Development of a Ground-Based Synthetic Aperture Radar (GB-SAR) System and its Applications to Environment Monitoring

We have developed a ground-based polarimetric broadband SAR system for non-invasive ground-truth validation in polarimetric SAR remote sensing of terrestrial vegetation cover. This system consists of a vector network analyzer, one dual polarized antenna, and an antenna positioner. It can be operated in a frequency range from 50 MHz to 20 GHz, with a scanning aperture of 20 m in the horizontal and 1.5 m in the vertical direction. Tests carried out with standard reflectors showed that the polarimetric measurement capabilities of this system are satisfactory. Using the polarimetric ground-based SAR (GB-SAR) system, we carried out measurements on a specific vegetation cover pertinent to the remote sensing of forested regions within Sendai City, consisting of three different kinds of trees common within the Kawauchi Campus of Tohoku University. The same system can be used for interferometric use. Our test showed that the system can detect a deformation of the surface of a wooden building at the accuracy of less than 1cm. We also applied the same system for the monitoring of a natural cliff. The target was more than 50m apart form the radar location, and we could obtain the image of the cliff. We believe this system can be used for a real-time monitoring of the possible ground slide, and other targets such as large concrete constructions and buildings