Improving detection limit of non-dispersive infrared gas sensor with high precision by matched filtering

Non-dispersive infrared (NDIR) gas sensors have the disadvantage of high limit of detection (LOD), and the signal-to-noise ratio (SNR) has a significant impact on LOD. This paper proposes the application of matched filtering to NDIR gas sensors, a weak signal detection method that maximizes the SNR, improving the LOD. Experimental results show that matched filtering outperforms traditional methods, achieving an LOD of 1.131 ppm, while the LOD based on lock-in amplification is 7.350 ppm. The full-scale relative error and relative standard deviation (RSD) of the sensor in detecting different gas concentrations were optimized and improved. This approach provides a significant algorithmic improvement in the detection accuracy of NDIR gas sensors, offering potential for the detection of gases with less prominent absorption peaks, such as hydrogen.