Main uses of lidar system

At present, lidar has entered the practical stage in helicopter obstacle avoidance, biological and chemical warfare agent detection, underwater target detection and other military applications are becoming more and more mature.

When a helicopter patrols at low altitude, it is easy to collide with hills or buildings on the ground. Therefore, it is people's dream to develop helicopter airborne radar that can avoid ground obstacles. At present, this radar has been successful in the United States, Germany and France.

The helicopter obstacle avoidance system developed in the United States uses solid-state laser diode emitter and rotating holographic scanner to detect the vast airspace in front of the helicopter, and the ground obstacle information is displayed on the airborne head-up display or helmet display in real time, which plays a great role in ensuring flight safety.

The Hellas obstacle detection laser radar successfully developed by Daimler Benz Aerospace Company in Germany is even better. It is a 1.54 micron solid-state imaging lidar with a field of view of 32 degrees ×32 degrees, and can detect wires with a diameter of 1 cm within a distance of 300-500m. It will be installed in the new EC- 135 and EC- 155.

The podded Clara lidar jointly developed by Dassault Electronics Company of France and Marconi Company of Britain has many functions, using CO2 laser. It can not only detect obstacles such as posts and cables, but also has the functions of terrain tracking, target ranging and indication, moving target indication and so on, and is suitable for airplanes and helicopters.

Chemical warfare agent detection lidar

The traditional chemical warfare agent detection device is carried by soldiers, which advances while detecting, and the detection speed is slow, so soldiers are prone to poisoning.

The KDKHR- 1N long-distance ground laser poison gas alarm system successfully developed in Russia can detect the chemical poison attack in real time, determine the oblique distance, center thickness, height from the ground, center angle coordinates and related parameters of the poison aerosol cloud, and send alarm signals to the automatic control system of the army through wireless channels or wired lines, which has made great progress compared with traditional detection.

The technology of VTB- 1 telemetry chemical warfare agent sensor developed in Germany is more advanced. It uses two 9- 1 1 micron CW CO2 lasers, which can be adjusted at 40 frequencies, and uses the principle of differential absorption spectroscopy to remotely measure chemical warfare agents, which is safe and accurate.

Airborne ocean lidar

The traditional underwater target detection equipment is sonar. Sonar can be divided into active and passive types according to the way of transmitting and receiving sound waves, which can alert, search, characterize and track underwater targets. However, it is very big, weighing more than 600 kilograms, and some even weigh dozens of tons. Lidar uses airborne blue-green laser transmitting and receiving equipment to detect and classify targets under the sea surface by emitting high-power narrow pulse laser, which is simple and accurate.

Up to now, airborne marine lidar has developed three generations of products. The third-generation system successfully developed in 1990s is based on the second-generation system, which adds the functions of GPS positioning and altitude determination. The system interfaces with the automatic navigator to realize the automatic control of route and altitude.

Imaging lidar can detect underwater objects.

ALARMS airborne mine detection system developed by Northrop Corporation of the United States for the Defense Advanced Research Projects Agency of the United States has the functions of automatic real-time detection and three-dimensional positioning with high positioning resolution. It can work 24 hours a day and detect underwater suspicious targets through elliptical scanning.

The airborne underwater imaging lidar successfully developed by Kaman Space Company of the United States is characterized by its ability to image underwater targets. Because each laser pulse of imaging lidar covers a large area, its search efficiency is much higher than that of non-imaging lidar. In addition, imaging lidar can display the shape and other characteristics of underwater targets, and it is easier to identify targets, which is a big advantage of imaging lidar.