基于非分散红外吸收光谱技术，利用CO气体分子在4.6 μm处的基频吸收带，采用宽带红外热光源和双通道热释电探测器，研制了一种用于早期火灾探测的红外CO传感系统。根据系统检测原理，对CO分子在红外波段的吸收谱线进行了选择；推导了光学矩阵理论，设计并优化了气室结构，优化后气室的吸收光程达到180 cm。对研制的锁相放大器进行标定，1σ检测下限为0.15 μV，背景噪声为38.89~43.23 μV。对传感系统的性能进行了实验测试。结果显示，CO的检测分辨率优于2.00×10^-5，响应时间为35~38 s。对纯氮气（N₂）样品进行了长达80 min的监测，其浓度波动范围为-1.42×10^-5~1.51×10^-5，当积分时间为0.25 s时，系统的检测下限为1.54×10^-6；当积分时间为300 s时，系统的理论检测下限可达3.50×10^-7。引入卡尔曼滤波算法来提高系统的稳定性，对纯氮气进行长达80 min的探测，引入该算法后系统的检测下限降低到原来的23%，同时，当积分时间为0.25 s时，检测下限降低到3.60×10^-7。利用该传感系统，开展了棉花、纸张和木材的火灾阴燃实验，研究了CO浓度随阴燃时间的变化关系，验证了可通过CO浓度的变化来探测火灾发生的方法，证实了该传感系统呈现出良好的早期火灾探测能力。

China is not only a large agricultural country, but also one of the countries suffering from the most serious agricultural disasters in the world. Early fire detection can help to avoid greater losses. Crops have a period of smoldering before the open flame. Due to lack of oxygen, the combustion is extremely insufficient, and a small amount of carbon monoxide (CO) with a relatively stable concentration will be produced. Therefore, the occurrence of early fire can be judged by detecting gas-phase CO. Non-Dispersive Infrared (NDIR) absorption spectroscopy was used in this paper. Based on the absorption band of CO gas molecules at 4.6 μm, a differential infrared CO sensor system for early fire detection was developed by using a broadband infrared thermal light source and a dual-channel pyroelectric detector. This sensor system is mainly composed of a gas pretreatment part, an optical part, an electrical part and an upper computer monitoring part. Firstly, the detection principle of the sensor system was introduced, and then the absorption band of CO in the infrared region was selected by comparing the strength of absorption lines in different absorption bands and excluding the absorption interference of other gas molecules. Through the derivation of the optical matrix, the structure of the gas cell was designed and optimized, and the optical path of gas absorption reached 180 cm . The background noise fluctuation range of the phase-locked amplifier is 38.89 μV~43.23 μV, and the lowest detection limit is 0.15 μV. Finally, the performance of the sensor system was tested through related experiments. The results show that the measurement resolution is less than 2×10^-5 and the response time is 35~38 s. The concentration level of the 0×10^-6 CO standard gas sample was dynamically monitored for 80 minutes, and its concentration fluctuation range is -1.42×10^-5~1.51×10^-5. When the integration time is 0.25 s, the detection limit of the system is 1.54 ×10^-6, and when the integration time is 300 s, the detection limit of the system can reach 3.50×10^-7. Kalman filtering algorithm was used to improve the stability of the system. Similarly, the 0×10^-6 CO standard gas sample was dynamically monitored for 80 minutes. The results show that the relative error is reduced by 40.56 %, and when the integration time is 0.25 s, the detection limit is reduced to 3.60×10^-7. Finally, fire smoldering experiments of cotton, paper and wood were carried out to study the relationship between CO concentration and smoldering time. It is proved that the change of CO concentration can be used to detect the occurrence of fire. The experimental results show that the CO sensor system has a good early fire detection capability and wide application prospects.