Axes conventions

Mobile objects are normally tracked from an external frame considered fixed.

Finally, attitudes or orientations can be described by a relationship between the external frame and the one defined over the mobile object.

Due to the special importance of international conventions in air vehicles, several organizations have published standards to be followed.

Tait–Bryan angles are often used to describe a vehicle's attitude with respect to a chosen reference frame, though any other notation can be used.

For land vehicles it is rare to describe their complete orientation, except when speaking about electronic stability control or satellite navigation.

If the goal is to keep the shuttle during its orbits in a constant attitude with respect to the sky, e.g. in order to perform certain astronomical observations, the preferred reference is the inertial frame, and the RPY angle vector (0|0|0) describes an attitude then, where the shuttle's wings are kept permanently parallel to the Earth's equator, its nose points permanently to the vernal equinox, and its belly towards the northern polar star (see picture).

(Note that rockets and missiles more commonly follow the conventions for aircraft where the RPY angle vector (0|0|0) points north, rather than toward the vernal equinox).

Aircraft observations are performed downwards and therefore normally NED axes convention applies.

Heading, elevation and bank angles (Z-Y’-X’’) for an aircraft. The aircraft's pitch and yaw axes Y and Z are not shown, and its fixed reference frame xyz has been shifted backwards from its center of gravity (preserving angles) for clarity. Axes named according to the air norm DIN 9300
Representation of the Earth with parallels and meridians
Earth Centered Earth Fixed and East, North, Up coordinates.
RPY angles of cars and other land vehicles
RPY angles of ships and other sea vehicles
RPY angles of airplanes and other air vehicles
Mnemonics to remember angle names
Different reference systems for coordinates in space