volume | PIER Journals

Abstract

For inverse synthetic aperture radar (ISAR) imaging of multiple targets, range profiles of different targets are sometimes coupled together, resulting in the ineffectiveness of traditional imaging method, while the couplings in range domain may behave differently in time-frequency domain, and the Doppler histories of different targets are potentially separable. Then the time-frequency analysis method can be utilized for signal separation of multiple targets. Notice that the nonuniform motions of targets may make the time-frequency curves changeful, and accordingly, some preprocessing are needed. In this paper, a novel ISAR imaging method based on modified keystone transform (MKT), short-time Fourier transform (STFT), and Hough transform (HT) is proposed. The radar echoes of multiple targets are approximated to a second-order polynomial. The MKT is firstly utilized to correct the range curvatures. Secondly, the signal in each range cell is transformed into time-frequency domain through the STFT. Meanwhile, HT theory and mask matrix are adopted in time-frequency curves' separation of different targets. Thirdly, after inverse STFT, the separated time-frequency curves are respectively back to the range domain, and the range profiles of different targets are successfully separated. Eventually, with further motion compensation and precise imaging, focused ISAR images of different targets are achieved. Simulation results demonstrate the validity of the proposed method.

1. Zheng, J. B., T. Su, W. T. Zhu, and Q. H. Liu, "ISAR imaging of targets with complex motions based on the Keystone time-chirp rate distribution," IEEE Geoscience and Remote Sensing Letters, Vol. 11, No. 7, 1275-1279, 2014.
doi:10.1109/LGRS.2013.2291992 Google Scholar

2. Lv, Q., T. Su, and J. Zheng, "Inverse synthetic aperture radar imaging of targets with complex motion based on the local polynomial ambiguity function," Journal of Applied Remote Sensing, Vol. 10, No. 1, 015019, 2016.
doi:10.1117/1.JRS.10.015019 Google Scholar

3. Sun, S. B. and G. Liang, "ISAR imaging of complex motion targets based on Radon transform cubic chirplet decomposition," International Journal of Remote Sensing, Vol. 39, No. 6, 1770-1781, 2018.
doi:10.1080/01431161.2017.1415485 Google Scholar

4. Li, Y. C., M. D. Xing, J. H. Su, Y. H. Quan, and Z. Bao, "A new algorithm of ISAR imaging for maneuvering targets with low SNR," IEEE Transactions on Aerospace & Electronic Systems, Vol. 49, No. 1, 543-557, 2013.
doi:10.1109/TAES.2013.6404119 Google Scholar

5. Qian, J., X. Lv, M. Xing, L. Li, and Z. Bao, "Motion parameter estimation of multiple ground fast-moving targets with a three-channel synthetic aperture radar," IET Radar, Sonar & Navigation, Vol. 5, No. 5, 582-592, 2011.
doi:10.1049/iet-rsn.2010.0111 Google Scholar

6. Lian, M. and Y. Jiang, "Time-frequency analysis for moving ship targets in GEO spaceborne/airborne bistatic SAR imaging based on a GEO satellite transmitter," International Journal of Remote Sensing, Vol. 38, No. 23, 7389-7404, 2017.
doi:10.1080/01431161.2017.1375615 Google Scholar

7. Li, J., R. Wu, and V. C. Chen, "Robust autofocus algorithm for ISAR imaging of moving targets," IEEE Transactions on Aerospace and Electronic Systems, Vol. 37, No. 3, 1056-1069, 2001.
doi:10.1109/7.953256 Google Scholar

8. Muñoz-Ferreras, J. M., F. Pérez-Martínez, and M. Datcu, "Generalisation of inverse synthetic aperture radar autofocusing methods based on the minimisation of the Renyi entropy," IET Radar Sonar & Navigation, Vol. 4, No. 4, 586-594, 2010.
doi:10.1049/iet-rsn.2009.0027 Google Scholar

9. Tian, J., W. Cui, X. L. Lv, and S. Wu, "Joint estimation algorithm for multi-targets’ motion parameters," IET Radar Sonar & Navigation, Vol. 8, No. 8, 939-945, 2014.
doi:10.1049/iet-rsn.2013.0346 Google Scholar

10. Li, Y., Y. Fu, X. Li, and L.-W. Li, "ISAR imaging of multiple targets using particle imaging of multiple targets using particle swarm optimisation-adaptive joint time frequency approach," IET Signal Processing, Vol. 4, No. 4, 343-351, 2010.
doi:10.1049/iet-spr.2009.0046 Google Scholar

11. Tian, J., W. Cui, and S. Wu, "A novel method for parameter estimation of space moving targets," IEEE Geoscience & Remote Sensing Letters, Vol. 11, No. 2, 389-393, 2013.
doi:10.1109/LGRS.2013.2263332 Google Scholar

