same meaning, "correct"... but "精确" is much more heavily than "准确" for example, when someone ask you how to go somewhere, you just need to give him a "correct direction" "正确方向" when you doing a experimentin in a lab, you should write down the "correct data" "精确数据"

simply,"在" means "at, in, from "etc. this kind of preposition in english, and "再" means "again", pronunciation are same, but the meaning are much more different