利用SBDART软件包计算了不同地球大气系统下2.5~5μm波段范围内的大气透过率和地球大气背景红外辐射光谱。计算目标与地球大气背景之间的信噪比,并据此分析了地球大气系统对红外目标探测的影响。结果表明:当目标位于卷云之上时,在2.5~3μm波段与4~4.5μm波段信噪比较大,信噪比随着目标高度的升高而增大,易于探测;当目标处于卷云以下时,卷云对红外信号有较强的吸收作用,光学厚度对信噪比影响较大,粒子尺度对信噪比影响不大,卷云厚度越大,信噪比越小。 The SBDART software package was used to calculate the atmospheric transmittance and the Earth’s atmospheric background infrared radiation spectrum in the 2.5-5μm band under different Earth’s atmospheric systems. The signal-to-noise ratio between the target and the earth’s atmosphere background is calculated, and the influence of the earth’s atmosphere system on the infrared target detection is analyzed accordingly. The results show that when the target is located above the cirrus, the signal-to-noise ratio is large in the 2.5-3μm and 4-4.5μm bands, and the signal-noise ratio increases as the target height increases, making it easy to detect. When the target is in the roll Clouds below the cloud of infrared signals have a strong absorption, the optical thickness of the greater impact on the signal to noise ratio, the particle size has little effect on the signal to noise ratio, the greater the thickness of the cirrus, the smaller the signal to noise ratio.