The device used for locating the position and distance of an object using ultrasound is called Sonar. It stands for Sound Navigation and Ranging. Sonar works by emitting ultrasonic waves (sound waves with frequency above 20,000 Hz) and then detecting the echo reflected back from an object. The distance to the object is calculated using the formula:

$d=\frac{v\times t}{2}$

where $d$ is the distance, $v$ is the speed of sound in the medium, and $t$ is the time taken for the echo to return. This principle is used in submarines, fish finders, and medical imaging.

Final Answer: Sonar