The Experts below are selected from a list of 89709 Experts worldwide ranked by ideXlab platform

Penghui Huang - One of the best experts on this subject based on the ideXlab platform.

  • refocusing and Motion Parameter estimation for ground moving targets based on improved axis rotation time reversal transform
    IEEE Transactions on Computational Imaging, 2018
    Co-Authors: Penghui Huang, Xianggen Xia, Xingzhao Liu, Guisheng Liao
    Abstract:

    In this paper, a new algorithm is presented to image ground moving targets and estimate their Motion Parameters in a synthetic aperture radar system based on improved axis rotation-time reversal transform (IAR-TRT). In this algorithm, the second-order Keystone transform) is applied to correct the range curvature, where the Doppler ambiguity caused by a fast-moving target is considered. Then, residual linear range migration and Doppler frequency migration are eliminated by IAR-TRT, which performs an improved axis rotation transform to correct the range walk and subsequently realizes the coherent integration based on time reversal transform. Finally, a ground moving target is well focused. Additionally, the proposed method has a relatively low computational complexity since the exhaustive searching for Doppler chirp rate estimation is avoided. The effectiveness of the proposed algorithm is validated by both simulated and real data.

  • an approach for refocusing of ground moving target without target Motion Parameter estimation
    IEEE Transactions on Geoscience and Remote Sensing, 2017
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Xianggen Xia, Xuepan Zhang
    Abstract:

    In synthetic aperture radar (SAR), long integration time may induce range migration and Doppler frequency migration of a received signal, which may degrade the SAR imaging performance of ground moving targets. Most of the conventional algorithms deal with the problems of range migration and Doppler frequency migration based on Parameter searching. However, the exhaustive searching of target Motion Parameters may result in heavy computational burden. To avoid this problem, this paper proposes a new imaging method for ground moving targets without target Motion Parameter estimation. First, Keystone transform is applied to correct the range walk. Second, range curvature is compensated by the matched filtering function. Third, Doppler frequency migration is compensated via multiplying the data in range- and azimuth-time domains by its reversed conjugate data according to the equal interval sampling of the azimuth slow time, which avoids the searching procedure for target Motion Parameter estimation. Finally, the signal energy will be well accumulated in the range–Doppler domain, and thus, the moving targets can be efficiently recognized in the focused image. The major advantage of the proposed method is that it can obtain well-focused images of all targets in one processing step without target Motion Parameter estimation; thus, it is computationally efficient. Both simulated and real data processing results are used to validate the effectiveness of the proposed method.

  • ground maneuvering target imaging and high order Motion Parameter estimation based on second order keystone and generalized hough haf transform
    IEEE Transactions on Geoscience and Remote Sensing, 2017
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Xianggen Xia, Jibin Zheng
    Abstract:

    This paper proposes a new method to focus a ground moving target with complex Motions and estimate its Motion Parameters in a synthetic aperture radar (SAR) system. In this method, the second-order Keystone transform is applied to correct the range curvature. Then, the Hough transform is applied to estimate the slope of the range walk trajectory, from which the target cross-track velocity is obtained. Finally, a generalized Hough-high-order ambiguity function (GHHAF) transform is applied to transform the target signal into a 2-D time–frequency plane and estimate its slope associated with the third-order Doppler Parameter. Compared with the conventional SAR imaging methods using the second-order phase model, the proposed method can obtain better imaging quality since the third-order Doppler frequency migration is effectively eliminated. Both simulated and real data processing results are provided to validate the effectiveness of the proposed algorithm.

  • long time coherent integration for weak maneuvering target detection and high order Motion Parameter estimation based on keystone transform
    IEEE Transactions on Signal Processing, 2016
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Xianggen Xia
    Abstract:

    In the airborne or spaceborne radar applications, prolonging the coherent integration time is one of the effective methods to improve the radar detection ability of a weak maneuvering target, whereas the coherent integration performance may degrade due to the complex range migration (RM) and Doppler frequency migration (DFM) effects. In this paper, detection and Motion Parameter estimation for a weak maneuvering target with the third-order RM and DFM are considered. Firstly, Keystone transform is applied to compensate the linear range walk. Then, the matched filtering processing is performed in the range-frequency and azimuth-time domain to eliminate the residual coupling effects between range and azimuth. Finally, a well-focused image of a moving target is obtained, and three Motion Parameters, i.e., velocity, acceleration, and acceleration rate, are effectively estimated. In addition, as for a fast-moving target with Doppler ambiguity, two cases, i.e., target azimuth spectrum within a pulse repetition frequency (PRF) and spanning over neighboring PRF bands, are analyzed. Compared with the generalized Radon Fourier transform (GRFT), the proposed method can acquire a close integration performance but with lower computational complexity since the Parameter searching dimension is reduced. Simulated processing results are provided to validate the effectiveness of the proposed method.

