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Analysis of phase preservation and interferometric offset test in sparse SAR imaging

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science china(Information sciences) 2024年第2期67卷 219-231页

作者： Zhongqiu XU bingchen zhang Guangzuo LI Xueli ZHAN Yanfei BAO yirong wu Key laboratory of Spatial Information Processing and Application System technology Chinese Academy of Sciences Aerospace Information Research Institute Chinese Academy of Sciences School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of Sciences PLA Academy of Military sciences

Sparse synthetic aperture radar(SAR) imaging has emerged as a reliable microwave imaging scheme in the recent decade and excels in down-sampling reconstruction and full-sampling performance improvements such as noise, sidelobe, speckle, and ambiguity suppression. To utilize complex image products of sparse reconstruction for improvement in polarimetric, interferometric, and tomographic SAR imaging, it is necessary to evaluate the phase preservation of sparse SAR imaging. In this study, we first introduce the general alternating direction method of multipliers(ADMM) as the universal framework for sparse reconstruction algorithms and adopt chirp scaling algorithm(CSA)-based azimuth-range decouple operators to avoid expensive data storage and processing. Further, we theoretically analyze the phase preservation of the sparse reconstruction algorithm through a comparison with the reconstruction results of CSA. Finally,we conduct the interferometric offset test on the sparse reconstruction results of simulated and real Gaofen-3(GF-3) SAR data, demonstrating the phase-preserving ability of sparse methods.

关键词： sparse SAR imaging phase preservation interferometric offset test general ADMM azimuth-range decouple

Multi-channel SAR imaging based on distributed compressive sensing

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science china(Information sciences) 2012年第2期55卷 245-259页

作者： LIN YueGuan1,2,3,zhang bingchen1,2,JIANG Hai1,2,3,hong wen1,2 & wu yirong1,2 1National Key laboratory of science and technology on microwave imaging,beijing 100190,china 2Institute of Electronics,Chinese Academy of sciences,beijing 100190,china 3Graduate University of Chinese Academy of sciences,beijing 100049,china 1. National Key laboratory of science and technology on microwave imaging Beijing 100190 China2. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China3. Graduate University of Chinese Academy of Sciences Beijing 100049 China

The rapid development of compressive sensing(CS)shows that it is possible to recover a sparse signal from very limited *** aperture radar(SAR)imaging based on CS can reconstruct the target scene with a reduced number of collected samples by solving an optimization *** multi-channel SAR imaging based on CS,each channel requires sufficient samples for separate imaging and the total number of samples could still be *** propose an imaging algorithm based on distributed compressive sensing(DCS)that reconstructs scenes jointly under multiple ***-channel SAR imaging based on DCS not only exploits the sparsity of the target scene,but also exploits the correlation among *** requires significantly fewer samples than multi-channel SAR imaging based on *** multiple channels offer different sampling rates,DCS joint processing can reconstruct target scenes with a much more flexible allocation of the number of measurements offered by each channel than that used in separate CS processing.

关键词： synthetic aperture radar multi-channel synthetic aperture radar compressive sensing distributed compressive sensing

Influence factors of sparse microwave imaging radar system performance:approaches to waveform design and platform motion analysis

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science china(Information sciences) 2012年第10期55卷 2301-2317页

作者： zhang Zhe 1,2,3,zhang bingchen 1,2,JIANG ChengLong 1,2,3,XIANG Yin 1,2,hong wen 1,2 & wu yirong 1,2 1 science and technology on microwave imaging laboratory,beijing 100190,china 2 Institute of Electronics,Chinese Academy of sciences,beijing 100190,china 3 Graduate University,Chinese Academy of sciences,beijing 100190,china 1. science and technology on microwave imaging laboratory Beijing 100190 China 2. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China 3. Graduate University Chinese Academy of Sciences Beijing 100190 China

Sparse microwave imaging radar is a newly developed concept of microwave imaging system,which tries to combine the traditional radar imaging system with sparse signal processing theories,achieving the aim of reducing the complexity of microwave imaging systems and enhancing the system *** this paper,we introduce some basic concepts of sparse signal processing theory,and then apply it to the traditional radar imaging system to get the mathematical model of sparse microwave imaging *** analyze the factors that determine the performance of sparse microwave imaging radar,including scene,waveform and *** to the radar model,we analyze how these factors influence the radar system and how to optimize *** results of the sparse microwave imaging radar system are also provided.

