The Concept Design of a Fore-field Camera for the Intelligent Hyperspectral Remote Sensing Satellite

摘要

Hyperspectral remote sensing provides continuous spectral information of ground surface, demonstrating special ability in fields such as classification, target identification and quantitative estimation of land cover. However, the radiometric dynamic range cannot be adjusted according the actual ground surface condition and the atmosphere condition. Recently, with the rapid development of on-board processing and electronic techniques, it seems possible to adjust the radiometric range according to the actual imaging condition by setting a multiple-bands fore-field sensor. In this paper, we give a detailed concept design and working mode of the fore-field sensor, such as the fore viewing angle, spectral bands and radiometric dynamic range adjustment model. The fore-viewing angle is set to leave enough time for the on-board device to update the radiometric dynamic range for the hyperspectral sensor. We give some results of inclined angle by considering the fore-field camera acquiring image and response time for main camera adjusting its image status. The minimum 5 spectral bands were carefully chosen to identify clouds, to estimate aerosol parameters and water vapor. The bands include 0.49 μm, 0.66 μm, 0.87 μm, 0.94 μm and 2.1 μm. The first two bands and last band were used to estimate the aerosol model and aerosol optical depth. The second and the fourth bands were applied to identify clouds. And the third and four bands were combined to estimate the water vapor. Then the minimum and maximum radiances could be approximately estimated by these parameters. We focus the simulation in the range of 0.4-1.4 μm by selecting spectrum from dry and green vegetation. Two bands of radiance at wavelength of 0.66 μm and 0.87 μm is enough to predict the dynamic range for the spectral range of 0.4-1.4 μm.