I'm trying to determine if the XML variables VELOCITY_WORLD X, Y and Z are based on ECEF (Earth Center Earth Fixed) coordinate system. My preliminary testing is showing that they are not. So it makes me wonder what FS is using for a X, Y and Z reference?Thomas

Having another look at the XML_VELOCITY_WORLD variables it looks like:XML_VELOCITY_WORLD_X = longitude in meters per secondXML_VELOCITY_WORLD_Y = altitude in meters per secondXML_VELOCITY_WORLD_Z = latitude in meters per secondMaking them spherical type velocity vector. Without a Cartesian reference they are not linear and do not provide a good platform for mathematics.Does anyone know how to convert them to true XYZ Cartesian based velocity vector, preferably ECEF?Thomas