Thanks for the interest in our products!
The accuracy will be given by the distance from the Locator to the receivers. In a small tank like shown in the video acoustic environment has lots of reflections which affects the accuracy. I think you can expect an accuracy to be something like 5-10cm when properly configured. The best configuration in a small tank is spreading the receivers in an L shape in the corner of the tank and setting the search range slightly bigger than the tanks size.
If you want to see how the Underwater GPS GUI works, please take a look at our demo site:
More information about the Underwater GPS in our documentation site: