Vehicle_global_position in SITL,HITL and normal flight

PX4 Autopilot
1

Hi everyone,

I wanted to know if my understanding of vehicle_global_position and vehicle_global_position_groundtruth is correct.

To my understanding, vehicle_global_position_groundtruth is the topic to which the simulator publishes data in (SimulatorMavlink.hpp)SITL or SIH.

And vehicle_global_position is the topic that the ekf2 publishes to during a normal flight.

Further, I am running HITL for a research project,
in this case mavlink_reciever.cpp handles the MAVLINK_MSG_ID_HIL_STATE_QUATERNION: message by publishing to vehicle_global_position

Does this mean that during HITL, the EKF2 is not used, and no GPS input is evaluated?

Thanks for the help, and please correct me if I am wrong anywhere!