Development of alpha sensor for unmanned aerial systems

An alpha sensor implies an angle of attack sensor to measure the angle between the aircraftpsilas reference line and the relative wind vector to the aircraft. Accurate measurements of AOA (angle-of-attack) are important to identify the aerodynamic coefficients and to evaluate the flight performance of an UAS. For a small scale UAS, AOA is usually estimated by AHRS (attitude heading reference system) combined with an GPS receiver, but this method provides poor information in general. In this paper, a null type alpha sensor developed by aerospace control and system Lab. in Inha University is introduced. The null type alpha sensor has many advantages compared with other kinds of alpha sensors. Most of all it has uniform error characteristics against AOA. And, as the speed increases, the sensor provides more accurate measurements.