This problem can be caused by a few different things, depending on the exact nature of the drifting. Select the more precise description below to see how to fix it.
The pan axis of your Helix moves so slowly that you can’t see it move, but it clearly drifts over several minutes
This can probably be improved slightly by recalibrating the gyros on your Helix, but the only way to truly eliminate it is to get an encoded Helix. Encoded Helixes should not do this. If you want to recenter your Helix, see https://kb.letus.net/my-helix-isnt-centeredis-panned-to-the-left-or-right/
The pan axis of your Helix drifts visibly, but only when the joystick or RC controller is connected to it.
This is a problem with the trimming of the RC controller or joystick. If you are using an RC controller, make sure that you trim the RC radio in accordance with your radio’s manual. If you are using a joystick, you must do this from within the SimpleBGC GUI or the iOS app. The SimpleBGC GUI is simpler and the recommended method for doing this. To trim it, you can:
Connect to your Helix with the SimpleBGC GUI.
Go to the RC tab.
Scroll down until you see the section marked “RC Sub-Trim”
Press the AUTO button.
Hit the Write button.
The Helix drifts in a slow, but visible manner, even without a joystick or RC controller connected
This is usually caused by a gyro that needs to be calibrated. You can calibrate these in either the iOS app (orientation/calibration screen) or the SimpleBGC GUI (IMU calibration helper). The iOS app is the easier way to do this.