Performance Evaluation of Drone Operated Dual Waveform Bathymetric LiDAR

Abstract. Flooding has been the most critical environmental threat to human settlements already for decades and due to climate change both the quantity and the volume of floods are increasing globally, making surveying and studying of water environments an ever-increasing interest. Drone-based surveying technologies are an effective method for detailed surveying of topography, and recently systems for bathymetric measurement have emerged. Fraunhofer Airborne Bathymetric Laser Scanner (ABS) is the first truly lightweight drone operated sensor for simultaneous multiwavelength topographic and bathymetric data acquisition for seamless water environment mapping. To assess the precision, spatial resolution, depth performance and bathymetric accuracy of the novel ABS system, tests were carried out both in dry land and water environment in varying weather conditions. Assessments of the precision and spatial resolution from topographic targets provide standard deviation of approximately 1.5 cm and spatial resolution of 2.5 cm. Despite inconsistencies on targets with low reflectance, the results confirm that the topographic performance is comparable to similar devices and suitable for operation. The bathymetric capabilities of the sensor exceed expectations providing depth penetration of 1.75 Secchi depths in ideal conditions and 1.25 Secchi depths in challenging conditions from all tested flight altitudes. The experimental results demonstrate that the topographic and bathymetric performance of the ABS fulfil the specifications presented by the manufacturer and confirm that the device is suitable to be used for mapping water environments using UAV platform.