MANTAS II
Coral Reef Settings
Demonstration of Topo-Bathy LiDAR in a Coastal Environment
The ASTRALiTe Lidar made measurements from a DJI Matrice 600 Pro UAV during the Applied Research Lab (ARL) MANTAS II Tech Demo at the University of Hawaii’s Institute of Marine Biology (HIMB) on Coconut Island in October of 2018, showing the topo-bathy LiDAR System's capabilities in a coastal environment. The results from this demonstration validates the system's performance in favorable operating conditions, capturing and producing high-quality data sets from our prototype system. A total of seven flights were conducted, the longest being 17 min. The ASTRALiTe LiDAR has its own battery power, enabling the UAV to fly for longer on its own battery.
The above images depict the scene from the MANTAS II Tech Demo, where the Topo-Bathy UAV LiDAR system was put to the test in mapping coral reefs. The images to the right are from the UAV's field of view as it flies over the reef and the coral that is underneath the swath of the LiDAR. A special feature of the demo was measurement of underwater coral reef structures at centimeter-level depth resolution. Over a series of three days the ASTRALiTe LiDAR was successfully flown on the windward side of the island in conditions that included salt spray and significant surf, collecting dune, inlet and lagoon profiles, and near-shore bathymetry.
6'' Diameter Pipe
One of the highlights in the data capture from the demonstration depict the scene from the MANTAS II Tech Demo, where the Topo-Bathy UAV LiDAR system was able to identify a 6-inch diameter pipe among the coral reef bed. The LiDAR allows for accurate measurements, in contrast to the photo to the left, which does not have any dimensions.
One of the more interesting flights from that demonstration involved capturing a pylon that was protruding out of the water in the middle of the bay. The UAV pilot did a pass of the UAV over the pylon and in the swath of the LiDAR system.
An analysis of the data shows that the pylon was successfully captured and was about 30-cm above the water.
3D Map of Coral Bed on Coconut Island, HI
A calibration target (cinderblock) was placed on a boat ramp to demonstrate the LiDAR's true topo-bathy utility. The UAV passed over the boat ramp to map the transition from water-to-land and to capture the block, in which the data captured the calibration target at cm-level resolution. This same resolution can be seen in the data from that flight, where the voids in the side of the calibration block are clearly visible in the point cloud.