  • an approach for refocusing of ground fast moving target and high order Motion Parameter estimation using radon high order time chirp rate transform
    Digital Signal Processing, 2016
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang
    Abstract:

    Long synthetic aperture time can improve the imaging quality of a ground moving target, whereas a moving target may be severely smeared in the cross-range image due to the range migration and the Doppler frequency migration. In this paper, the effects of the third-order Doppler broadening and Doppler ambiguity of a fast-moving target are considered. To address these issues, a novel Motion Parameter estimation method named high-order time-chirp rate transform (HTRT) is proposed, and then a new synthetic aperture radar (SAR) imaging method based on Radon-HTRT (RHTRT) for a ground moving target is developed. The major contributions are as follows: 1) The proposed SAR imaging method can eliminate the Doppler ambiguity effect. 2) The proposed method can realize longer time coherent integration than Radon-Fourier transform (RFT) and Radon-fractional Fourier transform (RFRFT) methods. 3) The proposed method is computationally efficient since HTRT can obtain the Motion Parameters of a moving target via performing the 2-dimensional (2-D) fast Fourier transform (FFT). Both the simulated and real data processing results show that the proposed method can finely image a ground moving target in a high signal-to-clutter and noise ratio (SCNR) environment.

Guisheng Liao - One of the best experts on this subject based on the ideXlab platform.

  • refocusing and Motion Parameter estimation for ground moving targets based on improved axis rotation time reversal transform
    IEEE Transactions on Computational Imaging, 2018
    Co-Authors: Penghui Huang, Xianggen Xia, Xingzhao Liu, Guisheng Liao
    Abstract:

    In this paper, a new algorithm is presented to image ground moving targets and estimate their Motion Parameters in a synthetic aperture radar system based on improved axis rotation-time reversal transform (IAR-TRT). In this algorithm, the second-order Keystone transform) is applied to correct the range curvature, where the Doppler ambiguity caused by a fast-moving target is considered. Then, residual linear range migration and Doppler frequency migration are eliminated by IAR-TRT, which performs an improved axis rotation transform to correct the range walk and subsequently realizes the coherent integration based on time reversal transform. Finally, a ground moving target is well focused. Additionally, the proposed method has a relatively low computational complexity since the exhaustive searching for Doppler chirp rate estimation is avoided. The effectiveness of the proposed algorithm is validated by both simulated and real data.

  • an approach for refocusing of ground moving target without target Motion Parameter estimation
    IEEE Transactions on Geoscience and Remote Sensing, 2017
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Xianggen Xia, Xuepan Zhang
    Abstract:

    In synthetic aperture radar (SAR), long integration time may induce range migration and Doppler frequency migration of a received signal, which may degrade the SAR imaging performance of ground moving targets. Most of the conventional algorithms deal with the problems of range migration and Doppler frequency migration based on Parameter searching. However, the exhaustive searching of target Motion Parameters may result in heavy computational burden. To avoid this problem, this paper proposes a new imaging method for ground moving targets without target Motion Parameter estimation. First, Keystone transform is applied to correct the range walk. Second, range curvature is compensated by the matched filtering function. Third, Doppler frequency migration is compensated via multiplying the data in range- and azimuth-time domains by its reversed conjugate data according to the equal interval sampling of the azimuth slow time, which avoids the searching procedure for target Motion Parameter estimation. Finally, the signal energy will be well accumulated in the range–Doppler domain, and thus, the moving targets can be efficiently recognized in the focused image. The major advantage of the proposed method is that it can obtain well-focused images of all targets in one processing step without target Motion Parameter estimation; thus, it is computationally efficient. Both simulated and real data processing results are used to validate the effectiveness of the proposed method.

