The research on high‐performance CO2 gas measurement using the Kalman‐wavelet algorithm

Abstract To measure the concentration of trace CO 2 with high performance, tunable diode laser absorption spectroscopy technology was adopted in this paper. Kalman‐wavelet algorithm was used to depress the detector noise and optical interference fringe noise. Experimental results show that the second harmonic signal‐to‐noise ratio of the measuring system at 50ppmv CO 2 gas was improved by 2.06 times compared with no filtering. Under different CO 2 concentrations, the measuring errors are from 2.57% to 2.66%. According to Allan variance analysis, the minimum detection limit was reduced to 5.2 ppmv with the optimal integration time of 61 s. And, the standard deviation value was decreased from 33 to 19 ppmv during long‐term measurement, which can guarantee the high‐performance measurement of CO 2 gas.