Current advanced spaceborne synthetic aperture radar (SAR) systems may operate at multiple imaging modes, including conventional modes as stripmap, ScanSAR and spotlight, as well as the state-of-the-art SAR modes, e.g., sliding spotlight, TOPS (Terrain Observation by Progressive Scans) and inverse TOPS, etc. A novel image formation scheme for unified processing spaceborne SAR data was proposed, which significantly simplified complexity of SAR processor sub-system. The unified-model-coefficient (UMC) was defined for modeling all SAR modes by means of analyzing both imaging geometry and time-frequency diagram corresponding to each imaging mode, respectively. The unified mathematical formula for modeling all SAR modes echo signal was derived as a function of UMC. Consequently, a unified image formation scheme for accurately focusing spaceborne SAR data in an arbitrary mode was proposed, which integrates all of SAR image formation procedures into a standard three-step processing framework, namely, de-rotation, data focusing and re-sampling, which evidently improve efficiency and robustness of data processing sub-system. Computer simulation experiment results verify the effectiveness of the proposed scheme.
"A Novel Three-Step Image Formation Scheme for Unified Focusing on Spaceborne SAR Data," Progress In Electromagnetics Research,
Vol. 137, 621-642, 2013. doi:10.2528/PIER12122309
1. Ren, S., W. Chang, T. Jin, and Z. Wang, "Automated SAR reference image preparation for navigation," Progress In Electromagnetics Research, Vol. 121, 535-555, 2011. doi:10.2528/PIER11091405
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. Tian, B., D.-Y. Zhu, and Z.-D. Zhu, "A novel moving target detection approach for dual-channel SAR system," Progress In Electromagnetics Research, Vol. 115, 191-206, 2011.
4. Storvold, R., E. Malnes, and Y. Larsen, "SAR remote sensing of snow parameters in Norwegian areas-current status and future ," Journal of Electromagnetic Waves and Applications, Vol. 20, No. 13, 1751-1759, 2006. doi:10.1163/156939306779292192
5. 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
6. Zan, F. D. and A. M. Guarnieri, "TOPSAR: Terrain observation by progressive scans," IEEE Trans. on Geosci. Remote Sens., Vol. 44, No. 9, 2352-2360, 2006. doi:10.1109/TGRS.2006.873853
7. 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
8. Ren, X. Z., Y. Qin, and L. H. Qiao, "Interferometric properties and processing for spaceborne spotlight SAR," Progress In Electromagnetics Research B, Vol. 36, 267-281, 2012. doi:10.2528/PIERB11090609
9. Chan, Y. K., V. C. Koo, B. K. Chung, and H. T. Chuah, "Modified algorithm for real time SAR signal processing," Progress In Electromagnetics Research C, Vol. 1, 156-168, 2008.
10. Bamler, R. and M. Eineder, "ScanSAR processing using standard high precision SAR algorithm," IEEE Trans. on Geosci. Remote Sens. , Vol. 114, 17-32, 2011.
11. Wang, X. and D. Y. Zhu, "Range Doppler algorithm for bistatic SAR processing based on the improved lofield's bistatic formula," Progress In Electromagnetics Research Letter, Vol. 21, 161-169, 2011. doi:10.2528/PIERL11062609
12. Raney, R. K., H. Runge, and R. Bamler, "Precision SAR processing using chirp scaling," IEEE Trans. on Geosci. Remote Sens., Vol. 32, No. 4, 786-799, 1994. doi:10.1109/36.298008
13. 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. on Geosci. Remote Sens., Vol. 34, No. 5, 1123-1136, 1996. doi:10.1109/36.536528
14. Zhu, D., M. Shen, and Z. Zhu, "Some aspects of improving the frequency scaling algorithm for dechirped SAR data processing," IEEE Trans. on Geosci. Remote Sens., Vol. 46, No. 6, 1579-1588, 2008. doi:10.1109/TGRS.2008.916468
15. Liu, Q., W. Hong, W. Tan, Y. Lin, Y. P. Wang, and Y. Wu, "An improved polar format algorithm with performance analysis for geosynchronous circular SAR 2D imaging," Progress In Electromagnetics Research,, Vol. 119, 155-170, 2011. doi:10.2528/PIER11060503
16. 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.
17. 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.
18. Mao, X., D.-Y. Zhu, and Z.-D. Zhu, "Signatures of moving target in polar format spotlight SAR image," Progress In Electromagnetics Research, Vol. 92, 47-64, 2009. doi:10.2528/PIER09030908
19. Chen, J., J. H. Gao, Y. Q. Zhu, W. Yang, and P. B. 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, 527-542, 2012. doi:10.2528/PIER11121101
20. 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
21. Lanari, R., S. Zoffoli, E. Sansosti, G. Fornaro, and F. Serafino, "New approach for hybrid strip-map/spotlight SAR data focusing," IEE Proc. - Radar, Sonar, Navig., Vol. 148, No. 6, 363-372, 2001. doi:10.1049/ip-rsn:20010662
22. Prats, P., R. Scheiber, J. Mittermayer, A. Meta, and A. Moreira, "Processing of sliding spotlight and TOPS SAR data using baseband azimuth scaling," IEEE Trans. on Geosci. Remote Sens., Vol. 48, No. 2, 770-780, 2010. doi:10.1109/TGRS.2009.2027701
23. Yang, W., C. S. Li, J. Chen, and P. B. Wang, "Extend three-step focusing algorithm for sliding spotlight and TOPS data image formation," IEEE International Geoscience and Remote Sensing Symposium (IGARSS), 479-482, 2011.
24. Belcher, D. P. and C. J. Baker, "High resolution processing of hybrid strip-map/spotlight mode SAR," IEE Proc. - Sonar Navig., Vol. 143, No. 6, 366-374, 1996. doi:10.1049/ip-rsn:19960790
25. Cheng, H., T. Long, and Y. Tian, "An improved nonlinear chirp scaling algorithm based on curved trajectory in geosynchronous SAR," Progress In Electromagnetics Research, Vol. 135, 481-513, 2013.
26. Mittermayer, J., S. Wollstadt, P. Prats, R. Scheiber, and W. Koppe, "Staring spotlight imaging with TerraSAR-X," EEE International Geoscience and Remote Sensing Symposium (IGARSS), 1606-1608, 2012.