Visual positioning system and method based on high-precision three-dimensional map

The invention discloses a visual positioning system and method based on a high-precision three-dimensional map. The system comprises a data acquisition module which is used for acquiring the image data and GNSS data of a current position, an acquisition aiding module which is used for data transmission, a power supply module which is used for supplying power to a system module, and a data processing module which is used for storing visual map information, processing the acquired GNSS data and image data and eventually realizing a positioning function, wherein the processing comprises GNSS data matching and feature point extraction and matching. The method is based on the high-precision three-dimensional map and comprises the following steps: carrying out preliminary positioning via matching of GNSS information; then carrying out image-level positioning via matching of global features; and finally carrying out measurement-level positioning and calculation via matching of three-dimensional local features so as