A Comparative Study on Radar Interferometry for Vibrations Monitoring on Different Types of Bridges

A great number of bridges have been built in the world, which are very important for economic and society developments. Thus, the bridge monitoring is vital and is also a hot topic in recent years. Many bridge monitoring methods have been presented to monitor the bridge vibration. For example, some bridge monitoring methods require the sensors directly contact with the bridge, which might be difficult to install and maintain. In addition, some remote monitoring instruments are expensive and sensitive to the environment. In this paper, a bridge monitoring radar with a central frequency of 36.05 GHz is devised based on a millimeter-wave technology to measure the bridge vibration. It has a super-range resolution of 0.5 m and a high deformation measure precision of $56~\mu \text{m}$ . Experiments on a high-speed railway bridge and a large cable suspended bridge are performed to verify the effectiveness of the radar interferometry for accurate and precise monitoring of the vibration types and magnitudes of these bridges.