Surface ship imaging technology is widely used in military and civilian applications. To resolve the problem of imaging moving target positioning blur on sea surface, this paper proposes a method for estimating the velocity of moving target using velocity synthetic aperture radar (VSAR). Firstly, the paper analyzes the imaging mechanism and constraints of VSAR method and establishes an imaging model based on phased array radar for surface ships. Then, the rate-frequency estimation method of the multi-antenna image domain is used to correct the azimuth offset, and the image moisture algorithm is used to estimate Doppler frequency modulation. Therefore, the adaptive focusing of the target image is completed. Finally, this method is used to simulate and calculate the surface motion ship to realize continuous dynamic imaging of the moving ship. Compared with the traditional single-channel SAR radar and track-interfering radar (ATI) algorithm, the rate-frequency estimation algorithm solves the shortcomings of the azimuth positioning accuracy and improves the positioning performance of the moving target ship under large-area sea conditions.
2. Renga, A. and A. Moccia, "Use of doppler parameters for ship velocity computation in SAR images," IEEE Transactions on Geo-Science and Remote Sensing, Vol. 54, No. 7, 3995-4011, 2016.
3. Ouchi, K. and S.-I. Hwang, "Improvement of ship detection accuracy by SAR multi-look crosscorrelation technique using adaptive CFAR," IEEE International Geoscience & Remote Sensing Symposium, IEEE, 3716-3719, 2010.
4. Jansen, R. W., R. G. Raj, L. Rosenberg, and M. A. Sletten, "Practical multichannel SAR imaging in the maritime environment," IEEE Transactions on Geoscience and Remote Sensing, Vol. 56, No. 7, 4025-4036, 2018.
5. Li, G., J. Xu, Y.-N. Peng, and X.-G. Xia, "Velocity layover solution in VSAR image," 2006 CIE International Conference on Radar, 16-19, Shanghai, China, 2006.
6. Friedlander, B. and B. Porat, "VSAR: A high resolution radar system for detection of moving targets," IEE Proceedings-Radar, Sonar and Navigation, Vol. 144, No. 4, 205-218, Aug. 1997.
7. Lombardini, F., et al., "Multibaseline ATI-SAR for robust ocean surface velocity estimation," IEEE Transactions on Aerospace and Electronic Systems, Vol. 40, No. 2, 417-433, 2004.
8. Wang, G., X.-G. Xia, and V. C. Chen, "Multi-frequency VSAR imaging of moving targets," Radar Processing, Technology and Applications IV, 159-169, Denver, CO, United States, September 1999.
9. Gang, L., X. Jia, Y.-N. Peng, and X.-G. Xia, "Location and imaging of moving targets using nonuniform linear antenna array SAR," IEEE Transactions on Aerospace and Electronic Systems, Vol. 43, No. 3, 1214-1220, 2007.
10. Sletten, M., et al., "The NRL multi aperture SAR system," 2015 IEEE Radar Conference, 0192-0197, Arlington, VA, USA, May 2015.
11. Sletten, M. A., et al., "Maritime signature correction with the NRL multichannel SAR," IEEE Transactions on Geoscience and Remote Sensing, Vol. 54, No. 11, 6783-6790, 2016.
12. Li, X. and X.-G. Xia, "Location and imaging of elevated moving target using multi-frequency velocity SAR with cross-track interferometry," IEEE Transactions on Aerospace and Electronic Systems, Vol. 47, No. 2, 1203-1211, 2011.
13. Li, J.-J., S.-Y. Wang, and W.-L. Hu, "Adaptive cell average CFAR detection based on multi-clutter distribution model," Journal of Air Force Radar Academy, Vol. 19, No. 3, 4-7, 2005.
14. Xiao, J., et al., "Estimation of the doppler frequency modulation ratio based on minimum entropy criteria for highly squinted SAR," Modern Radar, Vol. 35, No. 1, 46-54, 2013.
15. Finn, H. M. and R. S. Johnson, "Adaptive detection mode with threshold control as a function of spatially sampled clutter-level estimates," Rca Review, Vol. 29, No. 9, 414-464, 1968.
16. Xiong, Y.-F., et al., "Sea surface modeling based on the spectrum of ocean waves modeling and the FFT," Journal of Chongqing University of Technology (Natural Science), Vol. 28, No. 4, 77-82, 2014.
17. Donelan, M. A. and W. J. Pierson, "Radar scattering and equilibrium ranges in wind-generated waves with application to scatterometry," Journal of Geophysical Research Oceans, Vol. 92, No. C5, 4971-5029, 1987.
18. Durden, S. and J. Vesecky, "A physical radar cross-section model for a wind-driven sea with swell," IEEE Journal of Oceanic Engineering, Vol. 10, No. 4, 445-451, 1985.