Advantages and drawbacks in the use of non-contact radar techniques to perform dynamic measurements

Recent progresses have encouraged researchers to study and develop radar systems capable to perform dynamic measurements. The aim of this work is to investigate advantages and limitations in the use of this technique to perform dynamic measurements in the presence of multiple reflections, such as the ones generated by large civil structures. To this purpose, a radar system was tested in controlled conditions, imposing harmonic movements to a corner reflector and measuring the displacement. The tests were first performed using only one (shifting) reflecting body to assess the radar ability to perform dynamic measurements. Further tests were performed using one shifting reflecting body plus other three static reflecting bodies to simulate possible multiple reflections. The results obtained with the radar were compared with traditional measurement systems and with numerical simulations. The overall analysis shows how the presence of disturbing elements may cause distortions in the measured signals. The work is intended to warn against the use of this technique without a good a priori knowledge of the observed phenomenon.