RaMon - Radar-Based Spatial Monitoring (2012)

Radar-Based Spatial Monitoring (RaMon):

The RaMon project deals with the monitoring of geoobjects in the context of exploitation of natural resources and energy supply. The main objectives are the detection of the deformation and the modelling of the dynamical behaviour of geoobjects. 
RaMon is a collaborative project within the framework of the Technical University of Lower Saxony. It is structured in three sub-projects, which are treated at the Clausthal University of Technology, the Brunswick University of Technology and the Leibniz University Hannover. 

Project at the Leibniz University Hannover:

Persistent Scatterer Interferometry (PSI) is an extension of the classical interferferometry with the objective to estimate surface deformation. 
 PSI is based on two main ideas. On the one hand, the analysis is restricted to resolution cells exhibiting a coherent bachscattering behaviour in time. These resolution cells are referred to as Persistent Scatterers (PS). On the other hand, a stack of interferograms is used in order to estimate the atmospheric disturbance. 
 The PSI technique has originally been designed for data of SAR sensors with a ground resolution of approximately 10 meter. A precise assignment of PS to objects within the scene was hardly possible due to this quite coarse resolution. Therefore, none or just few knowledge about the relationship of the PS to each other was used in the analysis. However, this has changed fundamentally since the start of the TerraSAR-X mission, which is mainly due to the better ground resolution of this sensor.
 Our project has two goals. The first is the assignment of PS to single buildings or building features enabling a detailed description and modelling of the deformation of a building or parts of a building. In a first step different assignment strategies are examined. One strategy is exemplarily displayed in Fig. 1. 
 Thereby typical building features like the outline and rows of windows are extracted from a 3D city model and projected into the radar geometry. Identified PS can now be matched with this auxiliary data set and can be assigned to buildings or building features.

Fig. 1: Overlay of a SAR-amplitude image with typical building parts like outline and window rows. The building framed in green is the Kollhoff-Tower at the Potsdamer Platz in Berlin.

The second goal is the detection of patterns in the PS set, like regular structures originating from rows of windows or balconies. The detection of those structures can support the PSI analysis in respect of the examination of ground deformation.