The invention provides a multi-
modal fusion and
semantic enhancement train positioning method and
system, and belongs to the technical field of
rail transit, and the method comprises the steps: carrying out the time-space alignment of data, obtaining a dense
point cloud, constructing a dense semantic
point cloud, and dynamically estimating the confidence coefficient weight of each type of sensors; a set residual error and a Manhattan structure constraint residual error of a plane are constructed,
laser radar point cloud parameters are obtained, and
visual projection constraints are constructed at the same time; constructing a comprehensive degradation scoring function to carry out degradation judgment on the current environment; when the degradation result is yes, introducing a structure and motion information independent of an external environment, maintaining trajectory
estimation, and constructing a compensation constraint; introducing a prior semantic constraint and a
large model semantic factor constraint; and constructing a
global optimization objective function, dynamically adjusting the weight of each
modal factor, obtaining an
optimal estimation state, and outputting a high-precision
train positioning result. According to the method, high-precision and robust track
estimation in an extreme scene is realized, so that the continuity, safety and intelligence of
train positioning are guaranteed.