Brief analysis of laser ranging sensor

The laser ranging sensor firstly emits a laser pulse by a laser diode aligned with the target, and the laser is scattered in all directions after being reflected by the target. Part of the scattered light is returned to the sensor receiver, which is received by the optical system and imaged onto the avalanche photodiode. The avalanche photodiode is an optical sensor with an internal amplification function, so it can detect extremely weak optical signals. The target distance can be determined by recording and processing the time elapsed from the time the light pulse is emitted until the return is received.

Laser ranging sensor application:

1. Automobile anti-collision detector: In general, the laser ranging sensor of most existing automobile collision prevention systems uses a laser beam to identify the distance between the target car of the front or rear of the car in a non-contact manner. When the distance between the cars is less than the predetermined safety distance, the automobile anti-collision system performs emergency braking on the vehicle, or issues an alarm to the driver, or comprehensively determines the speed of the vehicle, the distance between the vehicle, the braking distance of the vehicle, the response time, etc. In response, a large number of traffic accidents can be reduced. The advantages of using it on the highway are even more obvious.

2. Vehicle flow monitoring: the use mode is generally fixed to the gantry of high-speed or important intersections. The laser launches and receives the vertical ground downwards, aiming at the middle position of a lane. When the vehicle passes, the laser ranging sensor can output in real time. The relative change in the measured distance value, which in turn depicts the contour of the vehicle being measured. This measurement method generally uses a ranging range of less than 30 meters, and requires a relatively high laser ranging rate, and generally requires 100 Hz. This can achieve good results for monitoring on important road sections. It can distinguish between various types of vehicles. The sampling rate of the body height scanning can reach 10 cm (at a sampling rate of 11 cm at 40 Km/h). The vehicle flow limit, length limit, vehicle classification, etc. can be resolved in real time, and the results can be quickly output.

3. Unmanned aerial vehicles: The rise of new concept systems such as Robot, Drone, unmanned van, and autonomous driving has also stimulated the demand for orbital and obstacle avoidance  technology. Ranging is the basis of obstacle avoidance, and there are a variety of techniques to achieve ranging, including radio frequency , ultrasonic , infrared and laser . Each of these technologies has its own advantages and disadvantages, and the costs are also different.