The impact of atmospheric content changes on space-based infrared detection for aerial targets

Space-based infrared technology has the potential to detect aerial targets globally, for which strong atmospheric absorption of the background radiometric signal provides spectral detection windows. However, the atmospheric content varies in time and space, affecting its attenuation of the background. It is therefore necessary to assess the impact of the variation in the atmospheric content of absorption gas on the target detection. Based on the aerial target space-based observation characteristics model, the target radiation contribution ratio and the target-background contrast were calculated for different atmospheric contents with reference to the typical atmospheric profiles. The variation of the target-background relative differences due to changes in gas content was discussed. Furthermore, the range of change in the target-background contrast and signal-to-noise ratio(LSNR) for different atmospheric contents was calculated, considering instrument response characteristics. The effect of atmospheric content and full width at half maximum (FWHM) variation on the stability of the target-background relative relationship was analyzed. The findings highlight that the target radiation contribution ratio and the target-background contrast are more significantly affected by changes in water vapor, while changes in carbon dioxide concentration have little effect due to its large content base. Spectral bands where water vapor and carbon dioxide interact can reduce the effects of water vapor changes, but require narrow FWHM. But the too narrow FWHM can lead to changes in the target-background relative relationship and reduce its stability due to the influence of instrument noise. This research helps to understand the impact of changes in atmospheric condition on space-based infrared detection of aerial targets and the challenges faced in developing detection algorithms.