Fiber Bragg Grating Sensor System Based On CDMA Technology

With the limit of various factors, the multiplexing techniques which are most commonly used of sensor network are hard to meet many large structures'monitoring requirements for a large number of FBGs. Moreover, because of the spectrum aliasing phenomenon by measuring multiple FBGs simultaneously, the number of FBG sensor is decreased and the detection accuracy is lowered. This is also hard to meet the practical engineering requirements for large numbers of sensors and high precision of sensor. So the practical multiplexing query technique and the signal demodulation technology are key technologies of fiber grating sensing.In view of the above questions, the FBG sensor network are designed systemically based on research of domestic and abroad actualities on the FBG. And in need of the FBG sensing system, the FBG sensor network with CDMA technology is proposed.Firstly, the sensing principle of FBG sensor is analyzed, then some common network multiplexing technique and signal demodulation technology are analyzed based on some topological structure and the general model of FBG sensor network, and then present the scheme that introduce CDMA technology into the FBG sensing network.Secondly, in order to achieve the FBG multiplexing, the sensing grating is encoded by CDMA technology. The performance of sensor system can not be seriously affected by spectrum aliasing in the process of operation. It's also an effective method for the application of FBG sensor. And in order to improve the FBG sensor network performance, the sensor signals are demodulated by autocorrelation technology. And the encoding principle and demodulation method are explained in detail.Finally, this paper analyzes that the feasibility and validity of FBG sensor network with CDMA technology and autocorrelation signal demodulation technology, and this kind of FBG sensor network is suitable to applied with engineering test areas.