12. Li, X., G. Cui, W. Yi, and L. Kong, "A fast maneuvering target motion parameters estimation algorithm based on ACCF," IEEE Signal Processing Letters, Vol. 22, No. 3, 270-274, 2014.
doi:10.1109/LSP.2014.2358230 Google Scholar

13. Park, S. H., H. T. Kim, and K. T. Kim, "Segmentation of ISAR images of targets moving in formation," IEEE Transactions on Geoscience & Remote Sensing, Vol. 48, No. 4, 2099-2108, 2010.
doi:10.1109/TGRS.2009.2033266 Google Scholar

14. Bai, X. R., F. Zhou, M. D. Xing, and Z. Bao, "A novel method for imaging of group targets moving in a formation," IEEE Transactions on Geoscience and Remote Sensing, Vol. 50, No. 1, 221-231, 2012.
doi:10.1109/TGRS.2011.2160185 Google Scholar

15. Martorella, M., E. Giusti, F. Berizzi, A. Bacc, and E. Dalle Mese, "ISAR based techniques for refocusing non-cooperative targets in SAR images," IET Radar Sonar & Navigation, Vol. 6, No. 5, 332-340, 2012.
doi:10.1049/iet-rsn.2011.0310 Google Scholar

16. Park, S. H., K. K. Park, J. H. Jung, H. T. Kim, and K. T. Kim, "ISAR imaging of multiple targets using edge detection and hough transform," Journal of Electromagnetic Waves and Applications, Vol. 22, No. 2-3, 365-373, 2008.
doi:10.1163/156939308784160622 Google Scholar

17. Choi, G. G., S. H. Park, H. T. Kim, and K. T. Kim, "ISAR imaging of multiple targets based on particle swarm optimization and hough transform," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 14-15, 1825-1834, 2009.
doi:10.1163/156939309789932322 Google Scholar

18. Xing, M. D., R. B. Wu, J. Q. Lan, and Z. Bao, "Migration through resolution cell compensation in ISAR imaging," IEEE Geoscience & Remote Sensing Letters, Vol. 1, No. 2, 141-144, 2004.
doi:10.1109/LGRS.2004.824766 Google Scholar

19. Lv, X. L., M. D. Xing, S. H. Zhang, and Z. Bao, "Keystone transformation of the Wigner-Ville distribution for analysis of multicomponent LFM signals," Signal Processing, Vol. 89, No. 5, 791-806, 2009.
doi:10.1016/j.sigpro.2008.10.029 Google Scholar

20. Kirkland, D., "Imaging moving targets using the second-order keystone transform," IET Radar Sonar & Navigation, Vol. 5, No. 8, 902-910, 2011.
doi:10.1049/iet-rsn.2010.0304 Google Scholar

21. Zhang, J., T. Su, Y. Li, and J. Zheng, "Radar high-speed maneuvering target detection based on joint second-order keystone transform and modified integrated cubic phase function," Journal of Applied Remote Sensing, Vol. 10, No. 3, 035009, 2016.
doi:10.1117/1.JRS.10.035009 Google Scholar

22. Ruan, H., Y. Wu, X. Jia, and W. Ye, "Novel ISAR imaging algorithm for maneuvering targets based on a modified Keystone transform," IEEE Geoscience & Remote Sensing Letters, Vol. 11, No. 1, 128-132, 2013.
doi:10.1109/LGRS.2013.2250250 Google Scholar

23. Lin, Q. Q., Z. P. Chen, Y. Zhang, and J. Z. Lin, "Coherent phase compensation method based on direct if sampling in wideband radar," Progress In Electromagnetics Research, Vol. 136, 753-764, 2013.
doi:10.2528/PIER12122203 Google Scholar

24. Zhu, D. Y., Y. Li, and Z. D. Zhu, "A Keystone transform without interpolation for SAR ground moving-target imaging," IEEE Geoscience and Remote Sensing Letters, Vol. 4, No. 1, 18-22, 2007.
doi:10.1109/LGRS.2006.882147 Google Scholar

25. Zhang, L. and X. H. He, "Approach for airborne radar ISAR imaging of ship target," IEEE International Conference on Signal Processing, 2137-2141, 2010. Google Scholar

26. Wang, J., J. Wang, Y. Wu, Y. Zhu, Z. Luo, and Y. Deng, "Phase adjustment for multistatic passive radar imaging based on image entropy and image contrast," International Journal of Remote Sensing, Vol. 37, No. 18, 4460-4485, 2016.
doi:10.1080/01431161.2016.1213919 Google Scholar

Dr. Jia Zhao

Professor Yunqi Zhang

Dr. Xin Wang

Dr. Sheng Wang

Dr. Feng Shang