위성 영상센서 출력특성 교정용 MEMS 기반 흑체시스템에 관한 연구

Abstract

Spaceborne image sensors such as infrared (IR) detector have non-uniformity output characteristics owing to time elapses on/off operation during the mission period in orbit. Therefore, these image sensors require periodic calibration to correct the non-uniformity characteristics using a black body system to maintain the estimation accuracy with respect to measurement objects and image quality of the observation satellite. The main objectives of a black body system for image sensor calibration are estimating a representative surface temperature from an image sensor and providing a uniform temperature distribution at various reference temperatures from a black body surface. For example, Oh et al. developed an on-board black body system that can provide temperature calibration from low to high temperature, while calibrating the non-uniformity characteristics to an IR detector. However, the function of the on-board black body system was limited to calibrating the non-uniformity characteristics, such that the reference temperature information that can perform is very limited. In addition, the on-board black body system requires a complex thermal design to provide reliable, accurate temperature estimations. It was essential to consider a thermal conduction path or thermal mass at low temperature and additional heaters at high temperature for providing low- and high-temperature information. These technical approaches might increase the complexity of the thermal design and lower its reliability. To overcome the above mentioned drawbacks of the conventional black body system, a MEMS-based black body system using a thermoelectric device was proposed in this paper. The MEMS-based black body system has advantages, such as lightweight, low power, and high accuracy that makes it easier to estimate the representative surface temperature of the black body. In addition, it can obtain high-temperature uniform information at various reference temperatures, from low- to high-temperature consumption, compared with conventional systems. In addition, applying a radiator of aluminum having high conductivity for transport of the residual heat and thermal conduction path from the black body to the deep space. The feasibility of the proposed MEMS-based black body system was validated through the thermal analysis.