AUV (Autonomous Underwater Vehicle) deck-back navigation method based on sonar map

The invention discloses an AUV (Autonomous Underwater Vehicle) deck-back navigation method based on a sonar map. The method comprises the following steps: (1) on the basis of an action distance of anAUV carried sonar, dividing an AUV working area in front of a seabed base station into an estimation guide area and a direct guide area, and scanning the AUV working area in front of the seabed base station so as to obtain a sonar map of seabed geomorphic features; (2) when an AUV goes back to a deck, enabling the AUV to sail to a depth same as that of the seabed base station, when the AUV is in the estimation guide area, enabling the AUV to scan the seabed geomorphic features in real time, matching feature points scanned at present with feature points in the sonar map, if the matching succeeds, modifying the sailing position of the AUV according to the sonar map, if the matching is failed, performing positioning navigation according to a navigation algorithm of the AUV self, when the AUVis in the direct guide are