Add to ORKGThis paper deals with the digital micro sun sensor under development at the university of Naples, Italy. It will be validated on board of the Italian Space Agency satellite MIOsat, scheduled for launch in 2011. The micro sun sensor is one of the technology payloads of MIOsat. Peculiar aspects of the sensor are presented in the paper: innovative hardware configuration for improved precision through multiple simultaneous measurements, neural calibration function, COTS-based design. Finally, the results of a preliminary ground test campaign carried out on a sensor prototype using a properly designed laboratory test facility are presented. Performance improvement is demonstrated to be in the order of 1 arcsecond