It's "long" time I did not use it, actually, so I'm not up to date with how I managed it in details. I used a Python prog to read location data (from GPS or any GPS emulator) and this prog creates a new KML file every second in its loop. Google Earth reads that KML file to update the icon location.
I add the KML files I used here for you to study (read them with some Notepad. You may find plenty of info about GE on Google. I also add the python script I used. Hope this helps.TOPdownUAV_gps.kml TOPdownUAV_gps_link.kml TOPdownUAV_track.kml TOPdownUAV_track_link.kml gegpsd_reto_4.py
Following are the settings to set up the link files in GE (screenshots from french version, sorry)