volume | PIER Journals

Abstract

This paper introduces an imaging algorithm with application of fractional Fourier transform (FrFT) for ground moving train imaging by Ku-band ground-based radar. In view of the fact that the train speed is varying when acrossing the radar beam, the multiple Doppler parameters are estimated corresponding to different range positions, i.e., they are estimated from different sections of data in FrFT domain, then the train is imaged section by section, and finally these sectional images are combined to get the full image of the train. Because traditional parameter estimation method by two-dimensionally searching the peaks in FrFT domain is inefficient, we transfer the parameter searching problem into an one-dimensional optimization problem, which can be solved with high efficiency by using the golden section searching method.

1. Almeida, L. B., "The fractional Fourier transform and time-frequency representations," IEEE Transactions on Signal Processing, Vol. 42, No. 11, 3084-3091, 1994.
doi:10.1109/78.330368 Google Scholar

2. Haldum Ozaktas, M., et al. "Convolution, filtering, and multiplexing in fractional Fourier domains and their relation to chirp and wavelet transforms," J. Opt. Soc. Am. A, Vol. 11, No. 2, 547-559, 1994.
doi:10.1364/JOSAA.11.000547 Google Scholar

3. Yetik, I. S. and A. Nehorai, "Beamforming using the fractional Fourier transform," IEEE Trans. Signal Processing, Vol. 51, No. 6, 1663-1668, 2003.
doi:10.1109/TSP.2003.811223 Google Scholar

4. Jang, S., W. Choi, T. K. Sarkar, et al. "Exploiting early time response using the fractional Fourier transform for analyzing transient radar returns," IEEE Trans. Antennas and Propagationm, Vol. 52, No. 11, 3109-3121, 2004.
doi:10.1109/TAP.2004.835165 Google Scholar

5. Amein, A. S. and J. J. Soraghan, "A new chirp scaling algorithm based on the fractional Fourier transform," IEEE Signal Process. Lett., Vol. 12, No. 10, 805-807, 2005.
doi:10.1109/LSP.2005.855547 Google Scholar

6. Borden, B., "The fractional Fourier transform and ISAR imaging," Inv. Probl. Lett., Vol. 16, No. 2, 5-8, 2000.
doi:10.1088/0266-5611/16/2/101 Google Scholar

7. Sun, H.-B., G.-S. Liu, H. Gu, et al. "Application of the fractional Fourier transform to moving target detection in airborne SAR," IEEE Transactions on Aerospace and Electronic Systems, Vol. 38, No. 4, 1416-1424, 2002.
doi:10.1109/TAES.2002.1145767 Google Scholar

8. Zhang, Y., X. Zhang, W. Zhai, et al. "Radar imaging and electromagnetic scattering analysis for ground moving target by ground-based stationary radar," Asia Pacific Microwave Conference, 2224-2227, 2009.
doi:10.1109/APMC.2009.5385425 Google Scholar

9. Zhang, Y. H., Y. Deng, W. S. Zhai, X. K. Zhang, and J. S. Jiang, "Time-frequency processing and analysis of radar imaging experiment data for a moving train," The 7th Iasted International Conference on Antennas, Radar and Wave Propagation, Cambridge, Massachusetts, USA, Nov. 1-3, 2010. Google Scholar

10. Zhang, Y., X. Zhang, W. Zhai, et al. "Moving train imaging by ground-based Ka-band radar," The 6th Loughborough Antennas & Propagation Conference, 413-416, Loughborough, 2009. Google Scholar

11. Xue, L., Optimization Techniques in Engineering, Tianjing University Press, Tianjing, 1989 (in Chinese)..

12. Lin, Q., T. Ran, and S. Zhou, "Detection and parameter estimation of multi-component LFM signal based on the fractional Fourier transform," Science in China: Series F Information Science, Vol. 47, No. 2, 184-198, 2004.
doi:10.1360/02yf0456 Google Scholar

13. Ozaktas, H. M., O. Arikan, M. A. Kutay, et al. "Digital computation of the fractional Fourier tansform," IEEE Transactions on Signal Processing, Vol. 44, No. 9, 2141-2150, 1996.
doi:10.1109/78.536672 Google Scholar

14. Cumming, I. G. and F. H. Wong, Digital Processing of Synthetic Aperture Radar Data: Algorithms and Implementation, Artech House Publishers, 2005.

Dr. Lingjuan Yu

Prof. Yunhua Zhang