Is it possible to fly a drone which uses Dead reckoning technique of SIRIUS RTK GNSS ROVER(F9P) in tunnel(Environment is out of reach of GNSS)

I have a drone which comes with the pixhawk2(Ardupilot).
I am very interested in Dead reckoning of SIRIUS RTK GNSS ROVER(F9P) and want to fly my drone in tunnel(out of reach GNSS).

If possible, I’d like to buy your SIRIUS RTK GNSS ROVER(F9P) and test the Dead reckonig with my drone.

Please let me know whether a drone which has IRIUS RTK GNSS ROVER(F9P) can fly in the tunnel.