EFFECT OF AN IN-FLIGHT VERTICAL ACCELEROMETER CALIBRATION ON LANDING ACCURACY AFTER BARO-INERTIAL SYSTEM FAILURE

An issue of improving flight safety during landing with an inertial navigation system (INS) and a failed barometric altimeter is considered. In this paper, we propose a specific algorithm for in-flight calibration of the vertical channel of INS. Accordingly, the baro-inertial integration algorithm using a discrete five-state Kalman filter will be performed during a particular flight maneuver before landing. As a result, it is possible to estimate not only the bias of vertical accelerometer but also its scale factor, which is too small to be defined by a usual in-flight calibration algorithm. After applying the proposed algorithm, the flight management system can provide a safe landing with a standalone INS. The algorithm’s performance is assessed by simulating complete mathematical models of aircraft motion and control systems. The impact of calibrated bias and scale factor of vertical accelerometer on the altitude estimation error is provided through an analysis.