Star-Based Calibration of the Installation Between the Camera and Star Sensor of the Luojia 1-01 Satellite

Zhichao Guan,Jingyin Wang,Guo Zhang,Yonghua Jiang

doi:10.3390/rs11182081

Abstract

Ground control points (GCPs) are generally used to calibrate the installation between the camera and star sensor of a satellite in orbit and improve the geometric positioning accuracy of the satellite. However, the use of GCPs for high-frequency calibration is difficult, and it is particularly difficult to acquire accurate GCPs for the image of a nightlight satellite. In this study, we developed a camera-star sensor installation calibration method that eliminates the need for GCPs. In the proposed method, the camera and star sensor lenses are simultaneously pointed at the star, and the camera-star sensor installation is accurately calibrated by processing the star map obtained by the camera and star sensors. Reference data such as road network and Moon position data were used to verify the proposed method and evaluate its positioning accuracy. The results of the application of the method to the positioning of the Luojia 1-01 satellite indicated an accuracy within 800 m, which is comparable with that of the traditional method.

Highlights

The stress release that occurs during the launch of a satellite and the change in the physical environment when the satellite enters orbit alter the installation between the satellite’s camera and star sensor, resulting in reduced geometric positioning accuracy of images obtained by the satellite
In 2012, the Ziyuan 3-01 satellite was launched from China and achieved an image absolute positioning accuracy of 10 m (4.8 pixels, 2.1-m resolution) by ground control points (GCPs)-based method [8,9,10]
We developed a non-GCP method for the calibration of the camera-star sensor of the Luojia 1-01 nightlight satellite

Summary

Introduction

The stress release that occurs during the launch of a satellite and the change in the physical environment when the satellite enters orbit alter the installation between the satellite’s camera and star sensor, resulting in reduced geometric positioning accuracy of images obtained by the satellite. Multiple studies have been performed on in-orbit geometric calibration using ground control points (GCPs). This GCP-based calibration method acquires the precise determination of the parameters of the camera-star sensor installation, thereby improve the image positioning accuracy. Through a GCP-based method, the Advanced Land Observing Satellite (ALOS) launched from Japan in 2006 achieved an image absolute positioning accuracy of 8 m (3.2 pixels, 2.5 m resolution) [4,5,6]. In 2012, the Ziyuan 3-01 satellite was launched from China and achieved an image absolute positioning accuracy of 10 m (4.8 pixels, 2.1-m resolution) by GCP-based method [8,9,10].

Methods

Results

Conclusion