This method converts east, north, and up velocity data to a bearing and two speeds.
HRESULT VelocityToBearing( pPNVELBEAR pBearVel, const pPNVELENU pENUVel );
S_OK indicates success. E_INVALIDARG indicates one or more arguments are invalid.
IPosNav::BearingToVelocity, PNVELBEAR, PNVELENU