This paper proposes an Extended Inverse Chirp-Z Transform (EICZT) algorithm to handle the high squint FMCW SAR data, where the conventional Inverse Chirp-Z Transform (ICZT) cannot work due to the failure in dealing with the range-variance of second- and higher-order range-azimuth coupling terms. A pre-processing operation is implemented in the azimuth-Doppler and range-time (Doppler-time) domain, where a perturbation function consisting of second-order and third-order range time variables is implemented to compensate the range variance of the second order range terms. Moreover, a new scaling factor is formulated to represent the Range Cell Migration (RCM), and further corrected by the presented EICZT approach. The proposed approach is analyzed and compared with the conventional ICZT. The simulated high squint SAR scene with nine targets is well focused by the proposed approach and the quality is greatly improved with respect the conventional ICZT. The proposed algorithm is also validated by the X-band high-resolution real SAR data.
2. Ender, , J. H. G. and A. R. Brenner, "PAMIR: A wide-band phased array SAR/MTI system," IEE Proc. | Radar Sonar Navig, Vol. 150, No. 3, 165-172, 2003.
3. Liu, , Q., , W. Hong, W. X. Tan, Y. Lin, Y. 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.
4. Wei, X., 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.
5. Buddendick, , H. , T. F. Eibert, and , "Bistatic image formation from shooting and bouncing rays simulated current distributions," Progress In Electromagnetics Research, Vol. 119, 1-18, 2011.
6. Banasiak, , R., , R. Wajman, D. Sankowski, and M. Soleimani, "Three-dimensional nonlinear inverstion of electrical capacitance tomography data using a complete sensor model," Progress In Electromagnetics Research,, Vol. 100, 219-234, 2010.
7. Park, , J.-I. and K.-T. Kim, "A comparative study on ISAR imaging algorithms for radar target identification," Progress In Electromagnetics Research , Vol. 108, 155-175, 2010.
8. 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.
9. Zhang, , M., , Y. W. Zhao, H. Chen, and W. Q. Jiang, "SAR imaging simulation for composite model of ship on dynamic ocean scene," Progress In Electromagnetics Research, Vol. 113, 395-412, 2011..
10. Zhao, , Y. W., , M. Zhang, and H. Chen, "An effcient ocean SAR raw signal simulation by employing fast Fourier transform," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 16, 2273-2284, 2010.
11. Wei, , S. J., X. L. Zhang, and J. Shi, "Linear array SAR imaging via compressed sensing," Progress In Electromagnetics Research, , Vol. 117, 299-319, 2011.
12. Bamler, , R., , "A comparison of range-Doppler and wavenumber domain SAR focusing algorithm," IEEE Trans. Geosci. Remote Sens., Vol. 40, No. 4, 706-713, 1992.
13. 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, 1996.
14. Cantalloube, , H. and P. Dubois-Fernandez, "Airborne X-band SAR imaging with 10 cm resolution: Technical challenge and preliminary results," IEE Proc. --- Radar Sonar Navig., Vol. 153, No. 2, 173-176, 2006.
15. Jin, , Y.-Q., , "Polarimetric scattering modeling and information retrieval of SAR remote sensing | A review of FDU work," Progress In Electromagnetics Research, Vol. 104, 333-384, 2010.
16. 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, 2001.
17. Mittermayer, , J., A. Moreira, and O. Loffeld, "Spotlight SAR data processing using the frequency scaling algorithm," IEEE Trans. Geosci. Remote Sens., Vol. 37, No. 9, 2198-2214, 1999.
18. Liu, Y., , Y. Deng, R. Wang, and X. Jia, "Bistatic FMCWBistatic FMCW SAR raw signal simulatior for extended scenes," Progress In Electromagnetics Research, Vol. 128, 479-502, 2012.
19. Natroshvili, , K., , O. Loffeld, H. Nies, A. M. Ortiz, and S. Knedlik, "Focusing of general bistatic SAR configuration data with 2-D inverse scaled FFT," IEEE Trans. Geosci. Remote Sens., Vol. 44, No. 10, 2718-2727, 2006.
20. Rabiner, L. R., , R. W. Schafer, and C. M. Rader, "The chirp-Z transform and its applications," IEEE Trans. Audio. Electro.,, Vol. 17, No. 2, 86-92, 1969..
21. Tang, , Y., M. D. Xing, and Z. Bao, "The polar format imaging algorithm based on double chirp-Z transforms," IEEE Geosci. Remote Sens. Lett., Vol. 5, No. 4, 610-614, 2008.
22. Lanari, , R., , S. Hensley, and P. A. Rosen, "Chirp Z-transform based SPECAN approach for phase-preserving ScanSAR image generation," IEE Proc. | Radar Sonar Navig., Vol. 145, No. 5, 1998.
23. Lanari, , R. , G. Fornaro, and , "A short discussion on the exact compensation of the SAR range-dependent range cell migration effect," IEEE Trans. Geosci. Remote Sens., Vol. 35, No. 6, 1446-1451, 1997.
24. Lanari, , R., "A new method for the compensation of the SAR range cell migration based on the chirp Z-transform," IEEE Trans. Geosci. Remote Sens., Vol. 33, No. 5, 1296-1299, 1995.