The invention relates to an unmanned ship global path planning navigation method based on nautical chart data, which comprises the following steps: firstly, receiving longitudes and latitudes of a starting point and a target point, calculating and expanding a search area, acquiring and
processing hindering object information from nautical chart data, then converting coordinates into Mercator XY coordinates and inputting the Mercator XY coordinates into an improved A star
algorithm, according to the
algorithm, a path is planned through gridding
processing and grid boundary expansion considering a safety distance, in path planning, node expansion and
collision detection are carried out by adopting a new cost function in combination with a dynamically adjusted cost
expansion factor, path safety is ensured, the planned path is simplified, and finally grid path points are converted back to
latitude and
longitude coordinates, so that the path planning precision is improved. Forming a global
navigation path of the unmanned ship; the sea chart data and the intelligent
algorithm are effectively combined, an efficient and safe navigation scheme is provided for the unmanned ship, target category information in the sea chart is fully utilized, navigation obstruction data are extracted, a sea safety grid map is constructed, and the accuracy and efficiency of path planning are improved.