  • ground maneuvering target imaging and high order Motion Parameter estimation based on second order keystone and generalized hough haf transform
    IEEE Transactions on Geoscience and Remote Sensing, 2017
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Xianggen Xia, Jibin Zheng
    Abstract:

    This paper proposes a new method to focus a ground moving target with complex Motions and estimate its Motion Parameters in a synthetic aperture radar (SAR) system. In this method, the second-order Keystone transform is applied to correct the range curvature. Then, the Hough transform is applied to estimate the slope of the range walk trajectory, from which the target cross-track velocity is obtained. Finally, a generalized Hough-high-order ambiguity function (GHHAF) transform is applied to transform the target signal into a 2-D time–frequency plane and estimate its slope associated with the third-order Doppler Parameter. Compared with the conventional SAR imaging methods using the second-order phase model, the proposed method can obtain better imaging quality since the third-order Doppler frequency migration is effectively eliminated. Both simulated and real data processing results are provided to validate the effectiveness of the proposed algorithm.

  • long time coherent integration for weak maneuvering target detection and high order Motion Parameter estimation based on keystone transform
    IEEE Transactions on Signal Processing, 2016
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Xianggen Xia
    Abstract:

    In the airborne or spaceborne radar applications, prolonging the coherent integration time is one of the effective methods to improve the radar detection ability of a weak maneuvering target, whereas the coherent integration performance may degrade due to the complex range migration (RM) and Doppler frequency migration (DFM) effects. In this paper, detection and Motion Parameter estimation for a weak maneuvering target with the third-order RM and DFM are considered. Firstly, Keystone transform is applied to compensate the linear range walk. Then, the matched filtering processing is performed in the range-frequency and azimuth-time domain to eliminate the residual coupling effects between range and azimuth. Finally, a well-focused image of a moving target is obtained, and three Motion Parameters, i.e., velocity, acceleration, and acceleration rate, are effectively estimated. In addition, as for a fast-moving target with Doppler ambiguity, two cases, i.e., target azimuth spectrum within a pulse repetition frequency (PRF) and spanning over neighboring PRF bands, are analyzed. Compared with the generalized Radon Fourier transform (GRFT), the proposed method can acquire a close integration performance but with lower computational complexity since the Parameter searching dimension is reduced. Simulated processing results are provided to validate the effectiveness of the proposed method.

  • an approach for refocusing of ground fast moving target and high order Motion Parameter estimation using radon high order time chirp rate transform
    Digital Signal Processing, 2016
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang
    Abstract:

    Long synthetic aperture time can improve the imaging quality of a ground moving target, whereas a moving target may be severely smeared in the cross-range image due to the range migration and the Doppler frequency migration. In this paper, the effects of the third-order Doppler broadening and Doppler ambiguity of a fast-moving target are considered. To address these issues, a novel Motion Parameter estimation method named high-order time-chirp rate transform (HTRT) is proposed, and then a new synthetic aperture radar (SAR) imaging method based on Radon-HTRT (RHTRT) for a ground moving target is developed. The major contributions are as follows: 1) The proposed SAR imaging method can eliminate the Doppler ambiguity effect. 2) The proposed method can realize longer time coherent integration than Radon-Fourier transform (RFT) and Radon-fractional Fourier transform (RFRFT) methods. 3) The proposed method is computationally efficient since HTRT can obtain the Motion Parameters of a moving target via performing the 2-dimensional (2-D) fast Fourier transform (FFT). Both the simulated and real data processing results show that the proposed method can finely image a ground moving target in a high signal-to-clutter and noise ratio (SCNR) environment.

Xianggen Xia - One of the best experts on this subject based on the ideXlab platform.

  • refocusing and Motion Parameter estimation for ground moving targets based on improved axis rotation time reversal transform
    IEEE Transactions on Computational Imaging, 2018
    Co-Authors: Penghui Huang, Xianggen Xia, Xingzhao Liu, Guisheng Liao
    Abstract:

    In this paper, a new algorithm is presented to image ground moving targets and estimate their Motion Parameters in a synthetic aperture radar system based on improved axis rotation-time reversal transform (IAR-TRT). In this algorithm, the second-order Keystone transform) is applied to correct the range curvature, where the Doppler ambiguity caused by a fast-moving target is considered. Then, residual linear range migration and Doppler frequency migration are eliminated by IAR-TRT, which performs an improved axis rotation transform to correct the range walk and subsequently realizes the coherent integration based on time reversal transform. Finally, a ground moving target is well focused. Additionally, the proposed method has a relatively low computational complexity since the exhaustive searching for Doppler chirp rate estimation is avoided. The effectiveness of the proposed algorithm is validated by both simulated and real data.

