|
The continuous monitoring of ground deformation and structural movement has become an important task in
engineering. MetaSensing introduces a novel sensor system, the Fast Ground Based Synthetic Aperture Radar
(FastGBSAR), based on innovative technologies that have already been successfully applied to airborne SAR
applications. The FastGBSAR allows the remote sensing of deformations of a slope or infrastructure from up to a
distance of 4 km.
The FastGBSAR can be setup in two different configurations: in Real Aperture Radar (RAR) mode it is capable of
accurately measuring displacements along a linear range profile, ideal for monitoring vibrations of structures like bridges
and towers (displacement accuracy up to 0.01 mm). Modal parameters can be determined within half an hour.
Alternatively, in Synthetic Aperture Radar (SAR) configuration it produces two-dimensional displacement images with
an acquisition time of less than 5 seconds, ideal for monitoring areal structures like dams, landslides and open pit mines
(displacement accuracy up to 0.1 mm).
The MetaSensing FastGBSAR is the first ground based SAR instrument on the market able to produce two-dimensional
deformation maps with this high acquisition rate. By that, deformation time series with a high temporal and spatial
resolution can be generated, giving detailed information useful to determine the deformation mechanisms involved and
eventually to predict an incoming failure.
The system is fully portable and can be quickly installed on bedrock or a basement. The data acquisition and processing
can be fully automated leading to a low effort in instrument operation and maintenance. Due to the short acquisition time
of FastGBSAR, the coherence between two acquisitions is very high and the phase unwrapping is simplified enormously.
This yields a high density of resolution cells with good quality and high reliability of the acquired deformations. The
deformation maps can directly be used as input into an Early Warning system, to determine the state and danger of a
slope or structure.
In this paper, the technical principles of the instrument are described and case studies of different monitoring tasks are
presented.
|
