We discussed a bit earlier this week. I think options are:
Mount on top away from GPS antennas (Basti brought this up, pro: transform is simpler, con: have to clearly identify antenna locations and may be hard to avoid interference)
Mount on front (see picture). I like this option. Cables will be easy. Transform will be more confusing. Note: still has more than enough clearance from the cameras.
Mount to bottom face of frame (see other picture).
This came up in discussion this morning:
I had expected the GPS to be mounted to the top of the robot with dual lock. However Basti suggested that could interfere with the onboard GPS.
We need to consider alternative locations