The invention provides a PPPRTK /
LiDAR / INS fusion positioning method based on hierarchical optimization. The PPPRTK /
LiDAR / INS fusion positioning method comprises the following steps: firstly, constructing a front-end tight
coupling module of
LiDAR and INS, extracting
point cloud geometric constraints, and combining the
point cloud geometric constraints with IMU pre-integration to form LIO
odometer factors; then obtaining multi-
system multi-frequency GNSS original observation, unifying time, coordinates and antenna reference, and carrying out multi-stage correction on the observation; a PPP-RTK / INS tight
coupling observation model is established under an SRIF framework,
linearization and residual construction are carried out on a non-difference and non-combination equation, a joint state is constructed, and a
floating point-fixed two-stage
ambiguity resolving and
quality control method is adopted; and finally, performing joint optimization on the front-end LIO factor and the PPP-RTK / INS factor by utilizing a
factor graph, eliminating abnormal observation in combination with a robust kernel and a residual error threshold, and outputting a continuous and accurate vehicle
pose. The method can effectively improve the continuity, convergence speed and precision of positioning in complex scenes such as urban canyons and elevated interchange, and is suitable for the fields of navigation, automatic driving,
free flow charging and the like.