Originally Posted by
Maninthebar
Could you derive track from heading, speed and acceleration? I think not. Well I couldn't
This is a case in which the difference between theory and practice is greater in practice than it is in theory.
GPS gives you a series of positions. Which means, as theory pedants like me will point out, GPS cannot tell you what your airplane (or ship, or cell phone) is doing in terms of course or velocity
right now, all it can tell you is what your course and velocity were
a little while ago.
But now factor in physics. If your course and velocity were to be
a whole lot different than what they were one second ago, your neck would have snapped from the acceleration. Since your head didn't snap off your shoulders, we can safely infer that your instantaneous velocity vector
right now is
not a whole lot different from what it was
a little while ago.
Factor in reasonable values for
a little while and
a whole lot and you get pretty tight bounds around what your instantaneous course and velocity are.....