About getting sensor_msgs/msg/Imu from Pixhawk

I am currently working with Nav2 path learning using Jetson Xavier NX, Holybro Pixhawk 6c and Rplidar S2. I am using ros2 foxy and ubuntu 20.04. The communication between jetson and Pixhawk is done through PX4-Fast RTPS(DDS) Bridge.

I can subscribe and publish uorb topic to the pixhawk properly.

For Nav2, it needs some sensor data for odometry system. Apart from “sensor_msgs/msg/laser” scan from rplidar S2, I need “sensor_msgs/msg/Imu” and “nav_msgs/msg/Odometry” from pixhawk.

There are uorb topics “vehicle_imu” and “vehicle_odometry” from the pixhawk. “vehicle_odometry” is not difficult to be converted into “nav_msgs/msg/Odometry”. However, “vehicle_imu” is totally not matching with “sensor_msgs/msg/Imu”.

I have no idea how to get the “orientation_covariance”, “angular_velocity_covariance” and “linear_acceleration_covariance” from the uorb topics of pixhawk.