High-precision CubeSat sun sensor coupled with infrared Earth horizon detector

Abstract

This paper presents a novel miniature module of orientation sensors for CubeSat nanosatellites. A high-precision sun sensor and a detector of the Earth horizon are located in one small module body. A two-axis digital sun sensor built into the orientation module is based on the registration of the sunspot formed on the matrix CMOS image sensor when the sun's rays pass through a pinhole in the front mask. A commercially available miniature array of infrared thermometers is used as the Earth horizon sensor. The paper is mainly devoted to the development of the sun sensor. For laboratory tests, a prototype of the orientation module was developed. Laboratory tests and sun sensor calibration confirmed the sun sensor field of view of 120° and made it possible to determine its angular resolution of ±0.015°. The final accuracy of determining the direction to the Sun by the sensor that was calibrated using the existing experimental setup is ±0.15° with 95% confidence. It is possible to improve the accuracy of the sun sensor by improving the experimental setup for its calibration.