On-orbit geometric calibration method for high-orbit area array optical satellites considering atmospheric refraction correction

Abstract

The invention provides a high orbit area array optical satellite in orbit geometry calibration method considering atmospheric refraction rectifications; the method comprises the following steps: usingpolynomial fitting probe directional angles to build an internal calibration model, parsing influence rules on the image geometry precision by the atmospheric refraction, building an external calibration model considering the atmospheric refraction rectification, and introducing the internal and external calibration models into a strict geometry imaging model so as to build a high orbit optical satellite in orbit geometry calibration model; parsing internal and external calibration parameter initial values according to sub-satellite point images; using the parsed internal calibration parameter as the true-value, using images obtained by different sequence imaging angles, and parsing the external calibration parameter according to the external calibration parameter initial value. In the high orbit optical satellite in orbit geometry calibration process, the method can fully consider the influences on the imaging geometry precision by the atmospheric refraction, thus building the more strict in orbit geometry calibration model, and obviously improving the high orbit optical satellite image direct geometry positioning precision.

Description

technical field [0001] The invention belongs to the field of remote sensing image processing, and relates to an on-orbit geometric calibration method for high-orbit area array optical satellites in consideration of atmospheric refraction correction. Background technique [0002] On-orbit geometric calibration is an important part of optical satellite geometric preprocessing, and it is an effective means to improve the direct geometric positioning accuracy of images and improve the relative geometric distortion between images. On-orbit geometric calibration is generally completed within a few months after the satellite is successfully in orbit. The parameters that affect the geometric accuracy of the image are calibrated by using high-precision ground reference data. At this stage, the commonly used on-orbit geometric calibration method is used to calibrate The parameters are mainly divided into two types: internal parameters and external parameters. The internal parameters a...

AI Technical Summary

Problems solved by technology

This method of calibrating internal parameters and camera installation angles has been widely used in the on-orbit geometric calibration of many low-orbit satellites, but this method is not suitable for high-orbit optical satellites. This inapplicability is mainly manifested in the traditional method The influence of atmospheric refraction on the positioning accuracy of the image is not considered. In the traditional method, the external calibration parameters mainly absorb the installation angle error, attitude drift error and GPS eccentricity distortion, and the internal calibration parameters compensate for errors such as CCD deformation and lens distortion. High calibration accuracy can be achieved without considering the influence of atmospheric refraction, mainly because for low-orbit satellites, the orbit altitude is low, so the pressure and temperature difference between the ground and the altitude of the satellite is small, so the atmospheric refraction However, for high-orbit satellites, the pressure of the ground and the environment where the satellite is located is relatively high, so the difference in atmospheric refractive index is relatively large, which will cause light to be refracted during the propagation process. In addition, due to The altitude of the orbit is high, and this refraction will be amplified during the propagation process, resulting in a large positioning error on the ground

Images