During flight, in which frame the ground velocity components are calculated? in the body frame or in the earth frame?
$\begingroup$
$\endgroup$
2
-
3$\begingroup$ If you want ground velocity why would you use anything other than the earth's frame of reference? Nothing else would actually be the ground velocity. $\endgroup$– Notts90Commented Dec 4, 2016 at 12:44
-
2$\begingroup$ @mins that's true, question needs more information I think. $\endgroup$– Notts90Commented Dec 4, 2016 at 13:47
Add a comment
|
2 Answers
$\begingroup$
$\endgroup$
1
The answer is already in the question. Ground speed refers to the ground. That directly implies earth as reference frame.
The speed of an aircraft relative to itself is apparently 0.
-
$\begingroup$ @mins: … and the readings could all be caused by drift while the aircraft is still at rest on the ground. Inertial units are fine for accelerations, but poor for speeds - that is why you still need air data sensors. $\endgroup$ Commented Dec 5, 2016 at 6:52
$\begingroup$
$\endgroup$
The answer to this question lies in what you are trying to evaluate, which is unclear.
Ground velocity could be interpreted to literally "the movement of the ground with respect to the body". In this case the frame origin would be the aircraft (body). Or ground velocity could be interpreted as the velocity of the aircraft with respect to the ground, (frame origin ground). The question is moot for just ground/aircraft or aircraft/ground because one should be the negative/opposite of the other. However, if one is trying to calculate the velocity of one aircraft to the velocity of another aircraft the choice of frame will simplify/reduce the calculations needed to find that value.
