Method and apparatus for calibrating structural errors in a conical scanning airborne bathymetric lidar system

A method for calibrating structural errors in a conical scanning airborne bathymetric light detection and ranging (LiDAR) system, comprising:

• deploying a plurality of global control points, a plurality of local control points, and a plurality of laser retroreflective targets on a target plane of a calibration field, and arranging two survey stations within the calibration field;
• establishing a global control coordinate system, and acquiring coordinates of the plurality of global control points in the global control coordinate system using a total station;
• determining, based on the coordinates of the plurality of global control points in the global control coordinate system, coordinates of the two survey stations in the global control coordinate system via a forward resection method and a trigonometric leveling method;
• acquiring, based on the coordinates of the two survey stations in the global control coordinate system, coordinates of the plurality of local control points and a center of an airborne bathymetric LiDAR reflector in the global control coordinate system using a forward intersection method and a trigonometric leveling method;
• acquiring slope distances from the center of the airborne bathymetric LiDAR reflector to laser footprints on the plurality of retroreflective targets and drive motor rotation angles using the conical scanning airborne bathymetric LiDAR system;
• acquiring, based on the coordinates of the plurality of local control points in the global control coordinate system, coordinates of the laser footprints in the global control coordinate system using the total station;
• constructing an error equation according to the slope distances, the drive motor rotation angles, and the coordinates of the laser footprints in the global control coordinate system, based on displacement and rotational geometric relationships between a laser scanning reference coordinate system and the global control coordinate system;
• and
• iteratively solving the error equation using a least-squares adjustment of indirect observation principle to derive structural error values of the conical scanning airborne bathymetric LiDAR system.