On-Orbit Geometric Calibration from the Relative Motion of Stars for Geostationary Cameras

Area of Science:

• Remote Sensing
• Astrophysics
• Optical Engineering

Background:

• On-orbit calibration of remote sensing cameras is crucial for geometric accuracy.
• Traditional methods using ground control points (GCPs) or stars face challenges like cloud cover and insufficient star data, especially for geostationary satellites.
• Vibrations and thermal shocks during launch can displace camera positioning models.

Purpose of the Study:

• To develop a novel on-orbit geometric calibration method for geostationary cameras.
• To improve the geometric accuracy of remote sensing imagery.
• To overcome the limitations of conventional calibration techniques.

Main Methods:

• Constructing a geometric calibration model based on the optical system.
• Analyzing the relative motion transformation of observed stars.
• Utilizing stellar trajectories and auxiliary ephemeris for iterative correction of calibration parameters.

Main Results:

• The proposed method achieved positioning error correction within ±2.35 pixels on a geostationary satellite.
• Demonstrated effective camera calibration and improved positioning accuracy.
• Successfully avoided cloud cover influence and reduced dependence on the number of observed stars.

Conclusions:

• The novel on-orbit geometric calibration method using relative star motion is effective for geostationary cameras.
• This approach enhances geometric accuracy and overcomes limitations of existing methods.
• It provides a robust solution for recalibrating remote sensing cameras in orbit.