An autonomous low-power high-resolution micro-digital sun sensor

Abstract

Micro-Digital Sun Sensor (μDSS) is a sun detector which senses the respective angle between a satellite and the sun. It is composed of a solar cell power supply, a RF communication block and a CMOS Image Sensor (CIS) chip, which is called APS+. The paper describes the implementation of a prototype of the μDSS APS+ processed in a standard 0.18μm CMOS process. The μDSS is applied for micro or nano satellites. Power consumption is a very rigid specification in this kind of application, thus the APS+ is optimized for low power consumption. This character is realized by a specific pixel design which implements profiling and windowing during the detection process. The profiling is completely fast and power efficiently by a "Winner Take ALL (WTA)" principle. The measurement results shows that the APS+ achieves a reduction of power consumption by more than a factor 10 compared to state of-the-art. Besides the low power consumption, the APS+ also proposes a quadruple sampling method which improves thermal noise with 3-T Active Pixel image Sensor (APS) structure.