Method and system for locating underwater vehicle on basis of global navigation satellite system (GNSS) satellite

The invention discloses a method and a system for locating an underwater vehicle on basis of a global navigation satellite system (GNSS) satellite, wherein a plurality of locating buoys are additionally arranged on the water and carry GNSS receivers and underwater sound responders. The underwater vehicle carries the underwater sound responder. The locating buoys utilize a GNSS satellite location technique to complete self location and time service. When the underwater vehicle is needed to be located, the inquiry signal which is sent out by the underwater sound responder on the underwater vehicle is responded by the underwater responders on the locating buoys and then returns to the underwater responder. When the underwater vehicle simultaneously obtains at least 3 locating buoys which are distributed on the water and a certain resolving relation, the three-dimensional location coordinates of the underwater vehicle can be finally obtained. An underwater sound relative locating technology can be utilized to expand the GNSS water level precision locating capability towards underwater, so the underwater vehicle can directly obtain the self geodetic longitude and latitude coordinates at an operating submerged depth, and the locating precision is enabled to be at the same order of the GNSS water level locating precision.