The Experts below are selected from a list of 80457 Experts worldwide ranked by ideXlab platform
Yang Sun - One of the best experts on this subject based on the ideXlab platform.
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a novel inverse synthetic aperture radar imaging method for maneuvering targets based on modified chirp fourier transform
Applied Sciences, 2018Co-Authors: Yongping Wang, Hongyan Wang, Lei Qiu, Hongzhong Zhao, Yang SunAbstract:When inverse synthetic aperture radar (ISAR) imaging maneuvers targets, the azimuth echo of the target Scattering Point causes a Doppler frequency time-varying problem, which leads to the blurring and defocusing of the imaging results. Traditional imaging methods struggle to meet the imaging requirements for maneuvering targets due to a poor imaging effect or low efficiency. Given these challenges, a modified chirp Fourier transform (MCFT) imaging method is proposed in this paper, based on the specific relationship between the target rotation parameters and the radar echo signal parameters. Firstly, discrete chirp Fourier transform is used to quickly estimate the target’s coarse rotation ratio. Then, the minimum entropy function and gradient descent method are used to calculate the target’s accurate rotation ratio. Finally, the azimuth focusing image is accomplished by performing MCFT once on the azimuth echo signal using the accurate rotation ratio. This method avoids estimating and separating the sub-echo components one-by-one, considerably improves the imaging speed, and guarantees the best imaging quality by applying the global minimum entropy principle. The experimental results show that the proposed method effectively achieves the two-dimensional, high-quality, and fast imaging of maneuvering targets.
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an inverse synthetic aperture ladar imaging algorithm of maneuvering target based on integral cubic phase function fractional fourier transform
Electronics, 2018Co-Authors: Hongyan Wang, Lei Qiu, Jiawei Jiang, Yang SunAbstract:When imaging maneuvering targets with inverse synthetic aperture ladar (ISAL), dispersion and Doppler frequency time-variation exist in the range and cross-range echo signal, respectively. To solve this problem, an ISAL imaging algorithm based on integral cubic phase function-fractional Fourier transform (ICPF-FRFT) is proposed in this paper. The accurate ISAL echo signal model is established for a space maneuvering target that quickly approximates the uniform acceleration motion. On this basis, the chirp rate of the echo signal is quickly estimated by using the ICPF algorithm, which uses the non-uniform fast Fourier transform (NUFFT) method for fast calculations. At the best rotation angle, the range compression is realized by FRFT and the range dispersion is eliminated. After motion compensation, separation imaging of strong and weak Scattering Points is realized by using ICPF-FRFT and CLEAN technique and the azimuth defocusing problem is solved. The effectiveness of the proposed method is verified by a simulation experiment of an aircraft Scattering Point model and real data.
Fred K Gruber - One of the best experts on this subject based on the ideXlab platform.
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time reversal based noniterative exact inverse Scattering of multiply Scattering Point targets
Journal of the Acoustical Society of America, 2006Co-Authors: Edwin A Marengo, Fred K GruberAbstract:This research investigates within exact Scattering theory time‐reversal‐based approaches for the inverse Scattering in a known but rather arbitrary embedding background medium of an unknown total scatterer composed of a number of dominant subwavelength (Pointlike) Scattering centers (targets) that are located at unknown positions and have unknown Scattering strengths or reflectivities (characterizing a Scattering potential). Of particular interest is the formulation of a new inverse Scattering method (comprising both inverse support and inverse medium aspects) based on a two‐step procedure. The first step (support inversion) consists of the localization of the targets via signal subspace approaches such as time‐reversal MUSIC and a new, high‐dimensional signal subspace method that is shown to be linked to maximum likelihood estimation. The second step (nonlinear medium inversion) is a new, noniterative Scattering strength inversion formula for the reconstruction of the target Scattering strengths or refle...
