Exploiting Forward Looking Radar Measurements and Digital Map Data Fusion for Altimetry Estimation during Low-altitude Flight

In this paper a sensor fusion algorithm is proposed for an optimal estimation of the Above Runway Level of an aircraft during takeoff or approach, by the combined use in a Kalman filter of Laser Altimeter, GPS, DEMs (Digital Elevation Map) data and ground echoes detected by a forward looking radar. The algorithm was developed in the framework of the nationally funded project TECVOL, a collaboration between Italian Center for Aerospace Researches (CIRA) and the University of Naples (UNINA). The validation of the designed algorithm required the development of orographic trend models, DEMs error model, and a proper improvement of the laser altimeter model previously used in the framework of TECVOL, in order to take into account true terrain elevation. Numerical simulation tests and in-flight data collections have been used to validate the algorithm.