Butt joint recovery method and system for autonomous underwater vehicle

The invention provides a docking recovery method and system for an autonomous underwater vehicle, and the method comprises the steps: obtaining a three-dimensional position, measured by an ultra-short baseline positioning system, of the autonomous underwater vehicle, and the three-dimensional position comprises a plane position and depth; under the condition that the depth does not accord with the preset range, constructing a state transition equation by taking the plane position and the speed of the autonomous underwater vehicle as a state quantity and a control quantity respectively, and constructing an observation equation by taking the distance between the autonomous underwater vehicle and the docking station as an observed quantity; an unscented Kalman filtering algorithm with fading factors is adopted, and suggested distribution in a particle filtering algorithm is generated based on the state transition equation and the observation equation; a particle filter algorithm is adopted, and plane position es