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time reversal based imaging and inverse Scattering of multiply Scattering Point targets
Journal of the Acoustical Society of America, 2005Co-Authors: Anthony J Devaney, Edwin A Marengo, Fred K GruberAbstract:The treatment of time-reversal imaging of multiply Scattering Point targets developed by the present authors in Gruber et al. [“Time-reversal imaging with multiple signal classification considering multiple Scattering between the targets,” J. Acoust. Soc. Am., 115, 3042–3047 (2004)] is reformulated and extended to the estimation of the target Scattering strengths using the Foldy–Lax multiple Scattering model. It is shown that the time-reversal multiple signal classification (MUSIC) pseudospectrum computed using the background Green function as the steering vector yields accurate estimates of the target locations, even in the presence of strong multiple Scattering between the targets, and that the target Scattering strengths are readily computed from the so-determined target locations using a nonlinear iterative algorithm. The paper includes computer simulations illustrating the theory and algorithms presented in the paper.
Hongyan Wang - One of the best experts on this subject based on the ideXlab platform.
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a novel inverse synthetic aperture radar imaging method for maneuvering targets based on modified chirp fourier transform
Applied Sciences, 2018Co-Authors: Yongping Wang, Hongyan Wang, Lei Qiu, Hongzhong Zhao, Yang SunAbstract:When inverse synthetic aperture radar (ISAR) imaging maneuvers targets, the azimuth echo of the target Scattering Point causes a Doppler frequency time-varying problem, which leads to the blurring and defocusing of the imaging results. Traditional imaging methods struggle to meet the imaging requirements for maneuvering targets due to a poor imaging effect or low efficiency. Given these challenges, a modified chirp Fourier transform (MCFT) imaging method is proposed in this paper, based on the specific relationship between the target rotation parameters and the radar echo signal parameters. Firstly, discrete chirp Fourier transform is used to quickly estimate the target’s coarse rotation ratio. Then, the minimum entropy function and gradient descent method are used to calculate the target’s accurate rotation ratio. Finally, the azimuth focusing image is accomplished by performing MCFT once on the azimuth echo signal using the accurate rotation ratio. This method avoids estimating and separating the sub-echo components one-by-one, considerably improves the imaging speed, and guarantees the best imaging quality by applying the global minimum entropy principle. The experimental results show that the proposed method effectively achieves the two-dimensional, high-quality, and fast imaging of maneuvering targets.
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an inverse synthetic aperture ladar imaging algorithm of maneuvering target based on integral cubic phase function fractional fourier transform
Electronics, 2018Co-Authors: Hongyan Wang, Lei Qiu, Jiawei Jiang, Yang SunAbstract:When imaging maneuvering targets with inverse synthetic aperture ladar (ISAL), dispersion and Doppler frequency time-variation exist in the range and cross-range echo signal, respectively. To solve this problem, an ISAL imaging algorithm based on integral cubic phase function-fractional Fourier transform (ICPF-FRFT) is proposed in this paper. The accurate ISAL echo signal model is established for a space maneuvering target that quickly approximates the uniform acceleration motion. On this basis, the chirp rate of the echo signal is quickly estimated by using the ICPF algorithm, which uses the non-uniform fast Fourier transform (NUFFT) method for fast calculations. At the best rotation angle, the range compression is realized by FRFT and the range dispersion is eliminated. After motion compensation, separation imaging of strong and weak Scattering Points is realized by using ICPF-FRFT and CLEAN technique and the azimuth defocusing problem is solved. The effectiveness of the proposed method is verified by a simulation experiment of an aircraft Scattering Point model and real data.
Lei Qiu - One of the best experts on this subject based on the ideXlab platform.
