PENTA-OCEAN CONSTRUCTION CO., LTD. POV-DA is a drone capable of taking off and landing on water, equipped with high-precision GNSS, thrusters, and a bathymetry sonar (Photo 1). The current position (X, Y, Z) and water depth of the POV-DA that has landed on water can be grasped in real time on the operation screen on land. In addition, by specifying the horizontal position (X, Y) of the observation point on the operation screen, it is possible to navigate the POV-DA to the observation point on the sea using the underwater thrusters, or to keep the POV-DA at a fixed point at the observation point even in the presence of waves and currents. Using these functions, it is now possible to easily and efficiently perform (1) bathymetry and (2) wave observation from land.
Bathymetry function
In the construction management of construction works such as breakwaters and quays, since it is not possible to directly check the underwater construction status with the naked eye, bathymetry using survey vessels1 and red bathymetry2 are generally carried out. The introduction of POV-DA makes it possible to shorten the bathymetry time, and the bathymetry data is displayed wirelessly on the operation screen in real time, making it possible to grasp the progress of underwater work and whether the amount of soil input is excessive or insufficient, and to speed up decisions on whether to continue work. The bathymetry performance is about +/-10 cm different from general bathymetry methods, and it has been confirmed that it has practical accuracy for construction management.
Wave observation function
In offshore construction, the feasibility of construction is judged based on various weather and ocean forecast data or wave observation data in the vicinity of the site for construction management and safety management. In addition, the feasibility of construction is judged visually from the coast before construction.
By introducing POV-DA, the wave height and period calculated from GNSS data are displayed on the operation screen in real time, allowing the local wave conditions to be grasped and the feasibility of construction to be judged more quickly. The difference between the observation results of POV-DA and those of a wave height meter is within 10% on average, and it has been confirmed that it has practical accuracy for construction management.
POV-DA not only contributes to the efficiency of construction management in offshore construction and the speed of judgment on whether construction can be carried out or not, but also enables aerial photography from the sky, making it possible to quickly grasp the situation both on land and underwater in the event of a disaster.
In the future, we plan to expand the marine measurement functions by installing a multi-item water quality meter and water sampler, and to expand the scope of use to the preservation and investigation of the marine environment in offshore construction.
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