MAVLINK GPS (GPS_TYPE=14) not supported in SITL?

Hey,
I am working on a GPS Denied Navigation algorithm, and want to test a few things in SITL. I am able to send the GPS data to a flight controller (CubeOrange) via pymavlink by setting the GPS_Type = 14, and sending the GPS_INPUT message.

Now, I want to have a test flight for my estimates in SITL. On setting the SIM_GPS_TYPE = 14, it gives an error: “SIM_GPS: No backend for 14”. Is there any way to send GPS via MAVLink in SITL?

Thanks.