Real-time estimation of altitude and airspeed under large airflow angles in flight test

Abstract

In the flight test, many test subjects need to enter the large airflow angle. Due to the large airflow angle, the position error of air data sensor is big, and the altitude and airspeed of the aircraft are not accurate, which not only affects the effectiveness of the test results, but also affects the safety of the test flight. This paper proposes two real-time altitude and airspeed estimation methods, including the GPS method and constant wind field method. The GPS method is commonly used in the airspeed calibration, which mainly uses the GPS height change to correct the static pressure, but it depends on the aircraft total pressure sensor to get the airspeed. The constant wind field method directly calculates the true airspeed not depending on the pressure measurement, but it is greatly affected by the wind stability. During the flight test, using this method, the real-time monitoring can provide pilots with accurate altitude and airspeed reference.