Frame Conventions
The reference frame and conventions used in the LRAUV repository follow those on Gazebo. Any data or info that is intended to be used with the LRAUV software needs to make sure to follow these frame conventions. Here we present a summary of those convention but for a full coverage it is encouraged to visit the Gazebo Sim documentation.
Simulation is always performed in Cartesian coordinates (good old XYZ). They correspond to a local tangent plane at a given point on the planetary surface. By default, this plane follows the ENU (East-North-Up) convention, as shown on the image below:
There is support for the use of real world latitude and longitude coordinates in its simulations using the WGS84 geodetic system. In order to use spherical coordinates, Gazebo will project coordinates expressed in the WGS84 frame to Cartesian and back.
Users can define where the origin of the ENU coordinates sits on the surface of the planet in three different ways: through the SDF file, the GUI, or through an Gazebo Transport service call. This tutorial explains the steps needed for the different ways to do so.
Changing the world origin will only affect operations performed afterwards. For example, models already in the world will not be moved when the world origin's coordinates change.