A Multi-Point Radio Displacement Measurement Method for Testing Quake-Proof Structure

In this paper, we propose a remote 3-D displacement measurement method using the radio wave for indoor shaking table facilities. It also shows the effectiveness of the proposed method by some radio experiments using a shaking table. The proposed measurement system consists of simple transmitters attached to each reference point and several receiving antennas at different places connected with a digital signal processing unit. The locations of the transmitters are simultaneously estimated by observing the phase differences between signals at receiving antennas. This prototype radio experimental system consists of 3 transmitters of frequency 2.45GHz, 4 receiving antennas and a microcomputer. We made the demonstration for the reconstructions of the 0.1Hz and 2Hz sinusoidal excitations at 3 reference points of the testing structure on the shaking table. The accuracy of estimated displacement was several centi-meters to several mili-meters.