The invention discloses an
installation error calibration method based on Student's T distribution and variational Bayes, which comprises the following steps: firstly, constructing an
installation error calibration geometric model of an SINS / USBL
system, defining coordinate systems, establishing an attitude
transfer matrix between the coordinate systems, and designing a state equation and a measurement equation by taking
installation error angles in three directions as state variables; time updating and measurement updating are carried out based on a Kalman filtering framework; the method comprises the following steps of: embedding Student's T distribution into a variational
Bayesian filtering framework, alternately updating distribution parameters of a
state variable, a
noise covariance and an auxiliary variable through a variational iterative optimization process, maximizing a variational lower bound until convergence, and outputting an optimized installation error angle estimated value. According to the method, acoustic measurement
noise is modeled by using the heavy
tail characteristic of the SINS / USBL combined
system, the interference of outliers on installation error angle
estimation is remarkably inhibited, the positioning accuracy of the SINS / USBL combined
system in a complex
underwater environment can be effectively improved, and the calibration robustness is enhanced.