Lasers on planes to prevent fatal crashes
(麻豆淫院) -- A low-cost laser sensor that can quickly and accurately measure the velocity of commercial passenger aircrafts could complement existing sensors and help prevent fatal aeroplane crashes, say University of New South Wales engineers.
Using facilities provided by the Defence Science and Technology Organisation in Melbourne, researchers from UNSW Canberra have developed and successfully tested a proof-of-concept laser-based sensor in a high-speed wind tunnel.
鈥淥ne of the problems with current velocity sensors is that they are susceptible to icing in bad weather,鈥� says Dr Sean O鈥橞yrne from the School of Engineering and Information Technology. 鈥淥ur technology is based on laser light, meaning there are no physical components in the airflow. Instead they are located inside the aircraft where the temperature can be controlled.鈥�
Currently used airspeed sensors 鈥� known as Pitot tubes 鈥� have been considered possible failure points for several fatal aircraft accidents, most recently, , which crashed into the Atlantic Ocean in June 2009.
Accident investigators suspect that a severe storm caused the forward facing pressure holes on the Pitot tube on flight 447 to fill with ice, which prevented the pilots from receiving accurate measurements.
鈥淧itot tubes are simple and reliable instruments, but when they get obstructed, either by ice, dirt build-up, or by birds or insects flying into them, they don鈥檛 tell you your correct speed,鈥� says O鈥橞yrne. 鈥淭hen you need to rely on backup plans, like GPS, which in storm conditions may not do the job.鈥�
鈥淭he technology we have developed measures airspeed like a Pitot tube, but doesn鈥檛 have something poking out into the air. It has a window, which can be built into a recess in the body of the plane, and which can be heated. This also means, in sudden icing situations, it can be kept out of the wind.鈥�
And while it鈥檚 not designed to replace the Pitot tubes entirely, the researchers say it can be used as a low-cost measure to augment the tubes, which will give flight staff more confidence in their readings and help guard against fatal crashes.
O鈥橞yrne says the sensor employs the same technology used in laser computer mice, and measures velocity by using the Doppler shift of the light absorbed by oxygen molecules.
The idea for the sensor was born out of the group鈥檚 work on the SCRAMSPACE project. The next step is to scale down the proof-of-concept into an aircraft-ready design and conduct flight tests.
Provided by University of New South Wales
