Underwater acoustic asynchronous distance measurement method

The invention provides an underwater acoustic asynchronous distance measurement method, and belongs to the technical field of underwater acoustic distance measurement. The method comprises the following steps of: (1) measuring sound velocity and depth in the ocean by using a sound velocity gradiometer at a transmitting end, and establishing an equivalent layered sound velocity profile by using a gradient judgment method; (2) in combination with acoustic parameters such as a sound velocity profile, establishing sound propagation time tables under different horizontal distance under different emission depths and different receiving depths by utilizing a rapid sound ray tracking method; (3) measuring the depths of the transmitting end and the receiving end by using a depth sensor, and measuring the acoustic propagation time of the transmitting end and the receiving end by using an underwater acoustic asynchronous distance measurement mode; and (4) in the sound propagation time table, preliminarily estimating the horizontal distance by using a table look-up method, and correcting the horizontal distance by combining a rapid sound ray tracking method and a linear interpolation method soas to obtain the distance between the transmitting end and the receiving end. According to the method, the speed of searching the intrinsic sound rays by using the ray acoustic model is increased, and the calculation amount is reduced.