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）...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.展开更多
This paper proposes a calibrated method for quasi-broadside side-looking mode SAR imaging with small squint angle and an improved method named as phase alignment algorithm of subaperture reference signal. The calibrat...This paper proposes a calibrated method for quasi-broadside side-looking mode SAR imaging with small squint angle and an improved method named as phase alignment algorithm of subaperture reference signal. The calibrated method adopts subaperture spotlighting algorithm of broadside mode to image the real data of quasi-broadside mode SAR, then based on the obtained image the small squint angle is estimated and the calibrated subaperture spotlighting algorithm of squint mode is employed to obtain the final image. The calibrated method can calibrate the abnormal region and obtain the correct image. The phase alignment algorithm of subaperture reference signal adjusts phases of respective subaperture reference signals in order to make them be in phase and constructs a new spotlighting window function for SAR imaging. Theoretical analysis shows that with the same sample data, the improved method can increase SAR imaging area in azimuth dimension. The methods are verified by the results of computer simulation.展开更多
Among Synthetic Aperture Radar(SAR)image formation algorithms,the chirp scaling algorithm(CSA)is computationally highly efficient and has been practically used.In this paper,how to implement the subaperture extended C...Among Synthetic Aperture Radar(SAR)image formation algorithms,the chirp scaling algorithm(CSA)is computationally highly efficient and has been practically used.In this paper,how to implement the subaperture extended CSA in a high resolution spotlight mode SAR is studied in detail.The procedures such as subaperture processing and azimuth processing are discussed.According to the problems presented when using the method(A.Moreira,et al,1996)to process spotlight SAR data,full formula expressions suitable for high squinted angles is presented.While point target simulation is analyzed,the method is validated by E SAR raw data.The results can be directly implemented in the design of SAR processors.展开更多
Spinal cord injury（SCI）with consecutive paralysis below the lesion level is a severe disorder affecting the patient for the rest of his or her life.So far,there is no known fundamental intervention strategy for effi...Spinal cord injury（SCI）with consecutive paralysis below the lesion level is a severe disorder affecting the patient for the rest of his or her life.So far,there is no known fundamental intervention strategy for efficiently helping those patients regain their motor abilities,despite intense research in this area.Thus,effective treatment for those patients is still an open question. A spinal cord injury is accompanied by a prima- ry, severe and irreversible neuronal cell death in the trauma region, fol- lowed by a secondary extensive cell necrosis in the lesion surrounding areas. Nevertheless, recent studies indicate that regeneration after spinal cord injury could be possible if three substantial steps are fulfilled： （1） reduction of the inhibitory environment at the SCI lesion site, （2） iden- tification of a neural substrate to establish new spinal circuits, and （3） support of these circuits to form permanent, functional motor, sensory, or autonomic connections （Dru and Hoh, 2015）.展开更多
This paper first studies the phase errors for fine-resolution spotlight mode SAR imaging and decomposes the phase errors into two kinds, one is caused by translation and the other by rotation. Mathematical analysis an...This paper first studies the phase errors for fine-resolution spotlight mode SAR imaging and decomposes the phase errors into two kinds, one is caused by translation and the other by rotation. Mathematical analysis and computer simulations show the above mentioned motion kinds and their corresponding damages on spotlight mode SAR imaging. Based on this analysis, a single PPP is introduced for spotlight mode SAR imaging with the PFA on the assumption that relative rotation between APC and imaged scene is uniform. The selected single point is used first to correct the quadratic and higher order phase errors and then to adjust the linear errors. After this compensation, the space-invariant phase errors caused by translation are almost corrected. Finally results are presented with the simulated data.展开更多
This paper investigates a novel approach based on the deramping technique for squinted sliding spotlight Synthetic Aperture Radar (SAR) imaging to resolve the azimuth spectrum aliasing problem. First of all, the prope...This paper investigates a novel approach based on the deramping technique for squinted sliding spotlight Synthetic Aperture Radar (SAR) imaging to resolve the azimuth spectrum aliasing problem. First of all, the properties of the azimuth spectrum and the squint angle impacts on the azimuth spectrum aliasing problem are analyzed. Based on the analysis result, an operation of filtering is added to the azimuth preprocessing step of traditional Two-Step Focusing Approach (TSPA) to resolve the azimuth folding problem and remove the influence of the squint angle on the azimuth spectrum aliasing problem. Then, a modified Range Migration Algorithm (RMA) is performed to obtain the precise focused image. Furthermore, the focused SAR image folding problem of traditional TSPA is illuminated in this paper. An azimuth post-processing step is proposed to unfold the aliased SAR image. Simulation experiment results prove that the proposed approach can solve the spectrum aliasing problem and process squinted sliding spotlight data efficiently.展开更多
