…And then, again I would get (at least) a stable AHRS
Interesting and rather scary that the AHRS depends on GPS in that way. Unfortunately it is a certification requirement that “AHRS” is supplemented by either airdata or GPS, while the old mechanical AI has no such requirement 
Why this is, nobody seems to know.
We have done this before here here here etc.
Historically Aspen used airdata so if the pitot tube froze you lost the whole instrument – a big X. Garmin were not vulnerable to this particular one because they used GPS data (as you have found). But I think Aspen now use GPS too – here presumably because they got a bad name for this.
I can’t think of a solution except an uncertified one which uses triple FOG AHRS and basically simulates a GPS NMEA data stream. Costs a few k though Here and this was one product which now appears gone. They also did a CNS-5000 which was just right. Now you have e.g. this. I was once looking at this, for driving a tablet satnav app and then obviously there is no legality issue. Of course if you are flying in places with GPS jamming then you are there for good reasons and legality is hardly relevant
The remaining problem is that the G1000 will be useless as an attitude presentation, if GPS is being spoofed. So you need a backup attitude instrument; one can use a tablet for displaying that data too (I am not talking about using the internal solid state gyros – those are of little use).
Emir, Can you specify the page number in the G1000 manual where the procedure of turning off the GPS is detailed? Many thanks
It’s in G1000 configuration. Press and hold “Enter” before turning on G1000 and hold it for 3 seconds (or so) and the release it. G1000 will turn on in configuration mode and then you can browse through different pages and configure the system. However, I don’t recommend doing this except if you really know what you’re doing and have appropriate manual.
