Modelling and Testing of Two-Dimensional Sun-Sensors

This paper presents the modelling, algorithm development, and laboratory testing of a two-axis digital sun-sensor. The basis for our modelling is the Sinclair interplanetary SS-256, a sensor that employs a single, linear array to provide two-axis measurements of the sun-vector. The detector illumination simulation uses a Fresnel diffraction model to synthesize the detector image. This image agrees with actual sensor images to within about 4% (rms). Algorithm studies contrast the performance of existing peak-detection routines with centroiding and simple parametric algorithms. Laboratory studies confirm that these modified algorithms can provide a three-fold performance improvement over the baseline sensor processing.