Micro-sun-sensor performance validation in ground-reproduced orbital conditions

This papers deals with the large-FOV, micro-sun-sensor under development at the University of Naples. The sensor exploits a multi-hole mask to measure the sun line with high precision. Nevertheless, multi-spot operation exhibits failures near FOV borders, due to the uncertainty in the number of spots that can be reli-ably acquired. After a short description of the sensor concept, hardware model, and laboratory test equipment, this paper focuses on the latest upgrades of the sensor operation mode, aimed at getting reliable operation ability and improved precision over a wider FOV (at least 90x80 deg). Specifically, an original tech-nique is implemented in which the sensor shutter-time is automatically adapted based on detected image intensity to improve precision near FOV borders. Re-sults of the validation and performance assessment campaign of the upgraded operation mode executed with the ground facility are presented. In these tests sensor precision is characterized as a function of the separation of the illumina-tion direction from FOV centre, showing that the upgraded operation mode al-lows getting high precision (about 0.001°) also near FOV borders.