IBIS Advanced Technology for SmallSATS

For many years, ESA has been involved in attempts to develop a commercially attractive radiation hardened true digital Sunsensor. Although both Galileo Avionica (IT) (now Leonardo) and TNO (NL) developed a sensor based on standard active pixel sensors (APS) none of these products became commercially successful. Although TNO started the development of a single chip true digital Sunsensor in 2004 and a prototype was successfully tested in 2011,[1] [2] the product was neither radiation hardened nor optimized for volume production. Development of this prototype into a real sensor was however never completed. Although both a digital output and albedo sensitivity for a Sunsensor are two properties high on the Wishlist of many satellite builders, a single chip true digital Sunsensor has never been built before. This is why ESA started an ARTES program in cooperation with Lens R&D B.V. and Systematic Design B.V. that was supposed to lead to a cost-effective single chip radiation hardened true digital Sunsensor. Advantages of such a sensor are: Minimum SWaP (Size, Weight and Power) True radiation hardened electronics due to the use of special design techniques and radiation hard cell designs High reliability due to the use of a minimum number of external components and re-use of an already proven mechanical concept High repeatability and yield due to the use of modern chip technology (0.18μm XFAB) Combined with an optimization for volume manufacturing (as used by Lens R&D B.V. for the production of their BiSon and MAUS Sunsensors), the new IBIS sensor (Intensity Based Image sensor) is expected to provide the most cost-effective solution for high reliability Sun sensing available on the market once completed. As the sensor will be facing the Sun directly in vacuum, a lot of emphasis is given to the reduction of the power consumption. Performance predictions as performed during the design of the chip showed an estimated power consumption of less than 130mW for the entire sensor. Initial measurements however show a power consumption of only 33mW which is significantly lower and a pleasant surprise Along with measurements that have shown the power consumption to be significantly lower than expected, the majority of the functionality could be proven on the first prototypes. A limited number of design errors will still need fixing before a fully functional sensor can be offered to the market. Next to this a significant amount of radiation testing will need to be done before the requested 15 years in GEO can be guaranteed. Despite a development trajectory of more than 20 Years, the sensor will however still be unique and provide a solution long sought for.