The excellent performance of Underwater GPS will remain even if you are operating in shallow water areas.

By combining a very robust operating principle using multiple receivers and very sophisticated algorithms running on modern hardware, the system will perform flawlessly even in areas with very little water (<1m depth). The Locator itself will only need to be submerged a few cm for it to be positioned.


Acoustic positioning in water tanks have traditionally been close to impossible as most systems break down due to acoustic reflections.

Underwater GPS changes all this and will provide excellent performance also inside water tanks. This is due to extremely advanced algorithms which are able to remove the false signals (reflections) and keep positioning the original acoustic wave sent from the Locator.

There are however some tanks made of steel which generate so powerful reflections that the false echoes “never” dies. In these rare conditions you may experience degraded or no position.


The size of the smallest ROVs are quickly coming down to a size where traditional positioning systems are simply too large and cumbersome to fit.

The same is true for the price of the small ROVs. Today you can purchase small but full fledged inspection ROVs for only a few thousand dollars. It is obvious that these ROVs will never be equipped with an old positioning system costing many times as much as the ROV itself.

Water Linked Underwater GPS is offered for a fraction of the price of legacy positioning systems making it ideal for the small and cost effective ROVs.


Ship hulls are very often made from steel which in turn generates a lot of acoustic reflections. When inspections are carried out, the ship is usually docked so there might be shallow water and a very close distance to hard harbour walls which will also create acoustic reflections. This environment normally makes it impossible for traditional positioning systems to operate.

Water Linked Underwater GPS will because of sophisticated algorithms and robust operating principle provide you with an excellent position of your underwater vehicle/diver even in this environment.

Be aware that the Locator on the vehicle/diver needs direct line of sight to the receivers to achieve optimal performance. Depending on how large the ship is and where you can mount the receivers, you may need to relocate the receivers to fully cover the ship hull.


The easiest to use Locator is by far the U1. It differs from the other Locator by its integrated acoustic modem which is transmitting the depth readings to the topside. This simplifies the operation as there is no need to integrate the positioning system with the ROV control system topside.

The U1 is also powered by its own internal battery. Because of this, there is no need to use penetrators to feed power from the ROV. It is only a matter of fixing the Locator-U1 to the ROV and turn it on to start positioning.

For easy fixation we supply a default set of steel brackets which will be useful in many situations. We also offer a GoPro mount bracket for those ROVs that offer this as an option. The three M3 holes on each side of the Locator enables you to create a custom bracket

Locator-U1 on Blueye

Mount: GoPro bracket

Locator-A1 on BlueROV2

Mount: Custom bracket

Locator-U1 on Seadrone

Mount: Custom bracket


Fish Farming


A fish cage will need to be cleaned from marine fouling on a regular basis to ensure a good flow of water through the cage. If this is not done, the marine fouling leads to reduced waterflow through the cage and reduced oxygen levels.

Traditional acoustic positioning systems does not work inside a fish cage fully populated with fish. This is due to massive reflections from the fish as well as severe signal dampening by the biomass of the fish.

The Water Linked Underwater GPS system has been thoroughly tested in these conditions with great results. This opens up for combining the positioning system with the net cleaners. Water Linked has developed a tailor made solution for this market where a 3D model of the fish cage is used to visualize the cleaning process as it happens. The net cleaner pilot use this as am amazing assistance system to ensure that no spots are left un-cleaned.

The cleaning process is expensive and as this tool reduces time, it also reduces cost. After the fish cage is cleaned, a pdf report is automatically created as evidence of a perfect job done. This report can be provided to the owner of the cage.


To be able to feed the fish at the right time and place, it is important to know several factors. One obvious information is the location of the fish inside the cage. You do not want to feed at a place where there is only a few fish.

To assist the operator, movable subsea cameras are used to search for the fish and to evaluate their pickup rate when the feeding starts. Until now, a critical parameter has been missing; where is the subsea camera? It does not help to have located the fish if you do not know where you are!

With Underwater GPS mounted on the subsea camera, the position of the camera is displayed in real time as the camera is moving and searching for fish. This critical piece of information enables the operator to optimize location, timing for start/stop and amount of food. The cost savings can be huge!