  • an approach for refocusing of ground moving target without target Motion Parameter estimation
    IEEE Transactions on Geoscience and Remote Sensing, 2017
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Xianggen Xia, Xuepan Zhang
    Abstract:

    In synthetic aperture radar (SAR), long integration time may induce range migration and Doppler frequency migration of a received signal, which may degrade the SAR imaging performance of ground moving targets. Most of the conventional algorithms deal with the problems of range migration and Doppler frequency migration based on Parameter searching. However, the exhaustive searching of target Motion Parameters may result in heavy computational burden. To avoid this problem, this paper proposes a new imaging method for ground moving targets without target Motion Parameter estimation. First, Keystone transform is applied to correct the range walk. Second, range curvature is compensated by the matched filtering function. Third, Doppler frequency migration is compensated via multiplying the data in range- and azimuth-time domains by its reversed conjugate data according to the equal interval sampling of the azimuth slow time, which avoids the searching procedure for target Motion Parameter estimation. Finally, the signal energy will be well accumulated in the range–Doppler domain, and thus, the moving targets can be efficiently recognized in the focused image. The major advantage of the proposed method is that it can obtain well-focused images of all targets in one processing step without target Motion Parameter estimation; thus, it is computationally efficient. Both simulated and real data processing results are used to validate the effectiveness of the proposed method.

  • ground maneuvering target imaging and high order Motion Parameter estimation based on second order keystone and generalized hough haf transform
    IEEE Transactions on Geoscience and Remote Sensing, 2017
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Xianggen Xia, Jibin Zheng
    Abstract:

    This paper proposes a new method to focus a ground moving target with complex Motions and estimate its Motion Parameters in a synthetic aperture radar (SAR) system. In this method, the second-order Keystone transform is applied to correct the range curvature. Then, the Hough transform is applied to estimate the slope of the range walk trajectory, from which the target cross-track velocity is obtained. Finally, a generalized Hough-high-order ambiguity function (GHHAF) transform is applied to transform the target signal into a 2-D time–frequency plane and estimate its slope associated with the third-order Doppler Parameter. Compared with the conventional SAR imaging methods using the second-order phase model, the proposed method can obtain better imaging quality since the third-order Doppler frequency migration is effectively eliminated. Both simulated and real data processing results are provided to validate the effectiveness of the proposed algorithm.

  • a new Motion Parameter estimation algorithm based on sdfc lvt
    IEEE Transactions on Aerospace and Electronic Systems, 2016
    Co-Authors: Jing Tian, Wei Cui, Xianggen Xia
    Abstract:

    This paper proposes a new Motion Parameter estimation algorithm, namely subband dual-frequency conjugate-Lv’s transform, for fast moving targets. This algorithm first constructs two subband signals with different central frequencies. Then, the two signals are shifted by different values and a new signal is constructed by multiplying one with the complex conjugate of the other. Finally, Keystone transform and LVT are performed to obtain the estimates. This method does not need any prior-knowledge of targets and can resolve the Doppler ambiguity problem when Keystone transform does not work, especially when the ambiguity number splits into two numbers. Both simulated and real data demonstrate the effectiveness of the proposed algorithm.

  • long time coherent integration for weak maneuvering target detection and high order Motion Parameter estimation based on keystone transform
    IEEE Transactions on Signal Processing, 2016
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Xianggen Xia
    Abstract:

    In the airborne or spaceborne radar applications, prolonging the coherent integration time is one of the effective methods to improve the radar detection ability of a weak maneuvering target, whereas the coherent integration performance may degrade due to the complex range migration (RM) and Doppler frequency migration (DFM) effects. In this paper, detection and Motion Parameter estimation for a weak maneuvering target with the third-order RM and DFM are considered. Firstly, Keystone transform is applied to compensate the linear range walk. Then, the matched filtering processing is performed in the range-frequency and azimuth-time domain to eliminate the residual coupling effects between range and azimuth. Finally, a well-focused image of a moving target is obtained, and three Motion Parameters, i.e., velocity, acceleration, and acceleration rate, are effectively estimated. In addition, as for a fast-moving target with Doppler ambiguity, two cases, i.e., target azimuth spectrum within a pulse repetition frequency (PRF) and spanning over neighboring PRF bands, are analyzed. Compared with the generalized Radon Fourier transform (GRFT), the proposed method can acquire a close integration performance but with lower computational complexity since the Parameter searching dimension is reduced. Simulated processing results are provided to validate the effectiveness of the proposed method.

Anuar Mohd Ishak - One of the best experts on this subject based on the ideXlab platform.

