Several common coordinate system and transform the UAV
Coordinate System
In the navigation, guidance and control of unmanned aerial vehicles, often you need to use the following coordinates:
- the geodetic coordinate system (geographic coordinate system),
- the earth-centered earth-fixed (ECEF) coordinate system（ECEF 坐标系），
- the local north-east-down (NED) coordinate system (local coordinate system NED),
- the vehicle-carried NED coordinate system (coordinate system onboard NED),
- the body coordinate system (body coordinate system).
Sometimes used ECIF coordinate system (the earth-centred inertial frame) . Note ECIF and ECEF coordinate differences: ECIF coordinate system is an inertial coordinate system, its x, y-axis with respect to the sun stationary, z-axis only to the earth's north pole; ECEF coordinate system rotating with the Earth, x, y axes in equatorial plane, x-axis pointing to the same earth's north pole, y-axis direction is determined through the prime meridian, z-axis coordinate system is right-handed.
FIG 1 ECIF ECEF coordinate system and the coordinates
It is noted that, due to limitations inherent in the mechanical design of the battery and, usually only a small UAV in a small area at a lower speed flight. Thus, when the conversion between different coordinate systems, some simplifications can be made. For example, in the NED coordinate system and the local coordinate system of the body