optics.org - News - Sensor takes the drag out of flying (June 2004)

6/11/04
"Airspeed measurements are currently made using a number of finger-sized pitot tubes that protrude from the aircraft. They measure airspeed (the speed of the aircraft relative to the surrounding air) by sensing the impact pressure, the difference between static and total pressure. But this well established technology comes at a price. The probes cause drag and with aircraft operating lifetimes estimated at between 20 - 25 years, the associated fuel cost to the airline industry is huge"
It uses doppler shift (like lidar). Unlike other applications, they are trying to increase backscatter. To me, though, SOG (speed over ground) is a little more important and I assume they're using GPS for that. Ships use a pit sword which also creates drag. At the speed they're going, though, perhaps it isn't so important.
(I'm obviously using my new feeds from IOP, thanks guys)