Sat Nav losing its bearings!

[Keano's Dog]

Hi,
I've recently acquired a a 2004 X5 and I'm having a few problems with the Sat Nav. The problem is that it doesn't seem to know where it is and if you manually enter your current position it seems to lose it.

Last week it placed us in the English Channel and today I was in Hampshire apparently. Even after entering your current Position into the system, by the next day its decided you're omewhere else.

The s/w is 4-1/00. Is this the latest version for a MkIV?

Anyone seen this before?

Thanks.

[KiwiJochen]

Check the GPS antenna is working, go into the Service Menu of the nav to observe all settings

[Keano's Dog]

Originally Posted by KiwiJochen

Check the GPS antenna is working, go into the Service Menu of the nav to observe all settings

It seems to be. Already been into the service menu and it says that its finding 7 Satellites so I guess that means its working doesn't it?

[KiwiJochen]

Does it show signal levels (S/N) of between 6 and 20?

the higher the number the better
Typical is to have 4 to 5 satellites with >7, and from that group, often 2 or so at around 15

If your signal levels are about 0...3 then the antenna is bad

It is rare to have all 8 channels see a satellite.

Also, Almanac should be OK
Gyro should be 2500 +/-100 when sitting still, and increase when turning one direction, and decrease in the other
Wheel sensor should show wheel pulses: positive for forwards, negative for backwards, and change according to speed
Direction of travel must be forwards in all gears except when in Reverse.

If any of these inputs is not working, it'll affect the accuracy of the nav

[Keano's Dog]

Thanks KiwiJochen.

I've had another more detailed look at the Service Menu and it looks like I've no signal.
It tells me that 8 Satellites were found, but the S/N on all of them is 00.0. PRN (whatever that is) varies between 2 and 31, but S/N is zero across the board.The Almanac and Gyro settings were as you said they should be.

Can anyone give me any pointers on how to change the antenna or any idea what it's likely to cost?

Finally, the OS is 4-1/00. Is this the latest version? I've seen reference on the forum to 4-1/100, but not 00.

Thanks for the help. Much appreciated.

[big bob]

PRN = Pseudorandom Noise code. This is the spreading code or cypher key for the satellite you are listening to. It allows the rake receiver to extract the GPS signal from a wideband noise signal. More.

The antenna simply unplugs and gets replaced. It may be in the shark fin making things more expensive. The connector could be FAKRA or MCX or MMCX. Take some pictures of the back of the unit. If it is in the shark fin, consider relocating the antenna to the position used in the retrofit. In the E46 this is in the parcel shelf, but you won't have a parcel shelf.

[KiwiJochen]

The OS version is the latest - the leading 1 on the 100 doesn't display

the antenna is faulty, or unplugged.
You can replace it with an original BMW antenna, or with a generic $20 ebay GPS antenna

[740iS]

Originally Posted by big bob

The antenna simply unplugs and gets replaced. It may be in the shark fin making things more expensive. The connector could be FAKRA or MCX or MMCX. Take some pictures of the back of the unit. If it is in the shark fin, consider relocating the antenna to the position used in the retrofit. In the E46 this is in the parcel shelf, but you won't have a parcel shelf.

Shark Fin antenna is for phone not GPS. GPS antenna is imbedded in the rear headliner, but much easier to check the connection first on the back of the nav computer. You can find the GPS antenna part number here: RealOEM.com * BMW E53 X5 3.0i Gps antenna