Abstract: The measurement accuracy of Sun Sensor is mainly influenced by earth albedo. In this paper, a model about energy attenuation for sunlight incident upon CCD Sun Sensor in large angle is proposed. Through computing peak value of earth albedo irradiance, the influence is correlated with sunlight’s incident angle in theory. For instance, the irradiance produced by earth albedo is comparable to that of the Sun, when the Sun appears in the edge of field of view of CCD Sun Sensor and earth albedo appears in the worst condition. Finally a method about the improvement of structural parameter of Sun Sensor to decrease the influence of earth albedo on Sun Sensor is presented.

Key words: CCD Sun Sensor, earth albedo, radiant intensity, energy attenuation, ratio of transmission