The Audi Navigation system vs. Blaupunkt's
 

I have some questions (some of which I know the answers to, but are for discussion purposes) regarding our Nav system vs. Blaupunkt's system. They both feed off of the same disks so I would expect similar features and functionality, but they don't.

For starters, do we have wheel sensors in our cars? I get reception in place I shouldn't (I've used GPS for several years) and can't figure it out.
Do we have to calibrate our systems, and if so, is it self calibrating, or is there some link to the odometer, or are they calibrated another way? I haven't had to calibrate mine, but maybe that was done at the factory and I've yet to kill the battery so I'm not sure.
Why can't we use the Travel guide? This seems like a slew of info resides there but only for Europe. It has accomodation, food & drink, tourist info, entertainment, and historical buildings data. Also included is addresses, telephone numbers to call, and price info on destinations.
Why do we have to start the detour mode at our current location; why can't we set it to begin in X many miles down the road (like the Blaupunkts)?
Why can't we enter latitude & longitude?
Why can't we save our current position, vs. having to save only addresses and intersections?
Why are the disks only 2/3 full (at least in regions 5 & 12)? Others have said that their current disks had less data than the previous version, so that means less detail.

That's a start. I would like to see what others have to say, so let me know what you know/think.
Thanks

I believe there are wheel sensors and a calibration function
 

Someone posted to the VAG-COM list about it once.

The government updated the NAV satellite coverage area thus making the nav more percise for the US..
 

.. was done sometime earlier this year..or late last year.

I don't know about all the other stuff but as for Travel guide.. I don't recall paying attention to that, but I do use the current destination or the destination surroundings to figure out whats in town as far as restaurants and other local places.

Its a nav.. but a crippled version I guess

The real answer...
 

Actually, the government stopped purposely degrading the signal so you get more accurate position estimates. They didn't change the coverage or add satellites (yet).

These systems typically use the ABS as wheel sensors to determine wheel rotation and turning and also tap into the odometer for distance travelled.

Others also uses a compass for a direction.

So, when your vehicle in in a parkade or can't see the sky, the system can still tell you approximately where you are and where you're headed.

Having a digital map available is also a huge help in guessing where you're going with these in car GPS systems.

Andy.