volume | PIER Journals

Abstract

The novel multibeam ScanSAR takes advantage of the displaced phase center multiple azimuth beam (DPCMAB) imaging scheme and intra-pulse beam steering in elevation in ScanSAR to achieve the high-resolution ultra-wide-swath imaging capacity. This letter proposes an innovative two-dimensional (2D) digital beamforming (DBF) space-time preprocessing approach for multibeam ScanSAR. According to echo proprieties of such imaging scheme, both azimuth ambiguity and range ambiguity problems should be resolve before a conventional ScanSAR imaging processor. After range compressing in each receive channel, a 2D DBF processor is carried out in the range-Doppler domain. The azimuth DBF operation is adopted to resolve the azimuth nonuniform sampling problem in multichannel SAR systems, while the DBF preprocessing in elevation is carried out to separate echoes from different subswaths corresponding to different sub-pulses. Imaging results on simulated distributed targets validate the proposed 2D DBF preprocessing approach.

1. Curlander, J. C. and R. N. McDonough, Synthetic Aperture Radar: Systems and Signal Processing, John Wiley & Sons, New York, 1991.

2. Franceschetti, G. and R. Lanari, Synthetic Aperture Radar Processing, CRC Press, New York, 1999.

3. Guo, D., H. Xu, and J. Li, "Extended wavenumber domain algorithm for highly squinted sliding spotlight SAR data processing," Progress In Electromagnetics Research, Vol. 114, 17-32, 2011.

4. 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

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

6. Moore, R. K., J. P. Claassen, and Y. H. Lin, "Scanning spaceborne synthetic aperture radar with integrated radiometer," IEEE Trans. Aerosp. Electron. Syst., Vol. 17, No. 3, 410-420, May 1981.
doi:10.1109/TAES.1981.309069

7. Monti Guarnieri, A. and C. Prati, "ScanSAR focussing and interferometry," IEEE Trans. Geosci. Remote Sens., Vol. 34, No. 4, 1029-1038, Jul. 1996.
doi:10.1109/36.508420

8. De Zan, F. and A. Monti Guarnieri, "TOPSAR: Terrain observation by progressive scans," IEEE Trans. Geosci. Remote Sens., Vol. 44, No. 9, 2352-2360, Sep. 2006.
doi:10.1109/TGRS.2006.873853

9. Meta, A., J. Mittermayer, P. Prats, R. Scheiber, and U. Steinbrecher, "TOPS imaging with TerraSAR-X: Mode design and performance analysis," IEEE Trans. Geosci. Remote Sens., Vol. 48, No. 2, 759-769, Feb. 2010.
doi:10.1109/TGRS.2009.2026743

10. Xu, W., P. Huang, Y. Deng, J. Sun, and X. Shang, "An efficient approach with scaling factors for TOPS mode SAR data focusing," IEEE Geosci. Remote. Sens. Lett., Vol. 8, No. 5, 929-933, Sep. 2011.
doi:10.1109/LGRS.2011.2135837

11. Currie, A. and M. A. Brown, "Wide-swath SAR," Proc. Inst. Electr. Eng. F --- Radar Signal Process., Vol. 139, No. 2, 122-135, Apr. 1992.
doi:10.1049/ip-f-2.1992.0016

12. Gebert, N., G. Krieger, and A. Moreira, "Multi-channel ScanSAR for high-resolution ultra-wide-swath imaging," Proc. EUSAR, Friedrichshafen, Germany, 2008.

13. Gebert, N., G. Krieger, M. Younis, F. Bordoni, and A. Moreira, "Ultra wide swath imaging with multi-channel ScanSAR," Proc. IEEE IGARSS, 21-24, Boston, MA, Jul. 2008.

14. Gebert, N., G. Krieger, and A. Moreira, "Multichannel azimuth processing in ScanSAR and TOPS mode operation," IEEE Trans. Geosci. Remote Sens., Vol. 48, No. 7, 564-592, Jul. 2010.
doi:10.2528/PIER11121101

15. 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/PIER12021307

16. Li, J., S. Zhang, and J. Chang, "Applications of compressed sensing for multiple transmitters multiple azimuth beams SAR imaging," Progress In Electromagnetics Research, Vol. 127, 259-275, 2012.
doi:10.2528/PIER11030209

17. Xu, W., P. P. Huang, and Y.-K. Deng, "MIMO-tops mode for high-resolution ultra-wide-swath full polarimetric imaging," Progress In Electromagnetics Research, Vol. 121, 19-37, 2011.
doi:10.2528/PIER11030209

18. Xu, W., 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.
doi:10.1109/TGRS.2007.905974

19. Krieger, G., N. Gebert, and A. Moreira, "Multidimensional waveform encoding: A new digital beamforming technique for synthetic aperture radar remote sensing," IEEE Trans. Geosci. Remote Sens., Vol. 46, No. 1, 31-46, Jan. 2008.
doi:10.1109/TGRS.2007.905974

20. Krieger, G., N. Gebert, M. Younis, F. Bordoni, A. Patyuchenko, and A. Moreira, "Advanced concepts for ultra-wide-swath SAR imaging with high azimuth resolution," Proc. EUSAR, Friedrichshafen, Germany, 2008.
doi:10.1109/LGRS.2004.832700

21. Krieger, G., N. Gebert, and A. Moreira, "Unambiguous SAR signal reconstruction from nonuniform displaced phase center sampling," IEEE Geosci. Remote Sens. Lett., Vol. 1, No. 4, 260-264, Oct. 2004.
doi:10.1109/LGRS.2004.832700

22. Gebert, N., G. Krieger, and A. Moreira, "High resolution wide swath SAR imaging with digital beamforming --- Performance analysis, optimization and system design," Proc. EUSAR, Dresden, Germany, 2006.
doi:10.1109/TAES.2009.5089542

23. Gebert, N., G. Krieger, and A. Moreira, "Digital beamforming on receive: Techniques and optimization strategies for high-resolution wideswath SAR imaging," IEEE Trans. Aerosp. Electron. Syst., Vol. 54, No. 2, 564-592, Apr. 2009.
doi:10.1109/LGRS.2004.840610

24. Li, Z., H.Wang, T. Su, and Z. Bao, "Generation of wide-swath and high-resolution SAR images from multichannel small spaceborne SAR systems," IEEE Geosci. Remote. Sens. Lett., Vol. 2, No. 1, 82-86, Jan. 2005.
doi:10.1109/LGRS.2004.840610

Dr. Pingping Huang

Dr. Wei Xu

Dr. Weikong Qi