For a synthetic aperture radar（SAR） system mounted on a geostationary Earth orbit（GEO） satellite, the track can be curvilinear. Thus, a bistatic SAR system based up on geostationary transmitter and ＂receive-only...For a synthetic aperture radar（SAR） system mounted on a geostationary Earth orbit（GEO） satellite, the track can be curvilinear. Thus, a bistatic SAR system based up on geostationary transmitter and ＂receive-only＂ SAR system onboard airplanes, namely GEO spaceborne-airborne bistatic（GEO SA-Bi SAR）, is significantly different from the traditional bistatic SAR. This paper mainly studies the resolution characteristic of the sliding spotlight GEO SA-Bi SAR system. Firstly, the common azimuth coverage and coherent accumulated time are theoretically analyzed in detail. Then,based on the gradient method, the accurate two dimensional resolution of a GEO SA-Bi SAR system is analytically calculated. Finally, the simulation data show the correctness and effectiveness of the proposed resolution analysis method.展开更多
FEBRUARY,2016 Regulations Concerning Menstrual Pain Leave a Step in the Right Direction Women in Anhui Province can take 1-2 days off when suffering menstrual pain so long as they provide a medical certificate,accordi...FEBRUARY,2016 Regulations Concerning Menstrual Pain Leave a Step in the Right Direction Women in Anhui Province can take 1-2 days off when suffering menstrual pain so long as they provide a medical certificate,according to the latest labor regulations established by the Anhui provincial government.Anhui is not the only province to take this stance.Other regions,such as Jiangsu Province and Guangdong Province,are also展开更多
Advances in liver transplantation for hepatocellular carcinoma Dr.Ronald W.Busuttil from University of California,Los Angles,described progress in liver transplantation for hepatocellular carcinoma(HCC).Three
Li Ming(李明)Prof.Li is a tenured professor in the School of Materials Science and Engineering at Shanghai Jiao Tong University,and the founder of the Institute of Electronics Materials and Technology.He received his ...Li Ming(李明)Prof.Li is a tenured professor in the School of Materials Science and Engineering at Shanghai Jiao Tong University,and the founder of the Institute of Electronics Materials and Technology.He received his Ph D degree from Kyushu Institute of Technology(Japan)in 1998.He then worked in a Japanese manufacturing company Mitsui High-Tec Inc.for many years.Currently,his research interest mainly focused 3D packaging materials and technology(lead-free solder,interconnection,low temperature bonding),nanostructured materials and functional thin films preparation routed by electrochemical method(electrodeposition,electro-grafting).展开更多
Renjie Chen (陈人杰)Prof. Chen is a full professor, doctoral supervisor of Beijing Institute of Technology. He is the director of Innovation Center for Advanced Energy Materials and Smart Batteries of Advanced Technol...Renjie Chen (陈人杰)Prof. Chen is a full professor, doctoral supervisor of Beijing Institute of Technology. He is the director of Innovation Center for Advanced Energy Materials and Smart Batteries of Advanced Technology Research Institute.展开更多
In the 2014 movie, Spotlight, religion, represented by the Catholic Church, has an expected place for the community--the City of Boston, Massachusetts. And, the community of Boston, represented by the institution of a...In the 2014 movie, Spotlight, religion, represented by the Catholic Church, has an expected place for the community--the City of Boston, Massachusetts. And, the community of Boston, represented by the institution of a free press, has a corresponding expectation of the Church. In this paper, I explore these expectations as they are identified in the Oscar winning film, Spotlight.展开更多
基金Supported by the National Science Fund for Distinguished Young Scholars (Grant No. 60725103)the National Natural Science Foundation ofChina (Grant No. 60602015)+1 种基金the National Key Laboratory Foundation (Grant No. 9140C1903030603)the Knowledge Innovation Programof Chinese Academy of Sciences (Grant No. 07QNCX-1154)
文摘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.
文摘This paper proposes a calibrated method for quasi-broadside side-looking mode SAR imaging with small squint angle and an improved method named as phase alignment algorithm of subaperture reference signal. The calibrated method adopts subaperture spotlighting algorithm of broadside mode to image the real data of quasi-broadside mode SAR, then based on the obtained image the small squint angle is estimated and the calibrated subaperture spotlighting algorithm of squint mode is employed to obtain the final image. The calibrated method can calibrate the abnormal region and obtain the correct image. The phase alignment algorithm of subaperture reference signal adjusts phases of respective subaperture reference signals in order to make them be in phase and constructs a new spotlighting window function for SAR imaging. Theoretical analysis shows that with the same sample data, the improved method can increase SAR imaging area in azimuth dimension. The methods are verified by the results of computer simulation.
基金National Natural Science F oundation of china(68931040)
文摘Among Synthetic Aperture Radar(SAR)image formation algorithms,the chirp scaling algorithm(CSA)is computationally highly efficient and has been practically used.In this paper,how to implement the subaperture extended CSA in a high resolution spotlight mode SAR is studied in detail.The procedures such as subaperture processing and azimuth processing are discussed.According to the problems presented when using the method(A.Moreira,et al,1996)to process spotlight SAR data,full formula expressions suitable for high squinted angles is presented.While point target simulation is analyzed,the method is validated by E SAR raw data.The results can be directly implemented in the design of SAR processors.
