what is ultrasonic radar, millimeter wave radar , lidar ?
As cars become more intelligent, their assisted driving becomes more and more advanced. To realize these advanced driving assistance functions, you cannot do without the help of sensor . There are mainly 4 types of car sensors sold on the market. What are the differences in their functions? Which sensor is the best choice? Let's take a look at it together:
01 ultrasonic radar
, as the name suggests, emits ultrasonic waves through the ultrasonic transmitter, and then uses the receiver to receive the time difference of the reflected ultrasonic waves to measure the distance. The main advantages of
: low cost, strong penetrability, waterproof and dustproof. The main disadvantage of
is that it is easily affected by the weather, and the error is large under different weather conditions and vehicle speeds, which is not conducive to long-distance signal propagation. The main scope of use of
: Because of its high detection distance between 0.1-3 meters, it is mainly used for reversing, parking and other functions. That is our common reversing radar.
02 millimeter wave radar
emits radio waves and measures the distance data of the location based on the time difference between receiving the echo and sending it. The main advantages of
: it can work at night, has a long detection range, up to 200 meters, can bypass small obstacles, has strong ability to penetrate fog, smoke and dust, and is installed concealed without affecting the appearance of the vehicle. The main disadvantages of
are: the inability to accurately determine the three-dimensional outline of obstacles, the inability to determine the color of objects, performance degradation in humid environments such as rain and fog, and poor penetration of trees. Generally, it needs to be used in conjunction with a camera. The main scope of use of
:
24GHZ: ACC adaptive cruise, AEB active braking, and collision warning.
77GHZ: Blind spot monitoring, rear cross-travel warning.
03 lidar
target emits and detects laser beam , and then compares the received signal reflected from the target with the transmitted signal. After appropriate processing, relevant information about the target can be obtained, such as target distance, orientation, height, speed, attitude, and even shape and other parameters. The detection range generally does not exceed 150 meters. The main advantages of
: the fastest propagation speed among all radars , high detection accuracy, strong stability, and more accurate recognition of the three-dimensional contours of obstacles. The main disadvantages of
are: it cannot judge color information (such as traffic lights, lane lines, etc.), has poor bad weather effects, cannot bypass obstacle detection, and needs a high-performance processor to process data, which is costly and bulky. The main scope of use of
is similar to millimeter wave radar. The
04 camera
is different from other sensors. It only receives electromagnetic waves and does not send out electromagnetic waves. It can capture surrounding images to identify colors and textures, and can recognize traffic signs, pedestrians, vehicles and other objects through machine learning. The main advantages of
: it can recognize traffic lights, see lane lines clearly, and identify traffic signs, pedestrians, vehicles and other objects. The main disadvantage of
is that the performance is greatly reduced at night and in rainy and foggy weather with poor visibility, making it impossible to accurately identify. The main scope of use of
: lane keeping, traffic sign recognition, active braking, etc... Because of the different physical characteristics of
car sensors, the advantages and disadvantages are also very obvious, so there is no one method that is ideal, but what kind of sensor is more suitable for what scenarios. In order to better provide drivers with safer and more stable driving assistance, the above sensors will often appear in conjunction. Take Lingdu L as an example. The entire car is equipped with 12 millimeter wave radars + 3 millimeter wave radars + 2 cameras for all-round assistance. The advantages and disadvantages of the sensors complement each other to ensure your safe driving.