关键词： sparse microwave imaging radar synthetic aperture radar compressive sensing Lq regularization waveform design

Experimental results and analysis of sparse microwave imaging from spaceborne radar raw data

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science china(Information sciences) 2012年第8期55卷 1801-1815页

作者： JIANG ChengLong1,2,3,zhang bingchen1,2,zhang Zhe1,2,3,hong wen1,2&wu yirong1,2 1S cience and technology on microwave imaging laboratory,beijing 100190,china 2I nstitute of Electronics,Chinese Academy of sciences,beijing 100190,china 3G raduate University of Chinese Academy of sciences,beijing 100190,china 1. science and technology on microwave imaging laboratory Beijing 100190 China2. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China3. Graduate University of Chinese Academy of Sciences Beijing 100190 China

Sparse microwave imaging is a novel radar framework aiming to bring revolutions to the microwave imaging according to the theory of sparse signal *** compressive sensing(CS)is introduced to synthetic aperture radar(SAR)imaging in recent years,the current SAR sparse imaging methods have shown their advantages over the traditional matched filtering ***,the requirement for these methods to process the compressed range data results in the increase of the hardware *** the SAR sparse imaging method that directly uses the raw data is *** paper describes the method of SAR sparse imaging with raw data directly,presents the analysis of the signal-to-noise ratio(SNR)in the echo signal by combining the traditional radar equation with the compressive sensing theory,and provides the tests on 2-D simulated SAR *** simulation results demonstrate the validity of the SNR analysis,and the good performance of the proposed method while a large percentage of the raw data is *** experiment with RadarSat-1 raw data is also carried out to show the feasibility of processing the real SAR data via the method proposed in this *** method is helpful for designing new SAR systems.

关键词： sparse microwave imaging synthetic aperture radar(SAR)imaging compressive sensing signalto-noise ratio raw data

Synthetic aperture radar tomography sampling criteria and three-dimensional range migration algorithm with elevation digital spotlighting

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science in china(Series F) 2009年第1期52卷 100-114页

作者： TAN WeiXian1,2,3?, hong wen1,2, WANG YanPing1,2, LIN Yun1,2,3 & wu yirong1,2 1 State Key laboratory of microwave imaging technology, beijing 100190, china 2 Institute of Electronics, Chinese Academy of sciences, beijing 100190, china 3 Graduate School, Chinese Academy of sciences, beijing 100190, china State Key laboratory of microwave imaging technology Beijing 100190 China Institute of Electronics Chinese Academy of Sciences Beijing 100190 China Graduate School Chinese Academy of Sciences Beijing 100190 China

Based on the general geometric model of multi-baseline Synthetic Aperture Radar Tomography （TomoSAR）, the three-dimensional （3-D） sampling criteria, the analytic expression of the 3-D Point Spread Function （PSF） and the 3-D resolution are derived in the 3-D wavenumber domain in this paper. Considering the relationship between the observation geometry and the size of illuminated scenario, a 3-D Range Migration Algorithm with Elevation Digital Spotlighting （RMA-EDS） is proposed. With this algorithm 3-D images of the area of interest can be directly and accurately reconstructed in the 3-D space avoiding the complex operations of 3-D geometric correction. Finally, theoretical analyses and simulation results are presented to demonstrate the shift-varying property of the 3-D PSF and the spatialvarying property of the 3-D resolution and to demonstrate the validity of the 3-D RMA-EDS.

关键词： synthetic aperture radar tomography (TomoSAR) three-dimensional (3-D) SAR imaging 3-D sampling criteria 3-D resolution,3-D range migration algorithm with elevation digital spotlighting (RMA-EDS)

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Maximal effective baseline for polarimetric interferometric SAR forest height estimation

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science china(Information sciences) 2012年第4期55卷 867-876页

作者： ZHOU YongSheng 1,2,3,hong wen 1,2,WANG YanPing 1,2 & wu yirong 1,2 1 National Key laboratory of science &technology on microwave imaging,beijing 100190,china 2 Institute of Electronics,Chinese Academy of sciences,beijing 100190,china 3 Academy of Opto-Electronics,Chinese Academy of sciences,beijing 100094,china 1. National Key laboratory of science & technology on microwave imaging Beijing 100190 China2. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China3. Academy of Opto-Electronics Chinese Academy of Sciences Beijing 100094 China

The concepts of critical baseline and maximal effective baseline have been defined for interferometric SAR (InSAR) DEM application based on the spatial decorrelation (which is a function of baseline).This paper puts forward these two concepts to polarimetric interferometric SAR (Pol-InSAR) forest height estimation *** application makes use of volume decorrelation,which is also a function of *** both the spatial decorrelation and volume decorrelation are considered to determine Pol-InSAR critical and maximal effective *** various decorrelation effects are *** the calculation formula of Pol-InSAR maximal effective baseline are presented and compared to that of *** validation,RVoG-based and PolSARpro-based simulation data and DLR ESAR data are *** concept of Pol-InSAR maximal effective baseline is of practical significance in selection of Pol-InSAR image pairs as well as in the design of further Pol-InSAR systems.

