Connection issues between BlueROV2 and WaterLinked's Underwater GPS G2 using the Integration Kit

Hello everyone,

I’ve encountered an odd connection issue between QGroundControl and the WaterLinked G2 GPS system, and I wanted to pose the situation here. Background: we’ve been running our ROV with a Locator-U1 (the wireless one) for some time, with communication between the topside GPS hub and our ROV laptop facilitated by an Ethernet cable and a network bridge (and we access the GPS GUI via wifi). This all worked fairly well, and we indeed get GPS coordinates that populate our ROV telemetry file. BUT, we experienced numerous instances of communication within the GPS seeming to drop out entirely, such that within the GPS GUI we see a message reading: “No connection to Underwater GPS topside. Please check network connection and power”. As far as we can tell, there was no disruption to the Ethernet cable, network bridge, or the wifi enabling connection to the GUI. Correcting this error required shutting down and restarting the entire system, sometimes including the laptop itself.

In an effort to remedy this situation, we decided to obtain and incorporate the BlueROV2 Integration Kit, enabling hardwired communication between the GPS topside unit and QGroundControl. I was a little unsure about incorporating the Integration Kit as it primarily includes instructions for the Locator-A1 and Locator-D1 – both of which are Locators with cables that are integrated into the BlueROV2 – but we proceeded anyways (using our wireless Locator-U1).

Once we tested the ROV and GPS, we observed multiple instances where the ROV’s camera feed would drop out entirely. The ROV connection could be restored by removing the new BlueROV2 Integration Kit cable that plugs into the newly installed port in the FXTI box. If we plug that cable back in to the FXTI box, the ROV feed holds for a few minutes before dropping out. Also note that we did not see the ROV icon on the QGroundControl map, nor did GPS coordinates populate the ROV telemetry file. So, something is clearly off with how we’ve structured the GPS - ROV communication. (though, note that all other aspects of the GPS system appeared to be working normally, as we saw positioning information on the GPS GUI).

Please note that per the BlueROV2 Integration Kit instructions, the topside GPS hub was set to IP, and the topside computer was set to

I have three (main) questions:
(1) Does anyone know what may have caused the original loss of communication described in the first paragraph?
(2) Is it appropriate to use the BlueROV2 Integration Kit with the Locator-U1?
(3) Based on my descriptions, does anyone have any recommendations for troubleshooting the communication issues between QGroundControl and the GPS system that manifested once we incorporated the Integration Kit?

Note that I also created a WaterLinked help ticket (and am awaiting a response), and I also wanted to see if this community had any insight.

Thank you very much!

Hi @zhrandell
I start with your no 2; Yes Waterlinked with U1 work fine with integration to BlueROV and QGC
I think you have a network issue that hopefully answers no 1 and 3.

As a start, ROV, Waterlinked and Topside QGC computer must be on the same network.
IP addresses must be: Topside, ROV (Companion),
Waterlinked, all as you said.
Companion is supposed to automatically check for a Waterlinked system.
When is finds one, it sends ROV depth (and temperature) to Waterlinked.
At the same time it starts asking Waterlinked constantly for Topside and ROV positions, and feeds that to Pixhawk that forwards positions to QGC.

I think one problem can be that the network to ROV and to Waterlinked is not bridged using tether and Fathom X cards.
You can always skip the tether way to connect Waterlinked, instead use ethernetcables and a ethernet switch or router.
Do not use Wifi to Waterlinked, that can be confusing.
As a start, you should be able to ping from topside QGC computer to both Waterlinked and ROV.
You can also try to ping Waterlinked from companion:
You can check Companion Waterlinked service:
Next thing is to check the status of Waterlinked. Here you should check input depth from ROV,
(and also check that position and heading is correct):

The camera video dropping you could start to track by tether bandwith check.
From main page, go to network scroll down and push buttons “upload” and “download” test:
I guess it also could be a conflict with tether boards, again test using ethernet cables to Waterlinked if its still a problem.

Happy digging!


Thank you very much for all of this, @Boko.

I was able to dig into this with our ROV and GPS yesterday (1/14).

First off, in the setup I described above (following the Integration Kit instructions), I can now verify that there was no communication at, though all the core ROV / QGC communication was as expected (e.g., on, ./system, etc.)

I went ahead and obtained an Ethernet switch, and incorporated it such that both of the Waterlinked GPS topside hub ports were plugged (via Ethernet) into the switch, and then a third Ethernet ran to the GPS laptop. Once I re-enabled the Network Bridge (at, we were back in business (e.g., we had communication at, where I could pull up a command line terminal).

BUT, structuring the communication this way with the Integration Kit required (1) the Ethernet switch, which itself required its own power supply, and (2) an additional Ethernet cable . . . . essentially, I reverted back to the Ethernet communication and Network Bridge mode of communication that I was using in the first paragraph of my original post . . . SO what is the point of having the Integration Kit (especially because we’re using the U1 locator!)?

I then removed the Ethernet switch, structured the Ethernet cable back to the default configuration (bypassing the Integration Kit port), and once more ran the single Ethernet to the laptop with a Network Bridge. What I changed however, and what I’d be really curious to hear folk’s thoughts on, is that I stopped accessing the GPS GUI via wifi at, and instead now access it via Ethernet at . . . Question 1: could me accessing the GPS GUI via wifi have contributed to the occasional loss in GPS communication described in the first paragraph of my original post, which was the original motivation to pursue the Integration Kit?? (note, too, that I may have had the wifi added to the Network Bridge, which I now think probably was an error). I’m hoping the Ethernet GPS GUI communication at is more stable . . .

Question 2: while we are (for the moment) bypassing the Integration Kit (though the Integration Kit board we added is still attached, and I hope that’s okay . . . ), I am confused how the Integration Kit is supposed to work . . . my (albeit, limited) understanding is that, upon incorporating the Kit, the GPS / QGC communication is transmitted via the modified FTXI box to the ROV laptop and QGC . . . but this was clearly not the case for us. So I’m assuming that the Integration Kit is primarily to facilitate communication when using one of the cabled (non-wireless) Locators. Do I have that right? I think I’m missing something (probably multiple somethings!).

Thanks again, @Boko, for your assistance. We’ll splash the ROV tomorrow over the side of the Seattle Aquarium and I’ll report back here what we find . . . fingers crossed we’re fully back in business.


Hello Zach,
We have the Waterlinked system on our BlueRov. It works with the Integration kit. We have never been able to bypass the port. We had the same difficulty with communication with QGC/Ardusub.
The biggest issue for us was the removal of two resisters from the Integration control box to gain functionality. Maybe later versions of the kit don’t have that issue. We use the antenna configuration.
The antenna has corrosion issues when deployed in marine environments.

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Following up briefly to close this thread out . . .

I can now state with some degree of confidence that the Integration Kit indeed does not replace the communication between the topside GPS and laptop that takes place via Ethernet, and to get the Integration Kit working requires an Ethernet Switch, additional Ethernet cables (or alternatively, the Fathom X cards, which @Boko mentioned, but which we did not explore).

Accessing the topside GPS on via Ethernet (opposed to using the topside GPS wifi on appears to have resolved the periodic loss of communication that we were experiencing (see 1st paragraph of first post here) that originally motivation an exploration of the Integration Kit.

Given that Ethernet communication on resolved our communication issues, we have stepped back from using the Integration Kit. This all is probably fairly obvious to most folks here, but as we as simply biologists trying to make use of this tech, it took a minute to get it all squared away. Thanks for your patience.