Waterlinked GPS position readings drifts

Third Party Products Sonar and Acoustics
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Hi all,

We are using the Underwater GPS G2 and the locator U1 for the Bluerov positioning in a lake.

Before doing our experiment in the lake, we did some tests of the position accurancy of the locator in a water tank with the size of 2m *2m *1m.

However, the position data displays on the GUI website showed a drifting.

The error keeps floating even when the locator is firmly fixed, such as the x position will drift from 0.33 to -1.11.

I attached a few photos of the experiment environment.

I am not sure if the size of the tank is too small that leads to inaccurate positioning, or if there are some items at the bottom of the tank which influence the transmission of the acoustic signals.

Do you have any advices to improve the situation? Is this drifting acceptable? (Because the final goal of our project is to design a control system for the ROV, so the accurancy position data is quite important to us).

Will the situation be improved if we do the experiment in a lake?

Thanks,

Neve

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Hi @Neve,

The Water Linked GPS page specifies that it supports range limiting for use in small areas like water tanks and pools - is that something you’re already doing?

Beyond that it may be helpful to

  • update to ArduSub 4.1 (we’ve just released it as the new stable), and
  • re-calibrate the vehicle sensors

Perhaps @wlkh will have some additional recommendations :slight_smile: