volume | PIER Journals

Abstract

The difficulty of focusing high-resolution highly squinted SAR data comes from the serious azimuth-range coupling, which needs to be compensated in the procedure of imaging. Generally, the linear range walk correction (LRWC) can reduce the coupling effectively, however, it also induces the problem of azimuth-dependence of residual range cell migration (RCM) and quadratic phase. A novel algorithm is proposed to solve this problem in this paper. In this algorithm, the azimuth nonlinear chirp scaling (ANCS) operation is used, which can not only eliminate the azimuth space variation of residual RCM and frequency modulation (FM) rate but also remove the azimuth misregistration. In addition, the range chirp scaling operation is applied to correct the range-dependent RCM. After implementing the unified RCM correction, range compression and azimuth compression sequentially, the focused SAR image is acquired finally. The experimental results with simulated data demonstrate that the proposed algorithm outperforms the existing algorithms.

1. Chan, Y. K. and V. C. Koo, "An introduction to synthetic aperture radar (SAR)," Progress In Electromagnetics Research B, Vol. 2, 27-60, 2008.
doi:10.2528/PIERB07110101

2. Xu, W., P. P. Huang, and Y.-K. Deng, "Multi-channel SPCMB-tops SAR for high-resolution wide-swath imaging," Progress In Electromagnetics Research, Vol. 116, 533-551, 2011.

3. Park, S.-H., J.-I. Park, and K.-T. Kim, "Motion compensation for squint mode spotlight SAR imaging using effcient 2D interpolation," Progress In Electromagnetics Research, Vol. 128, 503-518, 2012.

4. Davidson, G. W., I. G. Cumming, and M. R. Ito, "A chirp scaling approach for processing squint mode SAR data," IEEE Trans. Aerosp. Electron. Syst., Vol. 32, No. 1, 121-133, Jan. 1996.
doi:10.1109/7.481254

5. Yeo, T. S., N. L. Tan, C. Zhang, and Y. Lu, "A new subaperture approach to high squint SAR processing," IEEE Trans. Geosci. Remote Sens., Vol. 39, No. 5, 954-968, May 2001.
doi:10.1109/36.921413

6. Soumekh, M., "Synthetic Aperture Radar Signal Processing with MATLAB Algorithms," Wiley, 1999.

7. Smith, A. M., "A new approach to range-Doppler SAR processing," Int. J. Remote Sens., Vol. 12, No. 2, 235-251, 1991.
doi:10.1080/01431169108929650

8. Chen, J., J. Gao, Y. Zhu, W. Yang, and P. Wang, "A novel image formation algorithm for high-resolution wide-swath spaceborne SAR using compressed sensing on azimuth displacement phase center antenna," Progress In Electromagnetics Research, Vol. 125, 527-543, 2012.
doi:10.2528/PIER11121101

9. Moreira, A. and Y.H. Huang, "Airborne SAR processing of highly squinted data using a chirp scaling approach with integrated motion compensation," IEEE Trans. Geosci. Remote Sens., Vol. 32, No. 5, 1029-1040, Sep. 1994.
doi:10.1109/36.312891

10. Moreira, A., J. Mittermayer, and R. Scheiber, "Extended chirp scaling algorithm for air- and spaceborne SAR data processing in stripmap and ScanSAR imaging modes," IEEE Trans. Geosci. Remote Sens., Vol. 34, No. 5, 1123-1136, Sep. 1996.
doi:10.1109/36.536528

11. Cumming, I. G. and F. H. Wong, Digital Processing of Synthetic Aperture Radar Data, Artech House, 2005.

12. Reigber, A., E. Alivizatos, A. Potsis, and A. Moreira, "Extended wavenumber-domain synthetic aperture radar focusing with integrated motion compensation," Proc. Inst. Elect. Eng. --- Radar Sonar Navig., Vol. 153, No. 3, 301-310, Jun. 2006.
doi:10.1049/ip-rsn:20045087

13. Wong, F. H. and T. S. Yeo, "New applications of nonlinear chirp scaling in SAR data processing," IEEE Trans. Geosci. Remote Sens., Vol. 39, No. 5, 946-953, May 2001.
doi:10.1109/36.921412

14. Sun, G. C., X. W. Jiang, M. D. Xing, Z. J. Qiao, Y. R. Wu, and Z. Bao, "Focus improvement of highly squinted data based on azimuth nonlinear scaling," IEEE Trans. Geosci. Remote Sens., Vol. 49, No. 6, 2308-2322, Jun. 2011.
doi:10.1109/TGRS.2010.2102040

15. An, D. X., X. T. Huang, T. Jin, and Z. M. Zhou, "Extended nonlinear chirp scaling algorithm for high-resolution highly squint SAR data focusing," IEEE Trans. Geosci. Remote Sens., Vol. 50, No. 9, 3595-3609, Sep. 2012.
doi:10.1109/TGRS.2012.2183606

16. Zhang, S. X., M. D. Xing, X. G. Xia, L. Zhang, R. Guo, and Z. Bao, IEEE Trans. Geosci. Remote Sens., Vol. 10, No. 1, 150-154, Jan. 2013.
doi:10.1109/LGRS.2012.2195634

17. An, D. X., Z.-M. Zhou, X.-T. Huang, and T. Jin, "A novel imaging approach for high resolution squinted spotlight SAR based on the deramping-based technique and azimuth NLCS principle," Progress In Electromagnetics Research, Vol. 123, 485-508, 2012.
doi:10.2528/PIER11112110

18. Chang, Y.-L., C.-Y. Chiang, and K.-S. Chen, "SAR image simulation with application to target recognition," Progress In Electromagnetics Research, Vol. 119, 35-57, 2011.
doi:10.2528/PIER11061507

19. Huang, Y. and Z. Bao, "A new two-dimension-separated approach to high squint SAR processing," J. Electron. Inf. Technol., Vol. 27, No. 1, 1-5, Jan. 2005.

Dr. Qinglin Zhai

Dr. Wei Wang

Dr. Jiemin Hu

Dr. Jun Zhang