COBIS - Executive Summary

Opportunistic C-band Bistatic SAR Diffrential Interferometry (COBIS)

The project aims at prototyping architecture of a bistatic differential interferometry SAR using opportunistic the C band Sentinel 1 satellite, able to exploit best characteristics of both ground based SARs, classic satellite SAR interferometry and persistent scatterer techniques in monitoring ground movements like landslides, volcanoes, glaciers and large built structures.

By using both the Sentinel 1 transmitter and the ground-based transmitter, we intend to exploit the advantages brought by each of them. On one hand, the satellite-based transmitter ensures a high azimuth resolution (practically independent of the range) and illuminates a large area, but has a limited range resolution. On the other hand, the ground-based transmitter’s chirp bandwidth can be increased for a better range resolution, but the azimuth resolution is range dependent and the illuminated area relatively small.

In this context, from the point of view of deformation monitoring applications, the combination between the two transmitters allows the monitoring of a small critical area of interest with many ground-based acquisitions and a survey of the whole surrounding area with a small number of acquisitions corresponding to the satellite’s passes. Additionally, the opportunistic bistatic SAR offers a seamless integration into a wide area monitoring system (the SAR mounted on the satellite) and in same time the possibility to position the receivers according to the desired monitoring geometry, which is particularly relevant in case of steep slopes.