"Mxsmanic" wrote in message
...
Ibby writes:

I am quoting from Angle of Attacks comprehensive video guide on the
FMC's POS REF page.
They state that the 'GPS NAV (ENABLE) button (Line Select 5 Right)
toggles the GPS position (default is on) 'as some countries do not
meet certain standards for GPS navigation', 'the GPS will then try to
correct an accurate IRS position with an inaccurate GPS position,
knowing what countries this happens in are part of the NOTAMS that a
pilot would get in his pre-flight with dispatch'. I wasn't aware of
this either so it would need looking into if you're curious

I suspect Angle of Attack (which I have for the 767) has got something
wrong
or isn't stating something clearly. While it is possible to jam GPS
locally,
in the absence of jamming, the accuracy of GPS is the same just about
everywhere, although it declines slightly near the poles (but not over any
specific country).

None of which ever moves in relationship to your basement/flight deck.