As for the question, in real life, the older sidewinders only used ir to track their targets, however, newer ir missiles use a dual seeker, i believe, which is ir and uv to track the targets, and will not lock on to the sun. Also, Some missiles can memorize an ir 'shape' of the target aircraft, so that a the large ball of ir energy from the sun won't fool its seeker.
Please correct me if i'm wrong! :music_whistling: