The paper describes the results of testing experiments for solving problems of thermometry and positioning of an autonomous underwater vehicle (AUV) in the Korean Strait in a shallow sea with less than 10 m of water. The studies were conducted on acoustic tracks up to 615 m long, sensed with complex phase shift keyed signals with a centeral frequency of 2500 Hz. Under field experiment conditions, it was shown that the resolution of the structure of pulse responses makes it possible to sense temperature changes less than one degree and to secure positioning of the AUV with an accuracy better than 1 m when operating in the near bottom layer.