The Design Of Tower Deformation Monitoring Based On RFID Tags

This thesis presents a new method to monitor the spatial position of certain nodes in the transmission tower to reflect the deformation of the tower.First of all,we need to install the RFID tags on these nodes,different tags launch different frequency UHF signal,then install RFID card in different reference points on the ground used to receive carrier signals.RFID signal processor will transform analog signals to digital signals and stored,then waits for the data transfer instruction from the PC,and then sends the data packets to PC through the network port according to the UDP protocol.PC separates the different frequency signals through low-pass filter and high-pass filter,then we can get the phase difference of the carrier signals by Hilbert transformation in different receiver;Since carrier signals are different at different reference points,we can use the phase differences between these receiving points to find out the distance differences between the tags and the reference points.We can use the three independent distance equations to solve a tag XYZ coordinates.However,it is difficult to directly solve a tag coordinates by the distance formula,which can be solved by the Gauss-Newton iteration method.This thesis mainly has the following four parts of works.Firstly,it presents a new method to monitor the spatial position of certain nodes in the transmission tower to reflect the deformation of the tower,and the feasibility of the method was verified by relevant theories.Second,we verify the correctness about signal processing and data transmission on the MATLAB simulation platform;Third,we construct a complete hardware platform,the hardware platform has the tags and the signal processors.We perform some experiments of different types of tower deformation by the hardware platform,it is concluded that the platform can calculate spatial coordinates of the tags,the positioning error can be accurate to centimeter;Fourth,we perform some experiments to measure the effect on positioning under different frequency interval of tags,it is verified that under the same receive bandwidth the frequency interval of tags is bigger and the positioning error is smaller.