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ROV horizon not level

When starting up the ROV ( on a level surface) The horizon jumps CCW indicating that the ROV is not sitting level. When pressing stab mode in the water the ROV levels the horizon by rolling the ROV to sbd side a few degrees. I have re- calibrated the everything several times but no change. Can this be a software bug? Is really annoying as it stirs up the viz close to the seabed as the vertical thrusters spins all the time.
Anybody else had this issue ?

This link http://ardusub.com/troubleshooting/#troubleshooting
Will give you the solution

Page not found message when clicking on the link

@SDI, indeed, the website moved last month. This is the updated link: https://www.ardusub.com/troubleshooting/troubleshooting.html. However, I don’t think your problem is addressed there.

First check that the Pixhawk is mounted flat in the electronics enclosure, and that it has not come loose. Then perform the accelerometer calibration, and at each step, set the vehicle on the ground lying on its left side, right side, and back, and nose. This cant really be done during ‘nose up step’, but do your best to get it straight up and down there. The key during each step is to have the vehicle sitting completely still before hitting the ‘Next’ button.

After you are finished with the calibration, set the vehicle right side up and look at the horizon indicator to see if it is level. Reboot the ROV and note any change in the horizon indicator when it connects again. If it still is not looking good, you can go to the sensors menu where you do the calibration and click the ‘level horizon’ button, which should bring the horizon level.

Please let me know your observations.


Thank you for the tip. I will try as soon as I get back from offshore.

It turns out that Oystein’s Pixhawk was mounted loosely and was sitting in a rotated position inside of the enclosure. Re-mounting the Pixhawk vertically resolved the issue.

Just for the sake of good order. The Pixhawk was not mounted loosely per say, it was mounted on the soft foam pieces but some force from the wires on one side made the foam compress a little at the same time the whole insert was skewed as well…just a little. But combined this was enough to get the horizon wrong and outside the capability of the level horizon function to fix. It was not that easy to see and since the level horizon did not fix it I was led to believe that it was a software issue. Thanks to Jacub I investigated further by opening the bottle and only then I saw that the pixhawk were not vertical.