Hi fredgrav,
my belief is ... the greater the headwind, the faster the quantity of ram air impacting the tube, the higher the IAS reading, am I right ?!
Are you really asking how an airspeed indicator works?
just to keep energy high in spite of SUDDEN changes in headwind component.
It's the VAPP which is increased by GS mini during these wind gusts. The inertia of the aircraft maintains the present ground speed for a while, which results in an immediate increased airspeed during the gust.