基金supported by DFG Grant KFO 213 and the "ElseKr?ner-Fresenius-Stiftung" to JG
文摘Spinal cord injury（SCI）with consecutive paralysis below the lesion level is a severe disorder affecting the patient for the rest of his or her life.So far,there is no known fundamental intervention strategy for efficiently helping those patients regain their motor abilities,despite intense research in this area.Thus,effective treatment for those patients is still an open question. A spinal cord injury is accompanied by a prima- ry, severe and irreversible neuronal cell death in the trauma region, fol- lowed by a secondary extensive cell necrosis in the lesion surrounding areas. Nevertheless, recent studies indicate that regeneration after spinal cord injury could be possible if three substantial steps are fulfilled： （1） reduction of the inhibitory environment at the SCI lesion site, （2） iden- tification of a neural substrate to establish new spinal circuits, and （3） support of these circuits to form permanent, functional motor, sensory, or autonomic connections （Dru and Hoh, 2015）.
基金Supported by the Aeronautic Scientific Foundation(No.98F5118)
文摘This paper first studies the phase errors for fine-resolution spotlight mode SAR imaging and decomposes the phase errors into two kinds, one is caused by translation and the other by rotation. Mathematical analysis and computer simulations show the above mentioned motion kinds and their corresponding damages on spotlight mode SAR imaging. Based on this analysis, a single PPP is introduced for spotlight mode SAR imaging with the PFA on the assumption that relative rotation between APC and imaged scene is uniform. The selected single point is used first to correct the quadratic and higher order phase errors and then to adjust the linear errors. After this compensation, the space-invariant phase errors caused by translation are almost corrected. Finally results are presented with the simulated data.
文摘This paper investigates a novel approach based on the deramping technique for squinted sliding spotlight Synthetic Aperture Radar (SAR) imaging to resolve the azimuth spectrum aliasing problem. First of all, the properties of the azimuth spectrum and the squint angle impacts on the azimuth spectrum aliasing problem are analyzed. Based on the analysis result, an operation of filtering is added to the azimuth preprocessing step of traditional Two-Step Focusing Approach (TSPA) to resolve the azimuth folding problem and remove the influence of the squint angle on the azimuth spectrum aliasing problem. Then, a modified Range Migration Algorithm (RMA) is performed to obtain the precise focused image. Furthermore, the focused SAR image folding problem of traditional TSPA is illuminated in this paper. An azimuth post-processing step is proposed to unfold the aliased SAR image. Simulation experiment results prove that the proposed approach can solve the spectrum aliasing problem and process squinted sliding spotlight data efficiently.
基金supported by the National Natural Science Foundation of China(61271342)
文摘For a synthetic aperture radar（SAR） system mounted on a geostationary Earth orbit（GEO） satellite, the track can be curvilinear. Thus, a bistatic SAR system based up on geostationary transmitter and ＂receive-only＂ SAR system onboard airplanes, namely GEO spaceborne-airborne bistatic（GEO SA-Bi SAR）, is significantly different from the traditional bistatic SAR. This paper mainly studies the resolution characteristic of the sliding spotlight GEO SA-Bi SAR system. Firstly, the common azimuth coverage and coherent accumulated time are theoretically analyzed in detail. Then,based on the gradient method, the accurate two dimensional resolution of a GEO SA-Bi SAR system is analytically calculated. Finally, the simulation data show the correctness and effectiveness of the proposed resolution analysis method.
文摘FEBRUARY,2016 Regulations Concerning Menstrual Pain Leave a Step in the Right Direction Women in Anhui Province can take 1-2 days off when suffering menstrual pain so long as they provide a medical certificate,according to the latest labor regulations established by the Anhui provincial government.Anhui is not the only province to take this stance.Other regions,such as Jiangsu Province and Guangdong Province,are also
文摘Advances in liver transplantation for hepatocellular carcinoma Dr.Ronald W.Busuttil from University of California,Los Angles,described progress in liver transplantation for hepatocellular carcinoma(HCC).Three
文摘Li Ming(李明)Prof.Li is a tenured professor in the School of Materials Science and Engineering at Shanghai Jiao Tong University,and the founder of the Institute of Electronics Materials and Technology.He received his Ph D degree from Kyushu Institute of Technology(Japan)in 1998.He then worked in a Japanese manufacturing company Mitsui High-Tec Inc.for many years.Currently,his research interest mainly focused 3D packaging materials and technology(lead-free solder,interconnection,low temperature bonding),nanostructured materials and functional thin films preparation routed by electrochemical method(electrodeposition,electro-grafting).
文摘Renjie Chen (陈人杰)Prof. Chen is a full professor, doctoral supervisor of Beijing Institute of Technology. He is the director of Innovation Center for Advanced Energy Materials and Smart Batteries of Advanced Technology Research Institute.
文摘In the 2014 movie, Spotlight, religion, represented by the Catholic Church, has an expected place for the community--the City of Boston, Massachusetts. And, the community of Boston, represented by the institution of a free press, has a corresponding expectation of the Church. In this paper, I explore these expectations as they are identified in the Oscar winning film, Spotlight.
