AquaBeacon Selected for Mitou Junior 2026
AquaBeacon — a system that combines light and sound for positioning and mapping in seagrass beds and other underwater environments beyond the reach of GPS — was selected.
At Mitou Junior 2026, AquaWiz's Kamiyama was selected for the project "AquaBeacon — a system that combines light and sound for positioning and mapping, even in seagrass beds." The project's Project Manager (PM) is Masato Bito.
Mitou Junior is a program run by the Mitou Foundation to support creators aged 17 and under who have original ideas and technologies. For 2026, 19 projects were selected from 231 applications. Selected creators develop their projects with mentoring from PMs at the forefront of their fields and funding for development.
AquaBeacon is an R&D project for determining where underwater observations and footage were captured, and for turning that information into maps. It grew out of Kamiyama's work on underwater float development at AquaWiz, which brought home both how important positional information is underwater and how hard it is to obtain. By tying observational data such as water temperature and video to accurate positions, the project aims to capture underwater environments in a more spatial and concrete way.
The primary application in mind is surveying the distribution of seagrass and seaweed beds. To understand how far these beds extend and how they change from year to year, underwater footage must be matched accurately to the places where it was shot. But radio signals barely penetrate water, so GPS cannot be used directly underwater. Estimating position from camera footage is also difficult: seaweed swaying in the current, moving fish, and constantly shifting light patterns make it hard to keep tracking stable landmarks.
AquaBeacon therefore pairs a surface unit with an underwater unit, using sound to measure distance and light to sense direction. The distance between the two is calculated from the time an acoustic signal emitted by the surface unit takes to reach the underwater unit, and the direction is obtained by capturing the underwater unit's light with the surface unit's camera. Combining these with attitude and depth data, the system estimates the underwater unit's position relative to the surface unit, then ties it to GPS coordinates obtained at the surface to place underwater observations on a map. In parallel, the project is working on mapping: using the estimated capture positions as a guide, footage from the underwater unit is stitched together to record seagrass beds and the surrounding terrain in three dimensions. This makes visible an extent that is hard to grasp from individual clips, and builds an information base for ongoing surveys and conservation.
Development spans the full stack, from circuit and enclosure design for both units to acoustic ranging, light tracking, and software for recording and analyzing sensor data. The first configuration analyzes recorded footage and sensor data in post-processing, with positioning and mapping accuracy evaluated in test environments such as swimming pools. Through repeated simulation and real-hardware testing, the project will examine how water turbidity and vehicle motion affect the estimates, and establish the conditions under which the system can operate in real underwater environments.
AquaBeacon also publishes not only its source code but also its circuit, PCB, and enclosure design files, a simulator for validation, and development documentation on GitHub. By openly sharing how the system works and how it is evaluated, in a form other developers can reuse and build on, the project aims to become a technology widely used by individuals and teams working on underwater observation and seagrass surveys.
For an overview of the project, see the AquaBeacon website; design files and source code are available in the public repository directory.