About coordinates#

What is a “pose”#

What we call a pose is a 6-component vector defining the position (X,Y,Z) and the orientation expressed as intrinsic z-y-x (or extrinsic X-Y-Z) Euler angles of a given point of the space:

  • x

  • y

  • z

  • roll (around x)

  • pitch (around y)

  • yaw (around z)

Here is how angle signs are handled in right-handed coordinate systems.

_images/euler_angles.png

Coordinate systems and units#

Parrot Sphinx relies on with 3 distinct coordinate systems. From the end-user point of view, Gazebo system is the one that is exposed by default.

  • Gazebo

    • Right-handed

    • ENU (East-North-Up)

    • Length unit is meter.

    • Angle unit is rad.

  • Unreal Engine

    • Left-handed

    • ESU (East-South-Up)

    • Length unit is centimeter

    • Angle unit is degree

  • drone firmware

    • Right-handed

    • NED (North-East-Down)

    • Length unit is meter

    • Angle unit is rad

GPS#

_images/coords_enu.png

The origin [X, Y] in any Cartesian frame is generally set by default to the location of Parrot Headquarter, in Paris:

  • latitude: 48.878922°

  • longitude: 2.367782°

Some worlds may implicitly change this location, especially when the scene represents an existing area on the Earth.

It is also possible to customize the GPS coordinates of the origin of the scene, as explained in this section.