  • unsteady boundary layer flow of a nanofluid over a stretching shrinking sheet with a convective boundary condition
    Journal of the Egyptian Mathematical Society, 2016
    Co-Authors: Syahira Mansur, Anuar Mohd Ishak
    Abstract:

    Abstract The unsteady boundary layer flow of a nanofluid past a stretching/shrinking sheet with a convective surface boundary condition is studied. The effects of the unsteadiness Parameter, stretching/shrinking Parameter, convective Parameter, Brownian Motion Parameter and thermophoresis Parameter on the local Nusselt number are investigated. Numerical solutions to the governing equations are obtained using a shooting method. The results for the local Nusselt number are presented for different values of the governing Parameters. The local Nusselt number decreases as the stretching/shrinking Parameter increases. The local Nusselt number is consistently higher for higher values of the convective Parameter but lower for higher values of the unsteadiness Parameter, Brownian Motion Parameter and thermophoresis Parameter.

  • the magnetohydrodynamic stagnation point flow of a nanofluid over a stretching shrinking sheet with suction
    PLOS ONE, 2015
    Co-Authors: Syahira Mansur, Anuar Mohd Ishak, Ioan Pop
    Abstract:

    The magnetohydrodynamic (MHD) stagnation point flow of a nanofluid over a permeable stretching/shrinking sheet is studied. Numerical results are obtained using boundary value problem solver bvp4c in MATLAB for several values of Parameters. The numerical results show that dual solutions exist for the shrinking case, while for the stretching case, the solution is unique. A stability analysis is performed to determine the stability of the dual solutions. For the stable solution, the skin friction is higher in the presence of magnetic field and increases when the suction effect is increased. It is also found that increasing the Brownian Motion Parameter and the thermophoresis Parameter reduces the heat transfer rate at the surface.

  • boundary layer flow of nanofluids over a moving surface in a flowing fluid
    International Journal of Thermal Sciences, 2010
    Co-Authors: Norfifah Bachok, Anuar Mohd Ishak
    Abstract:

    The steady boundary-layer flow of a nanofluid past a moving semi-infinite flat plate in a uniform free stream is investigated. The plate is assumed to move in the same or opposite directions to the free stream. The resulting system of nonlinear ordinary differential equations is solved numerically using the Keller-box method. Numerical results are obtained for the skin-friction coefficient, the local Nusselt number and the local Sherwood number as well as the velocity, temperature and the nanoparticle volume fraction profiles for some values of the governing Parameters, namely, the plate velocity Parameter, Prandtl number, Lewis number, the Brownian Motion Parameter and the thermophoresis Parameter. The results indicate that dual solutions exist when the plate and the free stream move in the opposite directions.

Zhiwei Yang - One of the best experts on this subject based on the ideXlab platform.

  • an approach for refocusing of ground moving target without target Motion Parameter estimation
    IEEE Transactions on Geoscience and Remote Sensing, 2017
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Xianggen Xia, Xuepan Zhang
    Abstract:

    In synthetic aperture radar (SAR), long integration time may induce range migration and Doppler frequency migration of a received signal, which may degrade the SAR imaging performance of ground moving targets. Most of the conventional algorithms deal with the problems of range migration and Doppler frequency migration based on Parameter searching. However, the exhaustive searching of target Motion Parameters may result in heavy computational burden. To avoid this problem, this paper proposes a new imaging method for ground moving targets without target Motion Parameter estimation. First, Keystone transform is applied to correct the range walk. Second, range curvature is compensated by the matched filtering function. Third, Doppler frequency migration is compensated via multiplying the data in range- and azimuth-time domains by its reversed conjugate data according to the equal interval sampling of the azimuth slow time, which avoids the searching procedure for target Motion Parameter estimation. Finally, the signal energy will be well accumulated in the range–Doppler domain, and thus, the moving targets can be efficiently recognized in the focused image. The major advantage of the proposed method is that it can obtain well-focused images of all targets in one processing step without target Motion Parameter estimation; thus, it is computationally efficient. Both simulated and real data processing results are used to validate the effectiveness of the proposed method.

