The paper describes the approach of a sensor based landing aid for helicopters in degraded visual conditions. The system concept presented employs a long range high resolution ladar sensor allowing for identifying obstacles in the flight and in the approach path as well as measuring landing site conditions like slope, roughness and precise position relative to the helicopter during long final approach. All these measurements are visualized to the pilot. Cueing is done by 3D conformal symbology displayed in a head-tracked HMD enhanced by 2D symbols for data which is perceived easier by 2D symbols than by 3D cueing. All 3D conformal symbology is placed on the measured landing site surface which is further visualized by a grid structure for displaying landing site slope, roughness and small obstacles. Due to the limited resolution of the employed HMD a specific scheme of blending in the information during the approach is employed. The interplay between in flight and in approach obstacle warning and CFIT warning symbology with this landing aid symbology is also investigated and exemplarily evaluated for the NH90 helicopter which has already today implemented a long range high resolution ladar sensor based obstacle warning and CFIT symbology. The paper further describes the results of simulator and flight tests performed with this system employing a ladar sensor and a head-tracked head mounted display system. In the simulator trials a full model of the ladar sensor producing 3D measurement points was used working with the same algorithms used in flight tests.

Date Published: 16 May 2013
PDF: 15 pages
Proc. SPIE 8737, Degraded Visual Environments: Enhanced, Synthetic, and External Vision Solutions 2013, 87370A (16 May 2013); doi: 10.1117/12.2015753

Published in SPIE Proceedings Vol. 8737:
Degraded Visual Environments: Enhanced, Synthetic, and External Vision Solutions 2013
Kenneth L. Bernier; Jeff J. Güell, Editor(s)