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a novel inverse synthetic aperture radar imaging method for maneuvering targets based on modified chirp fourier transform
Applied Sciences, 2018Co-Authors: Yongping Wang, Hongyan Wang, Lei Qiu, Hongzhong Zhao, Yang SunAbstract:When inverse synthetic aperture radar (ISAR) imaging maneuvers targets, the azimuth echo of the target Scattering Point causes a Doppler frequency time-varying problem, which leads to the blurring and defocusing of the imaging results. Traditional imaging methods struggle to meet the imaging requirements for maneuvering targets due to a poor imaging effect or low efficiency. Given these challenges, a modified chirp Fourier transform (MCFT) imaging method is proposed in this paper, based on the specific relationship between the target rotation parameters and the radar echo signal parameters. Firstly, discrete chirp Fourier transform is used to quickly estimate the target’s coarse rotation ratio. Then, the minimum entropy function and gradient descent method are used to calculate the target’s accurate rotation ratio. Finally, the azimuth focusing image is accomplished by performing MCFT once on the azimuth echo signal using the accurate rotation ratio. This method avoids estimating and separating the sub-echo components one-by-one, considerably improves the imaging speed, and guarantees the best imaging quality by applying the global minimum entropy principle. The experimental results show that the proposed method effectively achieves the two-dimensional, high-quality, and fast imaging of maneuvering targets.
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an inverse synthetic aperture ladar imaging algorithm of maneuvering target based on integral cubic phase function fractional fourier transform
Electronics, 2018Co-Authors: Hongyan Wang, Lei Qiu, Jiawei Jiang, Yang SunAbstract:When imaging maneuvering targets with inverse synthetic aperture ladar (ISAL), dispersion and Doppler frequency time-variation exist in the range and cross-range echo signal, respectively. To solve this problem, an ISAL imaging algorithm based on integral cubic phase function-fractional Fourier transform (ICPF-FRFT) is proposed in this paper. The accurate ISAL echo signal model is established for a space maneuvering target that quickly approximates the uniform acceleration motion. On this basis, the chirp rate of the echo signal is quickly estimated by using the ICPF algorithm, which uses the non-uniform fast Fourier transform (NUFFT) method for fast calculations. At the best rotation angle, the range compression is realized by FRFT and the range dispersion is eliminated. After motion compensation, separation imaging of strong and weak Scattering Points is realized by using ICPF-FRFT and CLEAN technique and the azimuth defocusing problem is solved. The effectiveness of the proposed method is verified by a simulation experiment of an aircraft Scattering Point model and real data.
Edwin A Marengo - One of the best experts on this subject based on the ideXlab platform.
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time reversal based noniterative exact inverse Scattering of multiply Scattering Point targets
Journal of the Acoustical Society of America, 2006Co-Authors: Edwin A Marengo, Fred K GruberAbstract:This research investigates within exact Scattering theory time‐reversal‐based approaches for the inverse Scattering in a known but rather arbitrary embedding background medium of an unknown total scatterer composed of a number of dominant subwavelength (Pointlike) Scattering centers (targets) that are located at unknown positions and have unknown Scattering strengths or reflectivities (characterizing a Scattering potential). Of particular interest is the formulation of a new inverse Scattering method (comprising both inverse support and inverse medium aspects) based on a two‐step procedure. The first step (support inversion) consists of the localization of the targets via signal subspace approaches such as time‐reversal MUSIC and a new, high‐dimensional signal subspace method that is shown to be linked to maximum likelihood estimation. The second step (nonlinear medium inversion) is a new, noniterative Scattering strength inversion formula for the reconstruction of the target Scattering strengths or refle...
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time reversal based imaging and inverse Scattering of multiply Scattering Point targets
Journal of the Acoustical Society of America, 2005Co-Authors: Anthony J Devaney, Edwin A Marengo, Fred K GruberAbstract:The treatment of time-reversal imaging of multiply Scattering Point targets developed by the present authors in Gruber et al. [“Time-reversal imaging with multiple signal classification considering multiple Scattering between the targets,” J. Acoust. Soc. Am., 115, 3042–3047 (2004)] is reformulated and extended to the estimation of the target Scattering strengths using the Foldy–Lax multiple Scattering model. It is shown that the time-reversal multiple signal classification (MUSIC) pseudospectrum computed using the background Green function as the steering vector yields accurate estimates of the target locations, even in the presence of strong multiple Scattering between the targets, and that the target Scattering strengths are readily computed from the so-determined target locations using a nonlinear iterative algorithm. The paper includes computer simulations illustrating the theory and algorithms presented in the paper.