  • ground maneuvering target imaging and high order Motion Parameter estimation based on second order keystone and generalized hough haf transform
    IEEE Transactions on Geoscience and Remote Sensing, 2017
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Xianggen Xia, Jibin Zheng
    Abstract:

    This paper proposes a new method to focus a ground moving target with complex Motions and estimate its Motion Parameters in a synthetic aperture radar (SAR) system. In this method, the second-order Keystone transform is applied to correct the range curvature. Then, the Hough transform is applied to estimate the slope of the range walk trajectory, from which the target cross-track velocity is obtained. Finally, a generalized Hough-high-order ambiguity function (GHHAF) transform is applied to transform the target signal into a 2-D time–frequency plane and estimate its slope associated with the third-order Doppler Parameter. Compared with the conventional SAR imaging methods using the second-order phase model, the proposed method can obtain better imaging quality since the third-order Doppler frequency migration is effectively eliminated. Both simulated and real data processing results are provided to validate the effectiveness of the proposed algorithm.

  • long time coherent integration for weak maneuvering target detection and high order Motion Parameter estimation based on keystone transform
    IEEE Transactions on Signal Processing, 2016
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Xianggen Xia
    Abstract:

    In the airborne or spaceborne radar applications, prolonging the coherent integration time is one of the effective methods to improve the radar detection ability of a weak maneuvering target, whereas the coherent integration performance may degrade due to the complex range migration (RM) and Doppler frequency migration (DFM) effects. In this paper, detection and Motion Parameter estimation for a weak maneuvering target with the third-order RM and DFM are considered. Firstly, Keystone transform is applied to compensate the linear range walk. Then, the matched filtering processing is performed in the range-frequency and azimuth-time domain to eliminate the residual coupling effects between range and azimuth. Finally, a well-focused image of a moving target is obtained, and three Motion Parameters, i.e., velocity, acceleration, and acceleration rate, are effectively estimated. In addition, as for a fast-moving target with Doppler ambiguity, two cases, i.e., target azimuth spectrum within a pulse repetition frequency (PRF) and spanning over neighboring PRF bands, are analyzed. Compared with the generalized Radon Fourier transform (GRFT), the proposed method can acquire a close integration performance but with lower computational complexity since the Parameter searching dimension is reduced. Simulated processing results are provided to validate the effectiveness of the proposed method.

  • an approach for refocusing of ground fast moving target and high order Motion Parameter estimation using radon high order time chirp rate transform
    Digital Signal Processing, 2016
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang
    Abstract:

    Long synthetic aperture time can improve the imaging quality of a ground moving target, whereas a moving target may be severely smeared in the cross-range image due to the range migration and the Doppler frequency migration. In this paper, the effects of the third-order Doppler broadening and Doppler ambiguity of a fast-moving target are considered. To address these issues, a novel Motion Parameter estimation method named high-order time-chirp rate transform (HTRT) is proposed, and then a new synthetic aperture radar (SAR) imaging method based on Radon-HTRT (RHTRT) for a ground moving target is developed. The major contributions are as follows: 1) The proposed SAR imaging method can eliminate the Doppler ambiguity effect. 2) The proposed method can realize longer time coherent integration than Radon-Fourier transform (RFT) and Radon-fractional Fourier transform (RFRFT) methods. 3) The proposed method is computationally efficient since HTRT can obtain the Motion Parameters of a moving target via performing the 2-dimensional (2-D) fast Fourier transform (FFT). Both the simulated and real data processing results show that the proposed method can finely image a ground moving target in a high signal-to-clutter and noise ratio (SCNR) environment.

  • approach for space based radar manoeuvring target detection and high order Motion Parameter estimation
    Iet Radar Sonar and Navigation, 2015
    Co-Authors: Penghui Huang, Guisheng Liao, Zhiwei Yang, Yuxiang Shu
    Abstract:

    The detection of manoeuvring target for space-based radar is a challenging task because of its weak energy and manoeuvring Motion. Prolonging the integration time is an effective method to increase signal energy, which can improve the target detection performance. However, with the increase of integration time, the radial velocity, radial acceleration and radial acceleration rate of manoeuvring target will induce linear range walk, quadratic-range curvature, cubic-range curvature and Doppler frequency migration of echo signal, which may degrade the performance of target detection. To solve this problem, a novel method is proposed that implements a Parameter separation transform to isolate the acceleration. Then, the velocity and the acceleration rate can be obtained via one-dimensional search after the compensation of linear and cubic-range migration based on Hough transform and third-order Keystone transform. The kernel steps are as follows: (i) the acceleration is isolated by multiplying the range-compressed data in range frequency domain by its time-reversed data according to the symmetrical property of azimuth slow time; (ii) the cubic-range curvature is corrected by a third-order Keystone transform. The simulation results demonstrate the effectiveness of the proposed method in estimating radial velocity, radial acceleration and radial acceleration rate of a manoeuvring target, thereby the signal energy can be finely accumulated.