antenna on roof and antenna in car difference

[fugir]

dear laika community,

I am a GNSS researcher and a possible electromagnetic explanation for the difference between measurements taken with an "open" antenna on a metallic car roof and measurements taken inside the vehicle are to do with the style of the antenna and the ground plane

Essentially placing an antenna on a metal roof (within a wavelength of say GPS L1) will introduce re-radiation, pattern distortion and phase center variation

If anybody wants to talk about antenna phase centre calibration (particularly with respect to RTK applications) I am interested

I am a new user of this software and keen to understand more about its design/structure

regards
fugir