The accuracy of the underwater gps is ~99% of the range according to the specifications. Is this range the distance of the locator from the topside? Or the distance of the locator from the receivers? I am planning on running this in a small tank (like the one shown in one of the demos on the BlueRobotics website here: https://www.bluerobotics.com/new-product-underwater-gps/) and was wondering what accuracy to expect.
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.