When a GPS unit is set to display NORTH UP, is that True N @ 12 O’clock, or magnetic North @ 12 O’Clock ??
The Real world Garmin Simulator seems to treat North Up as TRUE North Up, and hence the Compass Rose is rotated by the MagVar.
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As Arte Johnson would say “Veeerry Interesting”!
Nice find.
That’s a really good point. Logic would suggest it’s true North as a GPS unit can’t “see” the Earth’s magnetic field AFAIK.
It’s True.
It has the mag-vars in it’s database … only thing the GPS needs to see are the satellites, to get its position.,
That’s a really good question that I’ve never thought about. My guess is it’s true north.
My GUESS would be that the MAP is orientated TRUE North when NORTH UP, and the Compass rose is a Magnetic Compass, correctly orientated by the magvar.
(as depicted by the Garmin Trainer)
Very Interesting, and definitely not schtupid! 
nice “laugh in” reference for us boomers 
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Sock it to me! ----- One ringy-dingy…two ringy-dingies…
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I would guess True North as it relates to the map and aviation charts orientate to True North
The thing is that it can’t though. At least not everywhere. GPS coverage is limited above 70th North and below 70th South. The old INMARSAT consisted of 4 satellites orbiting earth, each taking up some 25% of it in width but they are limited in the length of the beam.
There is (or used to be) a Russian GPS-like system (KOSPARSAT?) for maritime traffic with a satellite covering the poles but they only pass by once every ~4 hours or so.
Disclaimer: That’s what they learned me some 15 years ago at the naval academy. My data may be terribly outdated by now. 
On the more modern airplanes you’ll find a switch saying TRU to change the compass heading to that. So no.
hmmm but on the Garmin is that function not changing the orientation of the map not the compass.
Can’t speak about the Garmin but our Dynon Skyview Is oriented magnetic heading on top. And if mag heading is unavailable (magnetometer failure or discrepancies due to strong disturbances) it shows a notification and displays ground track heading. It doesn’t make much sense that the GTN would display true. It would contradict all other compass roses in the plane and would easily lead to confusing in a stress situation. Most likely it CAN be set to true though.
I have updated the Topic to better represent what this Thread was intended to be about.
The Orientation of the MAP & Compass Rose, as depicted in Garmin GPS systems, in particular the GTN750 in MSFS
.
Garmin Trainer --------------------------------------------------- PMS50 GTN750
- Garmin Trainer has the Compass ROSE orientated to MAGNETIC North
- MSFS GTN750 has the compass rose orientated to True North
Note: In BOTH cases, the Map is orientated to TRUE North (as expected)
Plane is flying 360 Magnetic
What are you talking about? COSPAS / SARSAT are search and rescue satellites in which COSPAS isn’t active anymore, or at least there were talks about retiring the LEO satellites, not sure. GLONASS is the Russian equivalent to NAVSTAR GPS.
Modern aircraft don’t have a “north up” map function other than PLAN mode (which is always orientated to true north) so not relevant in this discussion.
Last one then… Also not true, while IRS / INS systems are usually limited to 70 degrees something N/S, GPS works even at the poles.
On Page 196 of the GTN650 manuel its states the below.
Nav Range Ring
When turned on, the Nav Range Ring option will show a ring with a compass
rose oriented to magnetic north around your present position on the Map page.
On page 189 of the 750 manual its states the below .
Nav Range Ring
When turned on, the Nav Range Ring option will show a ring with a compass
rose around your present position on the Map page.
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