Using an airborne CO2 CW laser for free stream airspeed and windshear measurements

Applications of a Laser True Airspeed System (LATAS) in flight are described with examples from trials with an exceptionally reliable and rugged system installed on the HS 125 research aircraft. The LATAS system is briefly described. Its remote sensing capability makes it particularly useful for measuring airflow conditions before they are disturbed by the aircraft. This is demonstrated with results from flight tests of LATAS as a self contained pressure error measurement system (when combined with total pressure and total temperature measurements), and also results from windshear measurements in a severe thunderstorm downburst (microburst). The possible extension of the system to measure turbulence by using a conical scanning beam is described, and several other possible uses such as an airspeed sensor that can discriminate instantaneously between small amplitude gusts and large disturbances for driving an intelligent autothrottle or a combined 3 axis air data and 3 axis ground velocity sensor for helicopters.