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.
It is 99% of the distance between the locator and the receiver. @wlkh may provide more insight.