ESA GNC Conference Papers Repository

Through 2009 and 2010 SELEX Galileo (I), BAE Systems (UK), CMOSIS (B), and with the support of Thales Alenia Space (F), together realised a system-on-chip digital sun sensor as a first example of implementation of the ESA Building Blocks strategy. The Miniature Sun Sensor prototype employs a custom-designed radiationtolerant CMOS image sensor/processor, immersed MEMS optics, and a miniature mechanical housing. The 12 x 12 mm sensor chip, made in the UMC 180 nm CIS process and with rad-hard IMEC DARE logic libraries, comprises of pixel array, readout circuits, ADCs, robust light-to-sun-coordinates processing, and TC/TM over SpaceWire or UART interfaces. The chip further integrates LVDS drivers, voltage regulators, power-on-reset, and a clock oscillator, requiring only one 5V supply and a clock crystal to make a complete low-power system. The pixels use '4T' buried diode technology with very low dark current, and are actually targeting future highaccuracy star tracker applications. The pinhole optics are fused with the sensor chips at the wafer level, prior to dicing. Prototypes of sensor chip, optics, and instrument were delivered in the second half of 2010. All components are fully functional and were characterised. Despite a bug in the ADC and an as of yet unfinished foundry process optimization for pixel performance, the requirements are broadly met. A complete manufacturing flow for the Sun Sensor on a Chip has been devised. It is the intention to evaluate and qualify this flow and the devices in a follow-up activity.