Advent of the IBIS as the digital sunsensor for the future

Abstract

For many years there have been attempts to eliminate the earth albedo sensitivity for Sunsensors. This is best done through development of a true digital Sunsensor. The best known digital Sunsensor was designed (and patented) by Adcole back in the 1970's only to be followed by the Leonardo smart digital Sunsensor and a small digital Sunsensor developed by Sinclair interplanetary some 30 years later. The first two sensors are relatively large and expensive, whereas the later is small and affordable but lacks the required radiation tolerance and quality level required for longer duration ESA missions. Although TNO attempted to develop a small but highly reliable Sunsensor between 2004 and 2010, this development did not lead further than the prototype called mini-DSS. From this TNO research and developments it became apparent that the detector technology and detection principle used are key to delivering the desired properties: high reliability, low cost, small form factor and low power consumption. While Leonardo stopped the development of a small digital Sunsensor in 2017, Lens R&D is now developing such a device in frame of an ESA Artes 5.1 contract signed in April 2018. Based on insights developed during the TNO mini/micro-DSS program and a new operating principle, the Intensity Based Images Sensing (IBIS) principle is expected to lead to a producible sensor that is low power, highly reliable and cost effective. The dedicated imager (dubbed IPS) required for the demonstrator to be built within the framework will be designed by SystematIC Design and is expected to show a very low power consumption and low operation voltage. These properties are important in order to allow for further design optimizations related to potential autonomous powering or power over data applications. The presentation will focus on the status of the Artes program design considerations for the IBIS sensor and the optical design of the sensor, which is core to providing a highly reliable but cost-effective sensor.