What is LIDAR?

Lidar is a radar system that uses a laser beam to detect the target's position, velocity, and other characteristic quantities. Its working principle is to send a detection signal (laser beam) to the target, and then compare the received signal (target echo) reflected from the target with the transmitted signal. After proper processing, the relevant information of the target can be obtained, such as Parameters such as target distance, azimuth, altitude, speed, attitude, and even shape can detect, track, and identify targets such as aircraft and missiles. It consists of a laser transmitter, an optical receiver, a turntable, and an information processing system. The laser converts electrical pulses into light pulses for transmission. The optical receiver then restores the light pulses reflected from the target into electrical pulses and sends them to the display.

LiDAR (Light Detection and Ranging), yes

LIDAR is a collection of laser, global positioning system (

Lidar advantages

Compared with ordinary microwave radars, because lidars use laser beams, the operating frequency is much higher than microwaves, so they bring many advantages, mainly including:

(1) High resolution

Lidar can achieve extremely high angle, distance and speed resolution. Usually the angular resolution is not less than 0.1mard, that is, it can distinguish two targets with a distance of 0.3m at a distance of 3km (this is not possible with microwave radar anyway), and can track multiple targets simultaneously; the range resolution can be Up to 0.lm; speed resolution can reach within 10m / s. High range and speed resolution means that distance-Doppler imaging technology can be used to obtain a clear image of the target. High resolution is the most significant advantage of lidar, and most applications are based on this.

(2) Good concealment and strong anti-interference ability

The laser beam travels in a straight line, has good directivity, and the beam is very narrow. It can only be received on its propagation path. Therefore, it is very difficult for the enemy to intercept it. The laser radar's launch system (transmitting telescope) has a small caliber and a narrow receivable area. The probability of a laser interference signal entering the receiver is extremely low. In addition, unlike microwave radars, which are susceptible to electromagnetic waves widely existing in nature, there are not many signal sources that can interfere with laser radars in nature. The ability to interfere is strong, and it is suitable for working in an increasingly complex and fierce information warfare environment.

(3) Good low-altitude detection performance

Microwave radar has a certain area of blind area (undetectable area) due to the influence of various surface echoes. For lidar, only the irradiated target will reflect, and there is no influence of ground echo, so it can work at "zero altitude", and its low-altitude detection performance is much stronger than microwave radar.

(4) Small size and light weight

Generally, the ordinary microwave radar has a large volume, and the mass of the entire system is measured in tons. The caliber of the optical antenna is several meters or even tens of meters. The lidar is much lighter and smarter. The diameter of the transmitting telescope is generally only centimeters. The minimum mass of the entire system is only tens of kilograms. It is easy to set up and disassemble. Moreover, the laser radar has a relatively simple structure, convenient maintenance, easy operation, and low price.

Disadvantages of Lidar

First, it is greatly affected by the weather and the atmosphere at work. Lasers generally have less attenuation and longer propagation distances in fine weather. In bad weather such as heavy rain, dense smoke, and dense fog, the attenuation increases sharply, and the transmission distance is greatly affected. For example, the CO2 laser with a working wavelength of 10.6 m is better in atmospheric transmission performance among all lasers, and the attenuation in bad weather is 6 times that in sunny days. The working range of the CO2 lidar used on the ground or at low altitude is 10-20km on sunny days, but it is reduced to less than 1 km on bad weather. Moreover, the atmospheric circulation will also cause distortion and jitter of the laser beam, which directly affects the measurement accuracy of the laser radar.

Secondly, because the lidar's beam is extremely narrow, it is very difficult to search for targets in space, which directly affects the interception probability and detection efficiency of non-cooperative targets. It can only search and capture targets in a smaller range, so lidars are rarely alone It is used in battlefield for target detection and search.

Lidar can be divided into pulse lidar and continuous wave lidar according to the working mode. According to different detection technologies, it can be divided into: direct detection lidar and coherent detection lidar. According to the scope of application, it can be divided into: shooting range measurement lidar (Weapon experimental measurement) fire-control lidar (controlling automatic firing and firing of shooting weapons) tracking and identification lidar (guidance, reconnaissance, early warning, underwater target detection), lidar guidance (spacecraft docking, obstacle avoidance), Atmospheric Lidar (cloud height, atmospheric visibility, wind speed, composition and content of substances in the atmosphere). Lidar is mainly used in tracking, imaging guidance, three-dimensional vision systems, wind measurement, atmospheric environment monitoring, active remote sensing and other directions. ^[5]

The laser scanning method is not only the main way to obtain three-dimensional geographic information in the military, but the data obtained through this method is also widely used in resource exploration,

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The traditional underwater target detection device is a sonar. according to

Lidar has the advantages of high precision and high resolution, as well as the prospect of establishing surrounding 3D models. However, its disadvantages are that weak detection of stationary objects such as isolation zones and the current cost of landed technology are high. Lidar can be widely used in ADAS systems, such as adaptive cruise control (ACC), front collision warning (FCW), and automatic emergency braking (AEB). ^[7]