Highly squinted SAR imaging simulation of ship-ocean scene based on EM scattering mechanism

To investigate highly squinted spotlight synthetic aperture radar (SAR) images of an electrically large ship target over a rough sea surface, this work focuses on the simulation analysis of SAR images from such a composite scene. For this problem, there are two key issues need to be considered, namely the simulation and the processing of SAR echoes. Considering the first issue, an efficient facet scattering model based on capillary wave modification facet scattering model and geometrical optics and physical optics hybrid method is applied to calculate the electromagnetic (EM) scattering characteristics from a real ship-ocean scene, based on which SAR echoes can be obtained. For the second issue, a non-linear frequency scaling algorithm (NFSA) is employed to efficiently process the highly squinted SAR echoes. Compared with the traditional frequency scaling algorithm, the NFSA extends the frequency scaling operation to the cubic order and makes a more accurate secondary range compression. With the solutions to the two issues, SAR images of a complicated ship-ocean scene under different incident and squint angles are presented and analysed. The reasonable results demonstrate the validity of the simulation approach and the practicability of the model for highly squinted spotlight SAR images.

[1]  Changqing Gu,et al.  Direct solution of electromagnetic scattering from perfect electric conducting targets using multilevel characteristic basis function method with adaptive cross approximation algorithm , 2013 .

[2]  C. Ozdemir,et al.  pRediCS: A new GO-PO-based ray launching simulator for the calculation of electromagnetic scattering and RCS from electrically large and complex structures , 2014 .

[3]  William B. Gordon,et al.  Far-field approximations to the Kirchoff-Helmholtz representations of scattered fields , 1975 .

[4]  Yi Liang,et al.  A Novel Motion Compensation Approach for Airborne Spotlight SAR of High-Resolution and High-Squint Mode , 2016, IEEE Geoscience and Remote Sensing Letters.

[5]  D. Holliday,et al.  Volterra approximation for low grazing angle shadowing on smooth ocean-like surfaces , 1995 .

[6]  Zhang Yan,et al.  Focusing Highly Squinted Data Using the Extended Nonlinear Chirp Scaling Algorithm , 2013, IEEE Geoscience and Remote Sensing Letters.

[7]  N. N. Youssef.  Radar cross section of complex targets , 1989, Proc. IEEE.

[8]  Alberto Moreira,et al.  Spotlight SAR data processing using the frequency scaling algorithm , 1999, IEEE Trans. Geosci. Remote. Sens..

[9]  Yong-Jun Xie,et al.  High-frequency method for scattering from coated targets with electrically large size in half space , 2009 .

[10]  Rushan Chen,et al.  Improved multilevel physical optics algorithm for fast computation of monostatic radar cross section , 2014 .

[11]  Daiyin Zhu,et al.  Some Aspects of Improving the Frequency Scaling Algorithm for Dechirped SAR Data Processing , 2008, IEEE Transactions on Geoscience and Remote Sensing.

[12]  L. Landesa,et al.  The generalized forward-backward method for analyzing the scattering from targets on ocean-like rough surfaces , 1999, IEEE Antennas and Propagation Society International Symposium. 1999 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.99CH37010).

[13]  R. Keith Raney,et al.  Precision SAR processing using chirp scaling , 1994, IEEE Trans. Geosci. Remote. Sens..

[14]  Qun Zhang,et al.  Imaging method for highly squinted synthetic aperture radar with under-sampled echo data , 2015 .

[15]  Daoxiang An,et al.  Extended Nonlinear Chirp Scaling Algorithm for High-Resolution Highly Squint SAR Data Focusing , 2012, IEEE Transactions on Geoscience and Remote Sensing.

[16]  Yi Liang,et al.  Focusing of Highly Squinted SAR Data With Frequency Nonlinear Chirp Scaling , 2016, IEEE Geoscience and Remote Sensing Letters.

[17]  Z.-H. Jiang,et al.  Improved nonlinear frequency scaling algorithm for squint FMCW SAR , 2007 .

[18]  Yaqiu Jin,et al.  Bidirectional Analytic Ray Tracing for Fast Computation of Composite Scattering From Electric-Large Target Over a Randomly Rough Surface , 2009, IEEE Transactions on Antennas and Propagation.

[19]  Axel Sawitzki.  Electromagnetic modelling of surfaces using method of moments with calculated phase mesh , 2015 .

[20]  Raj Mittra,et al.  Numerically efficient method-of-moments formulation valid over a wide frequency band including very low frequencies , 2012 .

[21]  Yan Wang,et al.  Geometrical distortion correction for extremely high-squint parameter-adjusting synthetic aperture radar , 2017 .

[22]  Allen Taflove,et al.  Numerical analysis of electromagnetic scattering by electrically large objects using spatial decomposition technique , 1992 .

[23]  Wei Niu,et al.  GPU-Based Combination of GO and PO for Electromagnetic Scattering of Satellite , 2012, IEEE Transactions on Antennas and Propagation.

[24]  Mengdao Xing,et al.  Focus Improvement of Highly Squinted Data Based on Azimuth Nonlinear Scaling , 2011, IEEE Transactions on Geoscience and Remote Sensing.

[25]  X. Sheng,et al.  Highly efficient hybrid method for monostatic scattering by objects on a rough surface , 2010 .

[26]  Yanfei Wang,et al.  Extended nonlinear chirp scaling algorithm for highly squinted missile-borne synthetic aperture radar with diving acceleration , 2016 .

[27]  Joel T. Johnson.  A numerical study of scattering from an object above a rough surface , 2002 .

[28]  Weifeng Sun,et al.  Efficient imaging approach for spaceborne sliding spotlight synthetic aperture radar with a small squint angle , 2015 .

[29]  Min Zhang,et al.  Reliable Approach for Composite Scattering Calculation From Ship Over a Sea Surface Based on FBAM and GO-PO Models , 2017, IEEE Transactions on Antennas and Propagation.

[30]  Hui Chen,et al.  Facet-Based Investigation on EM Scattering From Electrically Large Sea Surface With Two-Scale Profiles: Theoretical Model , 2011, IEEE Transactions on Geoscience and Remote Sensing.