A microwave interferometer with imaging capability for remote measurements of building displacements

In this paper the authors report some experimental activities carried out in Italy during the last few years, aimed at verifying the effectiveness of the use of coherent radar imaging to retrieve information on buildings deformations. Maps of differential phase obtained by means of a microwave interferometer with imaging capabilities are presented. Images were obtained by a synthetic-aperture interferometric radar making use of continuous-wave step-frequency waveform. The deformation maps and the measurement of some mechanical parameters – as the oscillating frequency and the amplitude of the vibrating modes of the observed structures – were performed remotely with sub-millimetre accuracy.