Digital Sun Sensor Multi-Spot Operation

• Main Authors: Michele Grassi, Giancarlo Rufino
• Format: Article
• Language: English
• Published: MDPI AG 2012-11-01
• Series: Sensors
• Subjects: sun sensor; APS; centroiding; attitude determination; image processing
• Online Access: http://www.mdpi.com/1424-8220/12/12/16451

The operation and test of a multi-spot digital sun sensor for precise sun-line determination is described. The image forming system consists of an opaque mask with multiple pinhole apertures producing multiple, simultaneous, spot-like images of the sun on the focal plane. The sun-line precision can be improved by averaging multiple simultaneous measures. Nevertheless, the sensor operation on a wide field of view requires acquiring and processing images in which the number of sun spots and the related intensity level are largely variable. To this end, a reliable and robust image acquisition procedure based on a variable shutter time has been considered as well as a calibration function exploiting also the knowledge of the sun-spot array size. Main focus of the present paper is the experimental validation of the wide field of view operation of the sensor by using a sensor prototype and a laboratory test facility. Results demonstrate that it is possible to keep high measurement precision also for large off-boresight angles.