者： XU Huaping XIAO Zhongyuan GAO Jing LI Chunsheng Department of Electronic and Information Engineering Beihang University

The conventional wavenumber domain algorithm(WDA) employs Fast Fourier transform(FFT) to implement matched filter. It is characterized by its high precision SAR imaging. Compared with FFT, Fractional Fourier transform(Fr FT) can provide lower and narrower sidelobes when it is applied to compress chirp signals at the optimal transform. This paper proposed a novel SAR imaging algorithm, termed Fr WDA which replaces FFT in WDA with Fr FT. The Fr WDA was derived and its implementation was presented. How to choose the optimal transformation order was given subsequently. The Fr WDA preserves high precision focusing, and has better performance on sidelobe suppression. The Fr WDA is more suitable for the high precision SAR imaging, especially in target detection and recognition. Simulation results demonstrate that Fr WDA provides better performance on focusing and sidelobe suppression compared with the classical FFT-based WDA.

关键词： SAR imaging wavenumber domain algorithm FFT Fractional Fourier transform sidelobe suppression

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