Remote sensing camera on-orbit geometric calibration method based on fixed star trajectory

Abstract

The invention discloses a remote sensing camera on-orbit geometric calibration method based on a fixed star trajectory. The method comprises the following steps: (1) acquiring a star map; (2) acquiring a high-precision fixed star position by adopting a centroid extraction algorithm; (3) performing curve fitting on the fixed star position and removing abnormal points to obtain a fixed star track; (4) establishing a camera strict imaging geometric positioning model based on the collinear equation and the generalized pointing angle model; (5) calculating object space vectors of the fixed star track points at different moments according to the right ascension and declination and ephemeris data of the fixed star; and (6) resolving internal and external calibration parameters based on space resection and a least square method to achieve high-precision geometric calibration. According to the method, when the number of fixed stars in the field of view is small, on-orbit geometric calibration of the remote sensing camera can be achieved by utilizing the track of the fixed stars sliding over the image plane, the problem that geometric positioning precision is affected due to the fact that ground control points are difficult to obtain due to cloud shielding is effectively solved, and the method is small in calculated amount, high in precision and high in robustness.

Description

technical field [0001] The invention mainly relates to the technical field of geometric positioning of remote sensing satellites, in particular to an on-orbit geometric calibration method of a geostationary orbit remote sensing camera. Background technique [0002] Remote sensing cameras are usually calibrated on the ground before launch, including the calibration of the internal distortion of the camera and the calibration of the installation relationship of the camera relative to the attitude control system. However, due to the complex structure of the camera and the large size of the optical parts, the acceleration and shock vibrations endured during the launch process, the changes in the surrounding environment during orbital operation, and the thermal radiation from the sun will make each parameter or model deviate from the calibration value on the ground. It will affect the high-precision target positioning, so the on-orbit calibration of the spaceborne camera is requi...

AI Technical Summary

Problems solved by technology

When the remote sensing camera performs geometric calibration based on the ground control points, the geometric calibration field or DEM / DOM products are generally used to obtain the ground control points. Influenced by various factors, when the remote sensing camera performs geometric calibration based on star observation, it often needs to observe a large number of stars in the field of view of the camera, so when the camera only observes a small number of stars, the calibration method is limited

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