The synthetic aperture radar (SAR) is a widely used instrument for high-resolution imaging from aircraft or satellite platforms. In the paper, the problem of the defocusing of multi-look SAR images by uncompensated phase errors presented in the received data is analyzed. It is shown that the phase errors on a multi-look processing interval can be effectively described in terms of local quadratic and local linear phase errors. Approximate analytical expressions are derived to describe the azimuth resolution degradation. Criteria for acceptable phase errors are given. The obtained results are verified by numerical simulations. The approach is illustrated by two typical motion errors: slow deflections of a SAR platform trajectory from a reference flight line and periodic trajectory deviations.
Oleksandr O. Bezvesilniy,
Ievgen M. Gorovyi,
Dmytro M. Vavriv,
"Effects of Local Phase Errors in Multi-Look SAR Images," Progress In Electromagnetics Research B,
Vol. 53, 1-24, 2013. doi:10.2528/PIERB13043007
1. Oliver, C. and S. Quegan, Understanding Synthetic Aperture Radar Images, Artech House, Norwood, MA, 1999.
2. Carrara, W. G., R. S. Goodman, and R. M. Majewski, Spotlight Synthetic Aperture Radar: Signal Processing Algorithms, Artech House, Boston, London, 1995.
3. Cumming, I. G. and F. H. Wong, Digital Processing of Synthetic Aperture Radar Data: Algorithms and Implementation, Artech House, Norwood, MA, 2005.
4. Franceschetti, G. and R. Lanari, Synthetic Aperture Radar Processing, CRC Press, 1999.
5. Bezvesilniy, O. O. and D. M. Vavriv, "Synthetic aperture radar systems for small aircrafts: Data processing approaches," Recent Advances in Aircraft Technology, Chapter 20, 465-498, R. K. Agarwal Ed., InTech, Croatia, 2012.
6. Vavriv, D. M. and O. O. Bezvesilniy, "Developing SAR for small aircrafts in Ukraine," Proceedings of the 2011 IEEE MTT-S International Microwave Symposium (IMS 2011), 1-4, Baltimore, USA, Jun. 5-10 2011.
7. Bezvesilniy, O. O., I. M. Gorovyi, S. V. Sosnytskiy, V. V. Vinogradov, and D. M. Vavriv, "Multi-look stripmap SAR processing algorithm with built-in correction of geometric distortions," Proceedings of the European Conference on Synthetic Aperture Radar (EUSAR 2010) , 712-715, Aachen, Germany, Jun. 7-10, 2010.
8. Bezvesilniy, O. O., I. M. Gorovyi, S. V. Sosnytskiy, V. V. Vinogradov, and D. M. Vavriv, "SAR processing algorithm with built-in geometric correction," Radio Physics and Radio Astronomy, Vol. 2, No. 3, 277-286, 2011. doi:10.1615/RadioPhysicsRadioAstronomy.v2.i3.100
9. Bezvesilniy, O. O., I. V. Dukhopelnykova, V. V. Vinogradov, and D. M. Vavriv, "Retrieving 3-D topography by using a single-antenna squint-mode airborne SAR," IEEE Transactions on Geoscience and Remote Sensing, Vol. 45, No. 11, 3574-3582, 2007. doi:10.1109/TGRS.2007.902963
10. Bezvesilniy, O. O., I. M. Gorovyi, V. V. Vinogradov, and D. M. Vavriv, "Multi-look radiometric correction of SAR images," Radio Physics and Radio Astronomy, Vol. 3, No. 2, 169-177, 2012. doi:10.1615/RadioPhysicsRadioAstronomy.v3.i2.90
11. Bezvesilniy, O. O., I. M. Gorovyi, and D. M. Vavriv, "Estimation of phase errors in SAR data by local-quadratic map-drift autofocus," Proceedings of the 13th International Radar Symposium (IRS-2012), 376-381, Warsaw, Poland, May 23-25, 2012.
13. Curlander, J. C., et al. Fundamentals and special problems of synthetic aperture radar, AGARD Lecture Series, 1992.
14. Brown, W. M., "SAR resolution in the presence of phase errors," IEEE Transactions on Aerospace and Electronic Systems, Vol. 24, No. 6, 808-814, 1988. doi:10.1109/7.18648
15. Fornaro, G., G. Franceschetti, and S. Perna, "Motion compensation errors: Effect on the accuracy of airborne SAR images," IEEE Transactions on Aerospace and Electronic Systems, Vol. 41, No. 4, 1338-1352, 2005.
16. Fornaro, G., "Trajectory deviations in airborne SAR: Analysis and compensation," IEEE Transactions on Aerospace and Electronic Systems, Vol. 35, No. 3, 997-1009, 1999. doi:10.1109/7.784069
17. Marechal, N., "High frequency phase errors in SAR imagery and implications for autofocus," International Geoscience and Remote Sensing Symposium (IGARSS 96), Vol. 2, 1233-1240, USA, 1996.
18. Sheng, W., T. Lv, and J. Cao, "The deviation in the phase of SAR echoes due to INS error," Chinese Journal of Electronics, Vol. 18, No. 1, 177-182, 2009.
19. Mao, Y., "Error analysis of SAR motion compensation," IEEE International Conference on Imaging Systems and Techniques (IST), 377-380, Beijing, China, 2012.
20. Zelenka, J. S., "SAR image quality effects of damped phase and amplitude errors," Proceedings of the IEEE National Radar Conference, 61-67, USA, 1988.
21. Koo, V. C., Y. K. Chan, G. Vetharatnam, M. Y. Chua, C. H. Lim, C.-S. Lim, C. C. Thum, T. S. Lim, Z. bin Ahmad, K. A. Mahmood, M. H. Bin Shahid, C. Y. Ang, W. Q. Tan, P. N. Tan, K. S. Yee, W. G. Cheaw, H. S. Boey, A. L. Choo, and B. C. Sew, "A new unmanned aerial vehicle synthetic aperture radar for environmental monitoring," Progress In Electromagnetics Research, Vol. 122, 245-268, 2012. doi:10.2528/PIER11092604