Ground-based synthetic aperture radar (GB-SAR) is an effective technique for monitoring over a widespread area. Save for the fact that it is installed on the ground, the GB-SAR operates in the same way as air-and satellite-borne microwave SAR remote sensing systems. By repeated acquisition of data and application of the repeat-pass interferometry principle, this technique can detect very small changes over a scene with a typically high temporal resolution of only a few minutes. In the system used in this study, interferometer error is less than 10% and the temporal resolution is approximately five minutes. Some applications require extensive monitoring capability; for instance, in this study, the GB-SAR technique was used to monitor a post-landslide surface in order to assess slope stability and to ensure the safety of the area. Whereas no major events were observed, the technique proved capable of detecting even small changes caused by snowfalls. The technique was also used to monitor the displacement of the ground surface in a tsunami-affected area in which the stability of the ground had come into question. The results of this assessment indicated that the distribution of displacement tended to be larger in waterfront areas and seemed to correlate to tidal effects. Although both of these measurement campaigns represent preliminary research, the advantages of the GB-SAR technique have been well illustrated. In this paper, the results of these measurements are provided, and the capability and potential of the technique are discussed.Index Terms-Disaster, ground-based synthetic aperture radar (GB-SAR), landslide, monitoring, radar interferometry, tsunami.

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We performed a Ground Based SAR (GB-SAR) andPiSAR simultaneous experiment over a flood test site. In this site, one prefab was constructed in a baseball field of a Nihon University in Chiba, Japan. The PiSAR observations were done for three days with different soil moisture condition of ~25%, ~50%, and 100%. Some GB-SAR experiments have been also done in two of three days and the scattering process are examined. Preliminary experiment with GB-SAR showed that Lband 0 from a double scattering of ground-wall is increased for a few dB, when a reflectivity of the ground is assumed to be 1. These increase are also confirmed in the test site for both PiSAR and GB-SAR. Furthermore, high resolution GB-SAR images show double and single bounce scattering from a metal bar behind the wooden board of the prefab. We conclude that Lband SAR has a enough ability to detect a flooding area in urban site.

ABSTRACT:Observation of sea ice thickness is one of key issues to understand regional effect of global warming. One of approaches to monitor sea ice in large area is microwave remote sensing data analysis. However, ground truth must be necessary to discuss the effectivity of this kind of approach. The conventional method to acquire ground truth of ice thickness is drilling ice layer and directly measuring the thickness by a ruler. However, this method is destructive, time-consuming and limited spatial resolution. Although there are several methods to acquire ice thickness in non-destructive way, ground penetrating radar (GPR) can be effective solution because it can discriminate snow-ice and ice-sea water interface. In this paper, we carried out GPR measurement in Lake Saroma for relatively large area (200m by 300m, approximately) aiming to obtain grand truth for remote sensing data.. GPR survey was conducted at 5 locations in the area. The direct measurement was also conducted simultaneously in order to calibrate GPR data for thickness estimation and to validate the result. Although GPR Bscan image obtained from 600MHz contains the reflection which may come from a structure under snow, the origin of the reflection is not obvious. Therefore, further analysis and interpretation of the GPR image, such as numerical simulation, additional signal processing and use of 200MHz antenna, are required to move on thickness estimation.

Ground-based synthetic aperture radar (GB-SAR) interferometry is a technique suitable for monitoring the movement and/or deformation of widespread targets remotely. The technique is capable of detecting a few tenths of millimeters. However, since the measurement is commonly carried out with a long-range distance, the influence of atmospheric condition can be a serious issue. A common and a practical way of correcting the influence on interferometric phase is based on coherent scatteres (CSs). In the present paper, a newly proposed method to detect CSs from measured data is discussed. The method detects CSs by taking the complex coherence of two SAR sub-images, which are formed from a data set. In order to form subimages, the measured data are interleaved and SAR processing is applied respectively. An experimental demonstration showed that the method can successfully detect deployed corner reflectors as CSs. Furthermore, the movement of a target can accurately be measured when atmospheric correction based on CSs, which are detected by the proposed method. Since the method requires only data sets in the analyzing time period to detect CSs, the proposed method has an advantage in the real-time detection of target movements over a conventional method based on dispersion index, which requires number of data sets.