System and method for detecting position of underwater vehicle

The position detection system includes a pressure sensor that detects the vertical position of an underwater vehicle, a range sensor unit that detects the relative distances of the underwater vehicle from its surrounding structures; a measurement image acquisition unit that acquires a measurement image of the horizontal plane, an image storage unit that stores images, an image selector that selects one of the stored images that corresponds to the horizontal plane in which the relative distances have been detected, a corresponding-area identification unit that identifies the area in the selected image that corresponds to the measurement image by performing map matching, and a horizontal position calculator that identifies, the pixel that corresponds to the position at which the relative distances have been detected and calculates the horizontal position of the underwater vehicle.