Hello,
Attached is a log from Cockpit.
I am continuously losing connection to the vehicle during actual dives. I don’t see this happen during bench testing.
Running :
Seaview Systems Fiber Optic Cable
Navigator
Blueos 1.4.3
Ardupilot 4.5.6
Cockpit 1.18.2
Network Test (Tether diag shows “0”)
Could someone pick out the causing error to do so?
Any help would be appreciated.
Thank you,
Hi @minskim88 -
No attached log is evident?
Sorry, Just attached and more details.
Adding couple more logs from cockpit (7/23 - Dive that just took place & 7/22 - Arm/disarming on a bench).
7/23 dive ran about 20mins before it started losing connections.
Cockpit (Jul 23, 2026 - 13꞉01꞉10 GMT-7).syslog (130.1 KB)
7/22 bench test log
Cockpit (Jul 22, 2026 - 13꞉11꞉47 GMT-7).syslog (44.8 KB)
edit
Adding another log (vehicle was armed on the bench again once we returned) - No heartbeat lost.
@minskim88 could you get us the BlueOS logs as well for both sessions (bench and water)?
From Cockpit’s logs it looks like a major connection issue. That could be something in the network part (e.g.: bad connection in the tether), but more likely to be something in the vehicle (e.g.: CPU struggling, voltage dropping on the Pi, etc).
Hi Rafael,
The ROV went for a Dive again today.
Last night, I reset the network IP and managed to find that there was another adapter at 192.168.2.1
The ROV worked without being disconnected up until, I turned on the Cerulean DVL extension (operating DVL-75), so that I could utilize the DVL for Surftrek mode with depth measurement from the DVL.
During this time the vehicle became sluggish and tend to lag in command or not acknowledging. I’d have to press the button’s couple times to control.
I am attaching logs from today. I know for sure at 13:10 pm till 13:15pm Pacific time, I turned on the DVL extension.
Cockpit (Jul 24, 2026 - 12꞉06꞉24 GMT-7).syslog (227.5 KB)
Cockpit (Jul 24, 2026 - 13꞉05꞉34 GMT-7).syslog (108.0 KB)
00411-2026-07-24_20-39-56.tlog (8.0 MB)
00409-2026-07-24_19-18-08.tlog (8.7 MB)
00000114.BIN (6.6 MB)
One of the .BIN is too large, What would be the best way to share?
Here is the logs(tlog and bin from yesterday)
00389-2026-07-22_21-18-09.tlog (6.5 MB)
00387-2026-07-22_21-18-09.tlog (4.1 MB)
00385-2026-07-22_20-58-04.tlog (12.3 MB)
00397-2026-07-24_16-53-09.tlog (1.2 MB)
00395-2026-07-23_22-01-33.tlog (862.9 KB)
00393-2026-07-23_21-06-27.tlog (12.5 MB)
00000109.BIN (5.4 MB)
00000108.BIN (11.5 MB)
00000107.BIN (2.8 MB)
One thing worth asking: if you close Cockpit and open it again, does the problem “reset” (be fine for a couple minutes and then happen again)? Or it will be there as soon as Cockpit is restarted (couple seconds)?
The occurrence is totally random, especially in the field. I usually launch from the boat.
It has happened right at start in the field. I would wait and confirm reconnect. Sometime occurs few minutes into the dive. But also it can be very unstable and occurs repeatedly three to four times one right after the other.
On bench it is mostly stable, but has happened once.
This is just my hypothesis and it does occur more at area with more magnetic anomalies where compass values are unstable, leading to bad EKF. Hence occuring more in the field with metallic materials near by. Once underwater it tends to stabilize and work until coming near the launch vessel, steel pile and etc.
Bench test with ROV not moving, stable compass reading leading to no heartbeat lost or very low chance of occurring.
Understood, and this adds a lot to the investigation.
My last questions still applies thought: restarting Cockpit does fix anything? My goal with this question is to help us isolate the problem to being in the topside, in the vehicle side, or in the comms.
Hi Rafael,
I would not say that restarting Cockpit solves the issue.
I know I already mentioned this as well,
Turning off the Cerulean DVL extension, makes the control smoother and connection is stable. in which I dont get Vision_Position_Delta for mavlink.
That is probably where we need to look at right now, so let’s record a MAVLink dump from Cockpit.
First of all, enable the extension. Then open Cockpit, Menu, Tools, MAVLink, and on this screen please click the start button. Wait for at least 1 minute, click to stop the recording, download the dump and send it to us.
Sounds good. I will be heading out tomorrow for a dive.
Will get you some files by end of tomorrow.
Hi @minskim88 -
It seems the feature is only available in the beta, not stable channel. Easy enough to update!
Thanks Tony,
Is that the latest beta? I will give that a go.
Also I‘ve been reading about mavlinkserver.
Currently the ROV is set with mavlinkrouter.
What would you recommend? Switching to server option?
I’ll try get the dumps tomorrow.
thanks,
Hi @minskim88 -
Yes, that is the latest beta release I linked.
Trying mavlinkserver, and the latest BlueOS 1.4.4 beta (which is very close to release) would be a great troubleshooting step as well!
Hi,
since the first release of cockpit I wasnt able to do only one dive without heartbeat lost. Dry tests on the workbench are OK with less heartbeat issues exept some forced resets alerts. I use the desktop app because the browser version is too laggy.
I still use QGC for operation in water. Since I updated every component to the actual stable version, cockpit doesn’t show a videostream anymore. In QGC the vehicle is operationable but alerts due to missing parameters come up when I go into the settings. My ROV is build in 2017 and now I’m going to replace the pixhawk and the rasp 3B with rasp4, hoping don’t getting temperature issues.
This post is only for your information, because the heartbeat lost during the dive with cockpit is well known from my side.
Hi @schleitaucher -
That’s quite a well aged ROV! 
A pi3 is definitely worth upgrading from! Otherwise QGC / legacy Companion OS may be a better fit for the Pi3/Pixhawk… I wouldn’t expect temperature issues if you use a heatsink - the Navigator comes with one, and would also be a significant upgrade from the Pixhawk!
You may want to try Mavlink Server vs. the default older Mavlink Router - it can help with heartbeat lost issues. It’s interesting you don’t have a video stream in Cockpit anymore - can you share what version of it you’re using? As well as your BlueOS and ArduSub versions? If a stream shows up on the Video streams page in BlueOS, and in QGC, then it should be available to select for your video player idget in Cockpit under Edit Layout (top pencil-shaped icon in main menu)
That notification in QGC is harmless, but in general I abandoned it due to frequent crashing issues on M series Macs…
Thank you for your input @schleitaucher
I may just go back to QGC, but really like the layout of the Cockpit.
My build is Pi4 w/ Navigator so it may be little different.
Really havent had a time to go out again. Will let you know if QGC works better.
Thank you,
