Verification testing by Askö Island

After being granted advance permission by the Swedish Armed Forces and the County Administrative Board, a validation test for RWMT’s technology was conducted in June 2019 at Stockholms University’s research facility outside Askö in the Trosa Archipelago.

The test’s purpose was to validate the system’s ability to detect and produce images of buried objects for identification.

Before the test, an external, independent diving company had been assigned to bury three objects in the seafloor sediment. After hiding the objects, the divers marked their exact coordinates and location.

The objects were selected to be as difficult as possible to find, with acoustic properties similar to those of the surrounding seabed. They comprised a sand-filled wooden box, two wooden joists, and a concrete pipe. In addition, seafloor conditions around Askö are exceptionally difficult, as the sediment reflects echoes, causing signals to interfere with and interrupt each other. Besides difficult conditions, minimal time was provided for the preparation and calibration of the measuring equipment before the test.

Despite the challenging conditions, all three objects were found and could be identified during the validation test. The test showed that even when the seafloor consists of different layers of sludge and moraine, RWMT's sub-bottom scanning system gives good results.