volume | PIER Journals

Abstract

GBSAR has been widely used in landslides monitoring for its high precision in deformation monitoring and portable characteristic in natural environments. When monitor slides in mountainous areas, GBSAR cannot only work in positive mode, and its antennas may be directed to the target with a large squint angle. Unfortunately, normal range doppler imaging algorithm is not used well in such applications. Thus, a correction method of RD algorithm for SAR imaging with a squint angle has been proposed in the paper. Because the monitoring target may be far away from the view center of the GBSAR, echo of the target may be side lobe resided, when it is received by the radar's sensor. Simultaneously, distance between the sensor and imaging target changes with the azimuth time. Therefore, target in the SAR image would not be focused in one range bin if no range correction method was used. Thus, phase correction methods were used in the paper. The phase error was corrected in range domain and azimuth domain, respectively. It avoids 2D FFT processing. Thus, it may use few time and work. In this way, the GBSAR would have real time processing ability in the future. In the paper, a GBSAR was designed and used in slide monitoring applications in western mountains of Beijing. The experiment result shows that the system can measure target's micro deformation in mm levels with a high precision.

1. Monserrat, O., M. Crosetto, and G. Luzi, "A review of ground-based SAR interferometry for deformation measurement," ISPRS Journal of Photogrammetry & Remote Sensing, Vol. 93, No. 7, 40-48, 2014.
doi:10.1016/j.isprsjprs.2014.04.001

2. Iglesias, R., A. Aguasca, X. Fabregas, et al. "Ground-based polarimetric SAR interferometry for the monitoring of terrain displacement phenomena - Part I: Theoretical description," IEEE Journal of Selected Topics in Applied Earth Observation and Remote Sensing, Vol. 8, No. 3, 980-993, 2015.

3. Iglesias, R., A. Aguasca, X. Fabregas, et al. "Ground-based polarimetric SAR interferometry for the monitoring of terrain displacement phenomena - Part II: Applications," IEEE Journal of Selected Topics in Applied Earth Observation and Remote Sensing, Vol. 8, No. 3, 994-1007, 2015.

4. Luzi, G., O. Monserrat, M. Crosetto, et al. "Ground-based SAR interferometry applied to landslide monitoring in mountainous areas," Mountain Risks Conference, Florence, Italy, 2010.

5. Nico, G., L. Borrelli, and A. Pasquale, "Monitoring of an ancient landslide phenomenon by GBSAR technique in the Maierato Town (Calabria, Italy)," Engineering Geology for Society and Territory, Vol. 2, 129-133, 2015.
doi:10.1007/978-3-319-09057-3_12

6. Liu, X., X. Tong, K. Ding, et al. "Measurement of long-term periodic and dynamic deflection of the long-span railway bridge using microwave interferometry," IEEE Journal of Selected Topics in Applied Earth Observation and Remote Sensing, Vol. 8, No. 9, 4531-4538, 2015.
doi:10.1109/JSTARS.2015.2464240

7. Gentile, C., "Deflection measurement on vibrating stay cables by non-contact microwave interferometer," NDT&E International, Vol. 43, No. 3, 231-240, 2010.
doi:10.1016/j.ndteint.2009.11.007

8. Liu, X., W. Chang, and Y. Guan, "Study of squint imaging algorithm for FMCW SAR," 2016 Progress In Electromagnetic Research Symposium (PIERS), 1384-1388, Shanghai, China, August 8–11, 2016.

9. Liang, Y., H. Wang, M. Xing, et al. "Imaging study of high squint SAR based on FMCW," IEEE 1st Asian and Pacific Conference on Synthetic Aperture Radar, Huangshan, China, 2007.

10. Chen, P. and J. Kiang, "An improved range-doppler algorithm for SAR imaging at high squint angles," Progress In Electromagnetics Research M, Vol. 53, 41-52, 2017.
doi:10.2528/PIERM16111601

11. Yuan, Y., S. Chen, and H. Zhao, "An improved RD algorithm for maneuvering bistatic forward-looking SAR imaging with a fixed transmitter," Sensors, Vol. 17, No. 5, 1152, 2017.
doi:10.3390/s17051152

12. Zhou, Z., Y. Li, Y. Wang, et al. "Extended multiple aperture mapdrift based doppler parameter estimation and compensation for very high squint airborne SAR imaging," Sensors, Vol. 19, No. 1, 213, 2019.
doi:10.3390/s19010213

13. Xiao, J. and X. Hu, "A modified RD algorithm for airborne high squint mode SAR imaging," IEEE 1st Asian and Pacific Conference on Synthetic Aperture Radar, Huangshan, China, 2007.

14. Bara, M., R. Scheiber, A. Broquetas, et al. "Interferometric SAR signal analysis in the presence of squint," IEEE Transactions on Geoscience and Remote Sensing, Vol. 38, No. 5, 2164-2178, 2000.
doi:10.1109/36.868875

15. Shao, Z., X. Zhang, and Y. Li, "Analysis and validation of super-resolution micro-deformation monitoring radar," Progress In Electromagnetics Research M, Vol. 62, 41-50, 2017.
doi:10.2528/PIERM17072612

16. Qi, X., G. Sun, and Y. Wang, "An advanced range doppler algorithm for forward squint SAR," Computer Measurement & Control, Vol. 23, No. 9, 3165-3168, 2015.

Dr. Zelong Shao

Dr. Xiangkun Zhang

Prof. Yingsong Li