Any modern fish farming company has a strong interest in documenting their operation. The need to document comes from authorities requiring proof of a safe and sound operation and from the farming company itself looking for data to use in their improvement processes.

Water Linked Underwater GPS and Modem are low cost, high performance tools to lift the documentation of several critical parameters in a farming operation.


In many operations it is not practical to use cabled sensors. The cable itself can bring significant cost. Installation can be cumbersome and time consuming which also adds cost.

Cables are by its nature prone to damage which may cut off the sensor entirely and trigger extensive costs for replacement.

To avoid all this, the Water Linked Modem M64 can be utilized to remove the need for the cable entirely. Connect the M64 with the sensor and a battery pack and you have a fully wireless sensor with a very robust setup. The sensor can be read by another Modem M64 which can reside in a fixed place topside.

You can also mount M64 modems on ROVs, ships or other moving vehicles for dynamic interrogation of the sensors.


It is at any given time critical to ensure that the fish cages are undamaged and are not tangled up in ocean debris or similar. If the integrity of the fish cage is lost, huge numbers of fish may escape resulting in massive losses of value. Escaped fish also represents a significant environmental problem.

ROVs and divers are used to perform regular inspections to ensure the integrity of the fish cage. The missing piece of information after the inspection job is completed is the exact location of potential issues found.

By utilizing the Water Linked Underwater GPS system, all locations can easily be documented to the owner of the cage as well as to the service personnel which will dive to repair the issue.

Underwater GPS will also track the whole inspection job while it is carried out. The track log forms an important piece of evidence that all parts of the fish cage has been inspected.




While you are performing your dive, the topside dive management can follow all your movements and whereabouts in real time.

Having this extra layer of understanding of the dive can remove misunderstandings and increase both the quality and safety of the dive.


If you are doing inspection work, it is valuable to be able to document your dive path. Providing proof of your dive path to the client increases trust and transparency of the business relationship.

The client will know exactly which areas was inspected and won’t be left wondering if the job was carried out as agreed.


Topside dive management without knowing your divers location is not optimal. You will feel disconnected with the subsea operation and there will be room for misunderstandings.

By utilizing Underwater GPS, the topside will achieve a new level of control and comfort knowing exactly where the diver is located.


When the dive involves swimming to specified spots, Underwater GPS will help you do this much easier and faster. While underway to the dive spot, topside dive management can guide you based on your path.

Ocean current, low visibility, night dives and other typical challenges will not cause any problems for Underwater GPS.


Oil & Gas


Subsea templates are challenging for most navigation systems on the market. The structures create acoustic reflections which may cause positioning systems to fail completely.

Underwater GPS is designed to be incredibly robust in these environments and will continue to provide a position of a vehicle operating inside our around the subsea template.


Cabled connections bring significant cost and are in many cases not practical to use. Installation is challenging and time consuming. Cables are by its nature prone to damage which may cut off the sensor entirely and trigger extensive costs for replacement.

By implementing the Water Linked Modem M64, the typical trigger cables can be completely removed.

The Modem M64 is designed to send small amounts of data in a very robust framework. With its two-way operation it is ideal to implement in a wireless control setup. After the control message is sent, a confirmation message can be sent back to the control system which will ensure consistency and control of the operation.


In several applications it is required that both sides of the positioning system is mounted close to the seabed.

An example of this is a resident ROV. The vehicle will stay in a garage/charging structure at the seabed and be sent on assignments from there. The positioning system will be mounted on the garage and the ROV will carry the locator device. In this setting the acoustics will travel close the the seabed and lots of acoustic reflections will occur. Many navigation systems will not be able operate in such conditions. Underwater GPS have no problems and will continue to provide a robust position of the vehicle.


A major component of any autonomous subsea operation is awareness of position. A normal Underwater GPS system is installed so the position is known on the topside and not on the vehicle. But this can be reversed!

The small positioning computer and receivers can easily be installed on an AUV and the transmitter be installed on the AUV garage. This way the AUV will know its own position at all times and can take navigational decisions based on this.

By utilizing the Modem M64, AUVs can send their positions to other AUVs so synchronized autonomous assignments can be carried out.