We’ve recently experienced some issues with maintaining a DVL fix on our WaterLinked A50. Noticed we’re seeing dropouts in VISO signals c.f. to previously.
Moving to latest WaterLinked A50 firmware (2.6.4).
Rolling back to 2.5.2 of A50 firmware.
We’re running latest releases of Ardupilot, BlueOS and extensions. We’re in touch with WaterLinked and getting their assistance, but if anyone else has experienced this we’d love to learn from it…
Also, any tips on improving visibility for isolating the problem. Would love to know whether this is sensor dropouts or comms dropouts.
Hi @PeterM -
That’s interesting data showing your issue! I would suspect a bad power or network connection? If you ping the IP of the DVL, do you ever have dropped pings, especially as you wiggle the wires around in the enclosure?
Thanks for the prompt response @tony-white . Nothing obvious showing when we Ping the DVL, but I will check the network connection. I’ve added RFND[0] to these plots. Status seems to switch between NoData (1) and Good (4). Would we expect to see NotConnected (0) if there was a network connection issue?
Are you testing somewhere you’ve successfully operated before, or is it possible the environment you’re in is poorly suited to the DVL’s pulses getting reflected back towards the device?
Yes, this in on rocky reef and sandy/shell, in 0-15m. Note that the two examples given aren’t from the same area though. So a couple of possibilities:
DVL sensor is damaged/cooked: We have a second identical ROV so will be field testing that on the same software and firmware. Be good to understand failure modes. Die vs. degrade?
Software: Changes to DVL firmware and/or (less likely) software (Ardupilot/BlueOS/Waterlinked Extension) are introducing different behaviour.
Comms: dropouts.
We’ll bucket test today and try unplugging the unit from the network to see if that’s the case. We can also try swapping the DVLs from one ROV to the other.
Ran a test where I disconnected the DVL network connection. From what I can tell from the BIN logs this still gives NoData (1). Unfortunately it doesn’t give NotConnected (0). If it had we could’ve ruled out network connection issues…
Just another quick update. Still trying to rule out hardware issues, so will do some component swaps. I had some concerns about thermal management on the A50 but got reassurance.
I’m now having a look at the BlueOS Extension for the Waterlinked DVL. There’s a change in June 2025 that relates to how the DVL is found on the network. Wondering if what we’re seeing might relate to that, so will downgrade the Extension to 1.0.8 (May 2025) and will field test (not in a bucket) with that. Most likely a red herring, but worth a shot. FYI @williangalvani .
Latest on this: Looks like DVL hardware failure. We tested both ROVs then swapped DVL. Problem remained with the DVL. The A50 was purchased mid 2023 through BR and via the NZ BR distributor. We’ve been in touch with Waterlinked and supplied diagnostics of Good and Bad units in same terrain. I’d be keen to understand the root cause of the failure. Will post an update if we do.
FYI @EliotBR and @williangalvani
