柯林斯詞典echo sounder 1. N a navigation and position-finding device that determines depth by measuring the time taken for a pulse of high-frequency sound to reach the sea bed or a submerged object and for the echo to return 回聲測深儀 返回 echo sounder劍橋詞典a piece of equipment , especially on a ship , that uses sound waves to discover water depth or the position of an object in the water (尤指船載)回聲探測器 返回 echo sounder