Hey! I got a solution that works.
You need to modify the airframe:
~/PX4-Autopilot/ROMFS/px4fmu_common/init.d-posic/airframes
and add the following:
param set-default SIM_GZ_HOME_LAT 47.397742
param set-default SIM_GZ_HOME_LON 8.545594
param set-default SIM_GZ_HOME_ALT 10
However, I cannot take credit for it, Benja said the solution in this post:
And it sounds like another way to solve this is to modify the world file as described in the above post