covariance output(ROS2)

[Aoki-Takanose]

(ROS2 ver) Covariance can be estimated for position_node as well. The details are as follows.

• The covariance is determined by the variation of the GNSS with respect to the vehicle trajectory.
• Covariance estimation is computed when the estimate_status of the position_node is ture.
• In other cases, the covariance is updated using a motion model similar to rtk_deadreckoning.