Abstract: To address the challenge that single-technology approaches can not simultaneously cover high-altitude blind zones and near-ground intricate components in digital preservation of ancient pagodas,this study develops an aerial-ground collaborative technical framework for fine-grained real-scene 3D modeling,enhancing the accuracy and completeness of historical building digitization.Innovatively integrating coarse-model-guided intelligent route optimization with multi-source aerial-ground data synergy: UAV photogrammetry constructs a coarse model via orthophotography to guide encircling close-range photogrammetry,enabling high-precision data acquisition of pagoda tops and facades; ground/handheld LiDAR supplements millimeter-level point clouds of base structures; ICP point cloud registration,bilateral filtering denoising,and RANSAC fusion algorithms achieve seamless integration of aerial-ground data.Applied to Luoxing pagoda,the collaborative model demonstrates significant improvements: aerial triangulation achieves a georeferencing RMSE of 0.038m,point cloud registration precision reaches 5mm,and texture ghosting is improved obviously.Structural deformations and voids at the base are fully resolved.This method overcomes technical barriers in coordinated high-altitude/near-ground data acquisition,providing an efficient,non-contact,high-precision solution for digital conservation of cultural relics,thereby robustly supporting China's national cultural digitalization strategy.

Key words: aerial-ground collaboration, real-scene 3D modeling, point cloud fusion, ancient pagoda conservation