Abstract: Millimeter-wave radar can obtain high-frequency, high-precision deformation displacement data, but because the radar can only obtain the target radial deformation component, it is urgent for radar distributed network monitoring to obtain the target three-dimensional deformation. In this paper, the self-developed ground-based millimeter-wave radar system is firstly briefly introduced, and then a three-dimensional deformation displacement and spectral monitoring method of the target at the special point of the building structure is proposed on the basis of the RF signal model of the system, and then the fire collapse monitoring and early warning test is carried out for truss factory buildings, and the three-dimensional deformation results of the key targets of the building structure are obtained through the synchronous monitoring of the 3 radars. The study shows that the distributed network monitoring of millimeter wave radar can effectively obtain the three-dimensional deformation components of the target at the special point of the building under the real fire scene, and provide effective data input for the monitoring and warning model of building fire collapse, which can be popularized and applied in the future in the aspects of emergency rescue and health monitoring of building engineering.

Key words: millimeter-wave radar, truss construction, distributed network monitoring, collapse deformation