Weird behavior after change to Navigator from pixhawk1


My team has recently changed from a pixhawk1 to a Navigator setup, and with the change some issues occured.

Ardusub firmvare: 4.1.0
QgroundControl: 4.2.4
BlueOS: 1.0.1

There are three main issues we are facing, and I am not sure if they are all separate issues or if they are correlated.

1. Ocsillations - They vehicle started oscillating in the roll, and slightly in yaw. We managed to reduce/remove the ocsillation by tuning the PID controller for roll rate and yaw rate.

2. Yaw with an extensive pitch angle - In our work we often need to look underneath objects. This means that pitching the entire vehicle up and manouvering it in heavily pitched position is normal. After the change from pixhawk1 to Navigator the behavior of the vehicle in this position has changed. In pixhawk1 the yaw movement was as if the Z-axis was pointing straight up towards the surface. With the Navigator it seems like the yaw movement follows a Z-axis pointing straight up from the vehicle.

3. Roll static error - After manouvering the vehicle as described in 2. and then reducing the pitch angle to level out the vehicle, it has gained a static error in roll angle which does not diminish. The control mode needs to be toggled stabilize - manual - stabilize for the vehicle to level out.

Do you have any ideas what can cause these issues, and potentially how to resolve them?

If any additional information is needed, please reach out.


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Here are some animations showcasing the change in behavior that we are experiencing:

This was the movement the vehicle made when yawing with a pitch angle with the pixhawk1:

This is the new movement when yawing with a pitch angle using the Navigator:

Is there a parameter change that causes this or may it be a result of something else?