so ive been dealing with this for like three weeks now and its driving me insane. i have a 3-axis gimbal mounted on my hex, running a Sony a6300 as the payload, and no matter how many times i do the IMU calibration on the gimbal controller the horizon keeps slowly drifting to the left during flight. not immediately, like it'll be fine for the first minute or two and then just starts creeping.

i've balanced the camera as carefully as i can, checked the motor arms, made sure nothing's loose. the gimbal is a Gremsy H3 if that matters. i'm starting to wonder if it's a PID tuning thing or maybe the IMU is just toast on this unit. anyone dealt with this before or am i missing something obvious

had almost the exact same thing happen with a different gimbal brand but similar setup. for me it turned out to be vibration from the motors bleeding into the gimbal IMU and confusing it. i added some extra dampening between the mounting plate and the frame and it mostly went away. also worth checking if your roll motor is running warm after a flight ? if it's working overtime trying to correct something it can't fully compensate for, the PID loop starts to lag and you get that slow drift effect rather than an obvious shake.

the a6300 is also on the heavier end for a lot of 3-axis gimbals depending on what lens you're running. what focal length are you using? if you're front-heavy even slightly the roll axis motor has to work constantly just to hold position and that compounds everything.

might be a dumb question but did you calibrate it outdoors away from metal structures? i made that mistake once and the compass interference was messing with the IMU readings. took me way too long to figure that one out lol