Hi @Qlowe,
Given you’re showing the DVL’s own position estimate here, it’s likely the DVL is giving faulty readings to ArduSub, which is then failing to maintain the position because the information it’s receiving doesn’t make sense.
The main reasons I can think of for a DVL giving faulty readings are:
- usage in an unsuitable environment, where it can’t get a good lock
- if you’ve used the same DVL (or another of the same type) in that location before then that’s unlikely to be the issue
- insufficient/noisy power supply
- this thread may be relevant
- faulty/damaged DVL
- you’ll likely need to contact Water Linked support if this is the case
As an extra possibility, if you’re also seeing errors about no depth sensor connected then this thread should help, but I wouldn’t expect that to be relevant given you’re seeing the issues in the DVL’s own estimates, which shouldn’t be related to ArduSub’s depth sensing.
Just to clarify, do you have two Fathom-X boards in the vehicle, going over the same tether pair, to a single Fathom-X at the surface? That should work, but if instead you have two sets of Fathom-X boards using independent tether pairs there will likely be issues with cross-talk between the pairs that messes up the communication of one or both lines.
We would generally recommend using an Ethernet Switch in the vehicle, rather than an additional Fathom-X board.