If it possible to change rangefinder's value from mavlink?

ArduCopter Copter 3.4
1

Hi,everyone!
I’m trying to implement terrain follow via SITL.
I found a code in ArduCopter/GCS_Mavlink.cpp
Can I change the rangefinder.distance_cm() and rangefinder.voltage_mv() values to simulate getting data from sensor?
I’ve tried but it seemed not working. Or I did’t know how to verify it.

    #if RANGEFINDER_ENABLED == ENABLED
    void NOINLINE Copter::send_rangefinder(mavlink_channel_t chan)
    {
        // exit immediately if rangefinder is disabled
        if (!rangefinder.has_data()) {
            return;
        }
        mavlink_msg_rangefinder_send(
                chan,
                rangefinder.distance_cm() * 0.01f,
                rangefinder.voltage_mv() * 0.001f);
    }
    #endif
2

Yes but certain conditions, see here for an example:
https://github.com/fnoop/vision_landing/blob/master/vision_landing#L209

This uses the dronekit-python library, btw.