In-orbit absolute radiation calibration method and system for optical remote satellite

Abstract

The invention discloses an in-orbit absolute radiation calibration method and system for an optical remote satellite. The method comprises the following steps: acquiring the field information of a calibration field; determining the high-spectrum atmospheric transmittance of the solar path and that of the remote satellite observing path by using a radiation transmission model; determining the entrance pupil radiance reflected by a reflection point source target to the remote satellite according to the high-spectrum atmospheric transmittance and reflection point source parameters of the solar path and the remote satellite observing path; obtaining the radiation response value of the remote satellite to each unit of the reflection point source target; according to the entrance pupil radiancereflected by the reflection point source target to the remote satellite and the radiation response value of the remote satellite to each unit of the reflection point source target, determining the in-orbit absolute radiation calibration coefficient of the optical remote satellite based on the reflection point source by using the calibration equation of the remote satellite and completing the calibration. The in-orbit absolute radiation calibration method and system can realize high-frequency, high-precision, operational and normalized mobile calibration of the high-resolution optical remote satellite in the full dynamic range.

Description

technical field [0001] The invention relates to the field of optical remote sensing, in particular to an on-orbit absolute radiation calibration method and system for optical remote sensing satellites. Background technique [0002] Optical remote sensing data is not only used in the field of qualitative or semi-quantitative description of the basic characteristics of ground objects, but also goes deep into the field of quantitative interpretation of geophysical parameters and the evolution of the earth's environmental system. At the same time, the technical capabilities of refined quantitative remote sensing are also improved Rely on the support of calibration technology. Although the optical remote sensing satellite payload requires strict laboratory calibration before launch, due to factors such as satellite launch vibration and acceleration, in-orbit space environment, and aging of electronic components, the performance of the remote sensor will inevitably decay to varyin...

AI Technical Summary

Problems solved by technology

Whether the on-board calibration adopts the built-in standard lamp and integrating sphere or the solar diffuser method, the ground laboratory radiation reference is used as the on-board calibration reference, and there is a problem of tracing the source to the international unit, and the impact of the satellite launch process There is no effective monitoring method for influencing parameters such as acceleration and acceleration, and it will completely rely on its own stability to ensure its expected accuracy after launch.

The radiation calibration of operational remote sensing satellites is mainly based on site substitution calibration. At present, calibration methods based on large-area uniform radiance targets such as deserts, dry lake beds, ice and snow, etc. of tens or even hundreds of square kilometers have been developed internationally. Although it has achieved good application results, it is a single-point (radiance) calibration method, and there are certain differences in the characteristics and applicability of various algorithms.

Moreover, there are few and single sites, which are easily restricted by factors such as site location and weather conditions, resulting in long satellite calibration cycles, few opportunities, and low efficiency.

In view of the rapid development of high-resolution satellites in recent years, the use of large-area (thousands or even tens of thousands of square meters) artificial targets with excellent optical characteristics as a radiance reference target has been proposed internationally, and the radiation determination of the full dynamic range of spaceborne optical remote sensors has been realized. However, the traditional radiation calibration method centered on the calculation of radiation transfer needs to make assumptions about aerosol characteristics, atmospheric point spread function, and ambient reflectivity. The calculation error caused by the assumption is also high. At the same time, a large amount of target transportation, layout, and testing consume a lot of manpower, material and financial resources. It is not suitable for automatic calibration and high-frequency calibration of optical remote sensing satellites.

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