offboard height problem

[張為超]

Hello team:

I found out that in offboard mode, the altitude of the drone looked fine at first. But after a few flights, the altitude started to drop. Even I switched into position mode, I have to set my throttle a little bit higher to let the drone to stay altitude.

So, my question is:

1. What could have caused this to happen? Do M500 and seeker use QVIO to estimate their height?
2. Is there any way to avoid this situation? Or i just need a better feature to stable QVIO?

Any suggestion is welcome, Big thanks!

[Adrian Hidalgo]

@張為超 When the drone is flying, does the Local_Position_Ned in QGC, X, Y, Z do they correspond to the decrease in elevation?
Same goes for QVIO.
Does the problem persist after a powercycle. This normally fixes the issue or by recalibrating the sensors. Sometimes VIO starts to wonder a bit causing altitude to vary. Make sure there is enough points of interest for the camera to track

[Dobry Kolacz]

@張為超
run "voxl-inspect-qvio -n" to see a readout of qvio positioning and number/quality of features the camera is seeing

I would recommend re-calibrating the compass within QGC to possibly fix the issue with altitude mode issues

I would also recommend cleaning the camera lenses with a clean cotton swab or microfiber cloth as the camera might have gotten dirty, resulting in interference with qvio's ability to work

QVIO is used for height/positioning when you are running your drone on the indoor vio parameters. This can be set up on both M500 and Seeker drones

[張為超]

@Adrian-Hidalgo @Dobry-Kolacz Thanks for your reply, so the drone uses QVIO to control the altitude (I think it uses barometer or something else) which perfectly explains why the altitude sometimes drifts as our floors are a bit lacking in texture. I'll try adding some texture to the floor and give it a try. Thanks.