A millimetrewave landing aid approach for helicopters under brown-out conditions

Helicopters are essential for any mission of humanitarian or assisting nature in disaster areas. Very often they have to cope with missing infrastructure and extreme environmental conditions. Besides darkness and adverse weather, dust and snow are two of the most dangerous conditions for helicopter landing. At the time being, helicopter pilots have no adequate sensors to get information on height and drift with the necessary precision under dust and snow conditions. Only radar sensors in the microwave or millimetre wave region offer the capability of sufficient transmission through fog, dust and snow. Employing an appropriate signal processing, also the necessary drift information can be extracted from the Doppler shift of the transmitted radar signal. A demonstrator is under development, based upon distributed and netted millimetre wave radar modules, to extract precise height and drift information to be fed into the avionic system of the helicopter and to be used as an aid for landing and take-off during adverse environmental conditions. The paper discusses the design of the broad band miniature millimetre wave radar modules, the design of the broadband high gain antennas and the implementation into the system demonstrator.