探测天顶角与太阳天顶角对卫星红外探测的影响

Effect of the Detective Zenith Angle and the Solar Zenith Angle on Satellite-borne Infrared Detection

为了分析不同探测环境对卫星红外探测的影响，推导了倾斜探测路径下目标与背景在探测器入瞳处的辐照度对比度计算公式。计算了目标在海天背景下不同温度、不同高度、不同太阳天顶角、不同探测天顶角条件下，目标与背景在0.75～14μm波段的红外单色辐射照度对比度。分析指出：太阳天顶角对红外探测的影响主要在2.7μm以下波段，探测波长大于2.7μm可不考虑太阳的影响。目标在5 km以下、探测天顶角在60°以上继续增加时，探测波段变窄，不可探频段增宽；目标在10 km 以上，探测天顶角变化对探测影响很小。这些结论可用于指导卫星红外探测波段选择与探测结果分析。

In order to analyze the effect of various detective situations on the satellite-borne infrared detection, the irradiance contrast formula of target and background at the satellite-borne infrared detector under acclivous detective path is derived. If the target is in both sea and atmosphere backgrounds, the monochrome irradiance contrast of the target and the background at 0.75-14μm waveband is calculated with the target at various temperatures and altitudes under various detective zenith angles and various solar zenith angles. The analysis conclusions are as follows：the effect of the solar zenith angle is mainly within the wavebands shorter than the wavelength of 2.7μm, and it can be ignored when the wavelength is longer than 2.7μm. When the target altitude is lower than 5 km and the detective zenith angle is above 60°and keeps on increasing, the optimum detective wavebands narrow down and the un-detective wavebands widen. When the target altitude is higher than 10 km, the effect of the detective zenith angle is small for infrared detection. These conclusions can be used to guide the satellite-borne infrared detective waveband selection and the result analysis.