Patent ID: 6564628
Filing Date: 2003-05-20
Classification: G01C

Abstract:
Combined back-up instruments for aircraft delivering indications regarding the conventional speed, the standard altitude and the attitude of the aircraft and accordingly comprising:two pneumatic inlets for measuring pressure, one for the total pressure, intended to be connected up to a total pressure probe mounted on the aircraft, and the other for the static pressure, intended to be connected up to a static pressure probe, an electronic portion for measuring total pressure equipped with an electronic pressure sensor connected up to the pneumatic inlet dedicated to the total pressure, an electronic portion for measuring static pressure equipped with an electronic pressure sensor connected up to the pneumatic inlet for static pressure, an electronic portion for inertial measurements, equipped with gyrometric and accelerometric or inclinometric inertial sensors, an electronic calculator deducing an indication of conventional speed from the total pressure and static pressure information provided by the electronic portions for measuring total pressure and static pressure, an indication of standard altitude from the static pressure information provided by the electronic portion for measuring static pressure and indications regarding the attitude of the aircraft (angle of pitch and angle of roll) relative to a vertical reference direction from the information provided by the electronic portion for inertial measurements, optoelectronic means of display of the indications of conventional speed, of standard altitude and of attitude which are provided by the electronic calculator, these combined back-up instruments being characterized in that the electronic calculator furthermore comprises: electronic means for computing the aerodynamic angle of incidence of the aircraft operating on the basis of the indication of pitch attitude (angle of pitch of the aircraft), of the indication of conventional speed and of the indication of pressure altitude which are delivered by the electronic calculator itself, and electronic means of correcting the static pressure information provided by the electronic portion for measuring static pressure taking into account a correction coefficient dependent on the indication of aerodynamic angle of incidence of the aircraft as delivered by the electronic means for computing the aerodynamic angle of incidence.