Visible Blind Quadrant Sun Position Sensor in a Silicon Carbide Technology

In this paper, we present a quadrant sun position sensor microsystem device in a silicon carbide technology that operates in a field-of-view of ±33° and reaches a mean error of 1.9° in this range. This will allow, for the first time, an inherently visible blind sun position sensor in a CMOS compatible technology. Opto-electronic integration of the photodetectors and CMOS readout circuitry on-chip is vital to compete with the performance of silicon state-of-the-art and for the concept to be adopted by industry, which is where previous implementations of visible blind sun sensors are lacking.

Introduction

The sun position sensor is an attitude sensor that is able to provide information on the direction towards the Sun. It is a vital device for satellite attitude control in outer space and is continuously subjected to further improvements. Silicon state-of-the-art commercial sun position sensors suffer from an inherent sensitivity to the albedo, which is the visible light reflected by the Earth. This undesired sensitivity is directly related the semiconductor bandgap, as this determines the photodetector spectral response. The importance of visible blindness for sun position sensors was previously recognized and implemented in an InGaAs technology [1] and a GaN-on-sapphire technology [2] to target spectral bands in IR and UV respectively. Both of the previous implementations, as well as this work, rely on the collimating sun sensor architecture [3].