关键词： Pol-InSAR maximal baseline forest height estimation

Studies on MB-SAR 3D imaging algorithm using Yule-Walker method

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science china(Information sciences) 2010年第9期53卷 1848-1859页

作者： WANG Bin1,2*,WANG YanPing1,hong wen1,TAN WeiXian1,2 & wu yirong1 1National Key laboratory of microwave imaging technology,Institute of Electronics,Chinese Academy of sciences,beijing 100190,china 2Graduate University of Chinese Academy of sciences,beijing 100049,china 1. National Key laboratory of microwave imaging technology Institute of Electronics Chinese Academy of Sciences Beijing 100190 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Multibaseline synthetic aperture radar(MB-SAR) can form a synthetic aperture in the height direction with multiple parallel observations,so it has the resolving capability in the height direction and can realize three-dimensional(3D) imaging for the *** analytic model of MB-SAR based on spectrum estimation is analyzed in this *** on the more general geometric model,we derive the signal model for MB-SAR 3D *** then Yule-Walker algorithm is proposed to realize MB-SAR 3D imaging meanwhile the principle is analyzed and the steps of Yule-Walker algorithm are *** algorithm can get the 3D image of the target with high resolution using fewer ***,the experimental results of MB-SAR 3D imaging using Yule-Walker algorithm are presented,which are generated with the simulated data and the data collected in anechoic chamber.

关键词： MB-SAR 3D SAR imaging algorithm SAR spectrum estimation Yule-Walker method

Effect of Nb-content on the corrosion resistance of Co-free high entropy alloys in chloride environment

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Tungsten 2024年第4期6卷 778-793页

作者： Peng-Fei Dai Yang zhang Sergey Rogozhkin Ji-hong Han Shu-wen Li Zhong-wu zhang Key laboratory of Superlight Materials and Surface technology Ministry of Education College of Materials Science and Chemical Engineering Harbin Engineering University National Research Nuclear University “MEPh I” National Research Center “Kurchatov Institute”

This study investigated the effect of Nb-content on the corrosion behavior of the Al7Cr20Fe35-xNi35Mo3Nbx（x=0,1 and 2）high-entropy alloys in a *** results indicated that only the face centered cubic phase existed in the NbO and Nbl alloys,while the emergence of Laves phase was observed when Nb-content reached 2 at.%.The NbO and Nb1alloys exhibited pitting corrosion,while the NiAl-rich phase experienced localized preferential corrosion in the Nb2 *** electrochemical results revealed that the corrosion current density of the Nbx（x=0,1 and 2） alloys fell within the range of 10-8-10-7A·cm-2,with a pitting corrosion potential exceeding 700 ***,the Nb1 alloy exhibited the most impressive corrosion resistance,as its corrosion current density(7 × 10-8A·cm-2) was merely half that of 316LN stainless *** is attributed to its rapid passivation process,resulting in the development of a protective film characterized by an increased Cr2O3/Al2O3+Cr（OH）*** study highlighted that the addition of Nb contributed to gram refinement,decreased corrosion current density,and elevated pitting potential,favoring passivation and improving corrosion ***,excessive Nb-content resulted in the emergence of the Laves phase,inducing galvanic corrosion and diminishing resistance to corrosion.

关键词： Corrosion High entropy alloys Microstructure Niobium Passive film

The use of laser ranging to measure space debris

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Research in Astronomy and Astrophysics 2012年第2期12卷 212-218页

作者： Zhong-Ping zhang 1,2,Fu-Min Yang 1,Hai-Feng zhang 1,Zhi-Bo wu 1,2,Ju-Ping Chen 1,2,Pu Li 1 and wen-Dong Meng 1 1 Shanghai Astronomical Observatory,Chinese Academy of sciences,Shanghai 200030,china 2 Key laboratory of Space Object and Debris Observation,Chinese Academy of science,Nanjing 210008,china Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Key laboratory of Space Object and Debris Observation Chinese Academy of Science Nanjing 210008 China

Space debris is a major problem for all the nations that are currently active in space. Adopting high-precision measuring techniques will help produce a reliable and accurate catalog for space debris and collision avoidance. Laser ranging is a kind of real-time measuring technology with high precision for space debris observation. The first space-debris laser-ranging experiment in china was performed at the Shanghai Observatory in July 2008 with a ranging precision of about 60-80 cm. The experi- mental results showed that the return signals from the targets with a range of 900 km were quite strong, with a power of 40W （2J at 20 Hz） using a 10ns pulse width laser at 532 nm wavelength. The performance of the preliminary laser ranging system and the observed results in 2008 and 2010 are also introduced.

关键词： astrometry - catalogs - space debris - laser ranging - observation

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