Abstract: Intertidal topographic surveys have a fundamental role in the protection and utilization of tidal flats. A combined shipborne single beam bathymetry echo measurement and airborne laser LiDAR integrated system is proposed. Firstly, the ODOM MKⅢ dual-frequency single beam bathymetry is used to collect and verify the accuracy of the point cloud results in the intertidal zone of the UAV airborne LiDAR. Then the key indicators for the implementation of UAV airborne LiDAR low-tide aerial photography are designed in complex environments. Finally the intertidal zone with high precision is optimized by combining the land topography of airborne LiDAR tidal flats at low tide and the underwater terrain of tidal flats with shipborne single beam bathymetry at high tide. Scale topographic map surveying method. The practice shows that: ① 816 measuring points in the overlapping area are selected to compare the two measurement accuracies, and 99% of the compared points have the difference in elevation within 0.2 m, indicating that the airborne laser LiDAR measurement can meet the measurement requirements of coastal tidal flats.② The UAV entering and leaving the survey area should be rotated in turn, and the horizontal flight combined with the figure-of-eight flight should be used to avoid the accumulation of IMU errors.③ The measurement system is of reference significance for the promotion of high-precision large-area topographic surveying projects in the intertidal zone.

Key words: single beam bathymetry, UAV, airborne laser scanning, intertidal zone, route planning