The Turkish spelling is 'Alaca Höyük'.The bicephalous (two-headed) eagle was the main heraldic symbol of the Hittites.   A quick Google search of the internet will lead you to numerous web sites that cite as a fact that the Hittites were the first to use this symbol, and that other uses of the two-headed eagle (e.g. Byzantium, Russia, Germany and Albania) derive either directly or indirectly from the Hittite version.   One even claims that the Roman (single-headed) eagle was based on it.   I'm not qualified to comment on the truth of any of this, but it is all fascinating.

This is the central scene in Chamber A. There are many figures either side of this scene forming two processions of gods that lead up to this central meeting of Teshub and Hebat. The figures in this picture are, left to right, as follows. First is probably Teshub's brother, standing astride two mountain peaks. Next is Teshub, the weather god, who is bearded and wears a tall, conical hat and a short-skirted tunic; he stands on the shoulders of two mountain gods (probably Namni and Hazzi). Facing him is the sun goddess Hebat wearing a fluted, cylindrical hat and a blouse and long skirt; she stands on the back of a large feline, which is in turn standing on mountain peaks. Behind her is Sharrumma, the son of Teshub and Hebat. He is the only male figure in the procession behind Hebat. He too stands and the back of a feline that is standing on mountain peaks. Next come two female figures: the first is identified as Alanzu, the daughter of Teshub and Hebat; the second might be their granddaughter. They are dressed similarly to Hebat, but the clothes aren't as full and flowing as hers; they are supported by a double headed eagle with wings spread.

The King Tudhaliya IV is depicted in the protective embrace of the much taller god Sharrumma, his patron. The king is dressed in long robes and a scull cap and is carrying a long wand, curled at the bottom (a lituus). The god is wearing a short skirted tunic with a belt and a tall conical hat with many horns on it. Both of them have pointed shoes that curl up at the toe and a short sword, the hilts visible at their waists. Behind Sharrumma's hat is a cartouche, in Hittite heiroglyphics, giving the king's name and title.