Break Water Survey:
Breakwater and survey cabin
Armoured breakwaters are intended to protect seashore installation (arbour, oil terminal…) against waves, they are generally covered by concrete blocs with different sizes and shapes.
Some bloc type allows ‘single layer” configuration which reduce the total concrete volume necessary to build the breakwater, but required a precise placement during construction.
Diver pointing an ACCROPODE
Acoustic to cartographic coordinate system transformation:
The transformation from local acoustic to absolute cartographic coordinate system is defined by measuring the acoustic coordinates of two reference points named pivot and lever, the absolute coordinates of these two reference points being measured at 2/3 metres depth using a total station from the pier.
Then, the calibration just consists of directing the diver to the reference points and to pick the position in the Autocad drawing and wait for acoustic measurement completion.
The calibration lasts about 15 minutes and is valid until the next Base translation.
The diver holds the Pointer and is able to speak to the survey cabin, his work consists of swimming from bloc to bloc and pointing the bloc centre with the Pointer and waiting for measurement completion, which is managed from the survey cabin.