All these could have AT after them if you wanted.
1. Argo - Named for the famed ship of mythology on which Jason sailed in search of the fabled Golden Fleece, fitting as well since this is a land / water detector. Argo AT has a nice sounding name and my personal favorite.
2. Dorado -Historical connotations in the search for El Dorado, and literally translates to Golden. Deteknix Dorado, or Deteknix Dorado AT has a good ring to it.
3. Alicanto - Bird of the desert of Atacama, from Chilean mythology, which brings luck to any miner who sees it. The bird feeds on gold and silver. Seems particularly fitting, and again, Alicanto AT has a good ring to it.