Coordinate Systems for tile packages used in Collector for ArcGIS

I have a geodatabase with multiple shapes, domains etc. Everything works fine in ArcGIS online and as well on the Collector for ArcGIS. For better performance while using a tablet for data collection i created tile packages of aerial images to load onto the pads. This as well all worked out. My Geodatabase and all the underlying layers are in the projected coordinate system CH03 LV03 and the tile package is as well.
So what’s the problem?
The created aerial base map has an offset of about 160 meters to NNE in comparison to my GPS located position.
Any idea what the problem could come from?