I was sitting in a traffic jam listening to the radio, soaking in the air conditioning thinking that I was fortunate to be inside of my 991 as opposed to working in the roadway when i wondered if the compass is magnetic or true north?

Yeah, silly question but as an part time astrophotographer I often have to calibrate the difference.

Anyone know?

 

Probably uses traditional sensors to determine magnetic north, then uses GPS coordinates to correct to True North.

 

I don't know for sure, but almost surely it magnetic north.. If for no other reason to be consistent and emulate a traditional compass..

Magnetic north tends to be the accepted standard for most navigation instruments. In the c0ckpit we always reference everything to magnetic north. flight headings and instruments are given in Mag north reference.. runways are indicated as mag north.

That doesn't mean Porsche didn't use True north, but it would be harder to implement and goes against navigation convention..

If it is that the indicator is True north, then it is most likely taken and calculated from the GPS movement directly. But most of the built in navigation systems in cars now have inertial and magnetic references in addition to the GPS so the pointer doesn't point in funny directions when you are moving slow and turning or in a tunnel.

But it does make me want to do an experiment now to find out