GPS antenna needs to be on the rear parcel tray so that it can receive GPS signals through the rear window glass.
The window glass is not allowed to have any metallic tinting on it.

The GPS needs to be switched on and sitting still, and with a clear view of the sky (ie: outside), for 10min to download the current almanac.

Position calc is normnally done within 5min in a Mk3 in a new car in a new part of the world.

Alamnac download needs to happen the first time in a still, non-moving car.

If you still get GPS error then your GPS antenna, GPS antenna cable, or the internal Trimble GPS receiver module (inside the nav) is faulty.

Check carefully the GPS antenna socket on the back of the Mk3 as well, make sure it is not broken, and that the centre pin is still in place.

Just all bmw´s (i´m driving only e38/e65) needs after upgrade the navi max 500km/miles to calibrate there System.
Many people integrate the new system and start driving....
After an upgrade I always start the car without ignition to see the startscreen. Then I switch off all, include the doors closing and going to have tea. After 30min. will the Navi known where you are änd when you will driving with your new lady she´s need any km/miles till exactly calibration...
If your Navi should known via @KiwiJochen Software in which car it is - the navi should calibrate faster

Ok! Thanks I will try that
But on the antenna I have got there is only about 10 inches of line, so I can't place it long away from the navi (Mk3)

Does anyone have a picture of the placement for the antenna ?
Thanks .

Get an extension cable. SMB 50ohm with LM&100 coax cable.

I get them custom made for me, they cost around $40 USD for custom made cable.

You can also buy the original BMW cable from BMW. Refer to www.realoem.com for the part number