Pressure based reference system for aircraft attitude measurement

This paper proposes a new system for aircraft attitude measurements. This measurement system can provide attitude reference measurements, in the other words Euler angles: pitch and roll angles, by a set of modified AHRS units and is aimed for ultra-light category of aircrafts. The principle uses measurement of differential pressure between atmospheric static pressure and reference pressure. The static pressure is measured at tips of aircraft wings by differential pressure sensors with regards to the reference volume. Theory describing behavior of the gas in the closed reference volume is described in the first part of the paper. Two different arrangements of the pressure reference system are described with their advantages and disadvantages. These two arrangements are modeled in Matlab Simulink and various ambient and inner influences are discussed in this part of the paper. Realization of different measurement system arrangements are presented in the next part of this paper. Parameters of the differential pressure sensors for the best performance of pressure based reference system are identified and different methods of data fusion from pressure based measurement system and the one axial accelerometer are described and discussed in the fourth part of this paper. Finally, the results from a roll angle measurement with the help of the pressure based reference system acquired during a test in a wind tunnel are presented and discussed.