Question in fw yaw rate control

Hello guys,

In ecl_yaw_controller.cpp the yaw rate setpoint is computed by:

yaw_rate_setpoint = tan(phi) * cos(theta) * g / airspeed

In my opinion, it should use ground speed instead of airspeed for computing angular velocity of coordinated flight because in winds these two values can be different. I am not sure if I get it right. Are there any specific reason why airspeed is used here?