Research Of The Key Technologies Of Portable Multi-component Gas Monitoring Equipment

Environment monitoring is an important method to grasp the environmental quality and predict pollution trend, which is the main basis of all government administration and public accessing to the environmental information. Fourier transform infrared remote sensing (FTIR) is widely used in the early warning of harmful gas, environmental monitoring and other fields, with the advantage of long-range, fast, unnecessary sampling and so on .Focus on FTIR sensing system, the work of this dissertation is listed as follows:(1) Discriminator is key part of FTIR remote sensing system. Based on the deep analysis of operating characteristics of discriminator, the central processor with high-speed, floating-point and open multimedia application plant (OMAP), is assisted by high-speed peripherals to complete the discriminator platform. Discriminator which is developed in this paper has the advanrtage of high speed operation, the ability of loading complex algorithm, the efficiency of communications and operation reliability and so on.(2) Research on data transmission based on Ethernet technology.To realize network and distributed environment monitoring system, this paper sets a basic model of spectrum data transmission based on embedded TCP/IP protocol and realizes remote control of the main control computer.(3) Research on algorithm of spectrum data preprocessing. Efficient spectrum data preprocessing and precise recognition algorithm are the key technologies to improve the performance of discriminator. The wavelet packet transform is used in spectrum data preprocessing in this dissertation, which can remove the noise and baseline drift at the same time.The appropriate wavelet functions and threshold rules are selected to improve algorithm accuracy by comparing the parameters of the normalized correlation coefficient (NCC), the root-mean-square error (RMSE) and the signal to noise ratio (SNR).