A novel active pixels sensor (APS) based sun sensor based on a feature extraction and image correlation (FEIC) technique

A new feature extraction and image correlation (FEIC) algorithm is proposed and practised to improve the accuracy and reliability, the two key performances, of an APS sun sensor especially with multi-apertures and large field of view (FOV). A multi-aperture active pixel sensor ( APS) based sun sensor, which is composed of a micro electromechanical system (MEMS) mask with 36 apertures and a detector plane placed below the mask at a certain distance, exactly matches this FEIC algorithm. When the sun illuminates the sensor, an image of apertures is formed on the APS detector. Then the sun angles can be derived by analyzing the precise aperture image location on the detector via the FEIC algorithm. With this system, the centroid accuracy of the sun image can be achieved to 0.01 pixels (3 sigma), even when some missing apertures and some bad pixels appear on the detector because of aging of the devices and a harsh space environment. With the aforementioned features, the working life and application of a sun sensor will be extended.