Dropix & M8P RTK XL - no stable course

I did a setup with a dropix and the drotek RTK XL module.
Calibration went well, ( Compass switched only to external )

but the black course line is changing its direction allways…[dropix ground course neo8p rtk]


thx for any advice.

If the copter is at ground the Gps cannot in any way know what is the heading so the black line changes.

Thx, so in this case, why the GPS Line still changes its direction, when the copter is in the air ?
I don’t have a problem , copter works well, but i noticed that doesn’t matter if the UAV is on the ground or in the air…

If the copter is hovering in the same position no heading informations from the gps , if the copter is moving the black line shoud show the correct heading.