Interesting service bulletin ...
 

Not directly linked with the X5, but a interesting service bulletin (dated August 2006) from BMW for the E46 Coupe and a poor GPS reception. Apparently the TCU may interfere with the GPS signal. In the bulletin they suggest moving the GPS antenna to another location!

http://www.alldata.com/tsb/BMW/11544...6/8419061.html

Gps
 

Thanks apw2607 for the info.

GPS receivers are very sensitive and are vulnerable to cellular and PCS band interference.

Its interesting that you report this TIS suggests moving the GPS antenna, in the E53 the antenna is in the rear, plastic 'spoiler' and seemingly a good location. We dont have any easy option to move it. I think this current location, high up, within a plastic casing is ok. But the (small) disadvantage is that is it somewhat close to a large, co-planar conductor (the roof !). The cell phone antenna is also in this plastic 'foiler'.

The GPS system needs a greater sensitivty than the phone (cellular/pcs) system. So I would suggest that for E53, moving the cell antenna away from the GPS antenna would be preferable to moving the GPS antenna.

Scotty.