The invention discloses an initial alignment method for a movable base of an
underwater vehicle based on multi-navigation-
system Kalman filtering, and the method comprises the steps: constructing N navigation systems which are uniformly distributed in the
azimuth, enabling the included angles between the x axes of the N navigation systems and the x axis of an n
system to be gradually increased, and splitting the three-dimensional attitude misalignment angle of an STEKF
algorithm model on each
navigation system; independently operating the STEKF
algorithm on each
navigation system to obtain an initial course angle estimated value of the carrier in each
navigation system; and according to the initial course angle estimated value in each navigation
system, obtaining an optimal navigation system by using a preset screening rule, and obtaining a final alignment result corresponding to the optimal navigation system. According to the method, a plurality of navigation systems covering all-directional angles are constructed, a large
azimuth misalignment angle problem is converted into a small misalignment angle
estimation problem which can be accurately processed by a
linear model, and an optimal result is selected from a parallel filter based on three-dimensional attitude misalignment angle splitting; and the problem that the
estimation precision of state transformation Kalman filtering and
nonlinear filtering is reduced under the condition of a large misalignment angle can be solved.