Helicopters and aircraft in low-level flight have a high risk to strike obstacles, in particular power lines and overhead wires down to the size of telephone wires. This risk increases when flying nap-of-the-earth (N.O.E.), at night and under poor visibility conditions. Existing night vision equipment cannot provide safe detection of these dangerous obstacles. For these reasons there has been, for quite some time, a widely accepted need for reliable means of detecting obstacles, particularly under all acceptable Low-Level and N.O.E. flying conditions. Solutions to this problem, proposed and developed in the past, have been mainly based on millimeter wave technology. More recently, laser based system are being developed which offer good capabilities to solve this task without many of the shortcomings of the radar systems. The laser radar solution, on the other hand, has to prove its adequacy under limited visibility conditions. This paper presents laser radar developments in the thermal infrared (10 micron region) and near infrared spectral regions for helicopter obstacle warning systems. Both Dornier and Eltro have designed, built and demonstrated laser radar sensors for obstacle warning. Eltro has designed and built an experimental laser radar based on CO2-lasers and heterodyne detection. Ranges in excess of 600 m against railway overhead wires and 1100 m against extended targets have been achieved. Dornier has designed, built and flight demonstrated a GaAs laser obstacle warning sensor operating at 0.9 micron. Merits and limitations of these technologies are being discussed.
Laser Based Obstacle Warning Sensors for Helicopters
1995
8 pages
Report
No indication
English
Aeronautics , Infrared & Ultraviolet Detection , Transportation Safety , Air Transportation , Carbon dioxide lasers , Collision avoidance , Gallium arsenides , Heterodyning , Nap-of-the-earth navigation , Navigation aids , Night vision , Optical radar , Radar detection , Remote sensing , Warning systems , Flight tests , Helicopters , Laser targets , Millimeter waves , Near infrared radiation , Performance tests , Spectral bands , Visibility , Foreign technology
Laser Based Obstacle Warning Sensors for Helicopters
British Library Conference Proceedings | 1995
|Laser-based obstacle warning system for helicopters
Emerald Group Publishing | 2006
Hellas: obstacle warning system for helicopters
SPIE | 2002
|Obstacle Detection and Warning System for Helicopters
British Library Online Contents | 2001
|EADS Defence & Security equips NH90 helicopters with obstacle warning systems
Emerald Group Publishing | 2008