Operating Principle

You can choose between using a compact antenna or separate cabled receivers as your receiving baseline.

The antenna is quick and easy to set up while the separate receivers will enable very flexible designed baselines. Both supports the full 300 meter range.





Separate Receivers




1. Locator

The Locator transmits an acoustic signal which are picked up by the Receivers

2. Baseline

The antenna or separate receivers picks up the acoustic signal from the Locator

3. Topside

The topside positioning computer uses advanced algorithms to triangulate and calculate the position of the Locator based on the received signals from the antenna/receivers


R100 or R300

Underwater GPS G2 comes in two different range versions; R100 and R300 whereas the number indicates the range in meters between the Locator and Antenna/Receivers.

Cylindric Area

The operational area is designed as a cylinder with a radius of 100/300 meter and a depth of 100/300 meter.

Hard Limit

The 100/300 meter range is a “hard limit”, meaning that once the Locator moves outside that range, the position will not be calculated.

Acoustic + Software

The range is limited by the acoustic signal from the Locator and the software running on the Master-D1 positioning computer.

Limiting the search area

If you know you won’t need the full cylindric search area, it is beneficial to the performance of the system to apply some limits.

Limiting Range

You can reduce the radius of where the system will search for the locator.

This is a great idea if you are operating in a confined space like water tanks, pools, fish cages or similar.

Reducing the range even in the open ocean may give you a better performance on short distances.

Limiting Area

You can limit which part of the cylinder you want to operate within.

This should be done if there are obstacles like land or other no-go places for your ROV.

Reducing the area even in the open ocean may give you a better performance.

Limiting Depth?

It is not possible or needed to limit the depth. All Underwater GPS systems relies on a separate pressure sensor to provide the depth of the locator.

Old Explorer Kit vs. new Underwater GPS G2


The most obvious difference is that you can now get 300 meter range. This makes it pointless to look elsewhere for other positioning systems.


The new G2 system has a completely rewritten positioning algorithm. Several years has gone by since we launched the Explorer Kit and thousands of hours of new research has gone into the new positioning algorithm making it better than ever!

Lots of nice upgrades

Based on customer feedback on the old Explorer Kit, we have added lots of new features to the G2 system. Built-in WiFi, Quick deploy antenna and improved aerial GPS is just some examples.


All Underwater GPS systems comes with a pre-loaded Graphical User Interface (GUI).

The GUI runs on the Master-D1 positioning computer and is accessed through a standard web browser.

  • Drag’n drop functionality
  • Map-view with absolute position
  • Grid-view with relative position
  • Live update
  • Points Of Interest
  • Diagnostic tools
  • OS independent (Windows/Mac/Linux)

(video shows previous generation)


Underwater GPS is extremely easy to deploy and start to use!

1. Mount Locator

2. Drop Baseline

3. Input Baseline in GUI

4. GO!


The four receivers can be delivered with cable lengths of 10, 50 or 100 meter. This opens up for very flexible deployment options, even on the largest boats.

Optimal Receiver Setup

When possible, try to spread the Receivers out so you have at least 2 meter between them. Different depths may increase performance.

Make sure the receivers are well submerged and prefferably below the splash zone where there might be air bubbles from waves etc.

Limiting Receiver Setup

If you are unable to deploy a square baseline, you might end up with some limitiations.

In the example below, all receivers are on one line. With such a setup it is not possible to decide which side (A or B) of the baseline your locator is. You have to limit the search area in the GUI to only one of the sides.


Underwater GPS uses a very robust operating principle with multiple receivers.

Combining the multiple receivers with extremely sophisticated software algorithms running on modern hardware, Underwater GPS excels where traditional positioning systems stop working.

The amazing performance comes to display especially when the environment is challenging:

  • Shallow water
  • Inside tanks or pools
  • Close to ship hulls
  • Inside fully populated fish farming cages
  • Inside subsea templates
New areas of application

This new level of robustness opens up for subsea acoustic positioning in areas and applications previously regarded impossible.

Read more about applications


In normal circumstances, you will typically experience an accuracy of ~99%. Translated into distance, this means the Locator will be positioned inside a ball of 1 meter diameter on 100 meter range.

Performance Testing

The video below shows how we performance test the system. By using RTK enabled GPS on a boat, we can generate a tracklog of the boat with ~1cm accuracy. Comparing that track log with the Underwater GPS tracklog we see an extremely high accuracy. The test below is done in shallow water (~6-8m depth) and large concrete walls surrounding the dock.

Available Underwater GPS Products

Underwater GPS G2

Underwater GPS is the most robust acoustic positioning system on the market today! Use this link to build and order your kit.

Underwater GPS Modules

Spare parts