In the current context where the automotive industry is continuously moving towards intelligence and safety, radar sensing technology, as a key support in the field of automotive electronics, is playing a crucial and significant role. From various active safety systems that ensure driving safety to the functions of assisted driving that enhance driving convenience, radar sensing technology is ubiquitous, endowing modern vehicles with a more sensitive "perceptual ability".
Analysis of the Basics of Radar Sensing Technology
Radar sensing technology operates based on the principle of electromagnetic wave transmission and reception. The automotive radar system emits electromagnetic waves of a specific frequency into the surrounding environment. When these electromagnetic waves encounter obstacles, they will be reflected, and the reflected waves are captured by the radar receiving device. By accurately measuring the time difference between the transmission and reception of electromagnetic waves and combining it with the propagation speed of electromagnetic waves, the distance between the obstacle and the vehicle can be precisely calculated. At the same time, using the Doppler effect, that is, according to the difference between the frequency of the reflected wave and the frequency of the transmitted wave, the movement speed and direction of the obstacle can be determined. For example, common millimeter-wave radars mostly operate in the frequency bands of 24GHz, 77GHz, or 79GHz. Compared with traditional microwaves, millimeter waves have a shorter wavelength, which makes the radar perform more outstandingly in terms of spatial resolution and measurement accuracy, enabling it to detect target objects more precisely and providing high-quality environmental perception data for automotive electronic systems.
Diverse Applications in the Field of Automotive Electronics
The Core Perception of Advanced Driver Assistance Systems (ADAS)
Adaptive Cruise Control (ACC): In scenarios with good road conditions such as highways, the ACC function greatly enhances the comfort and convenience of driving. The radar sensing system monitors the distance and speed of the vehicle in front in real-time, automatically adjusts the speed of the own vehicle, and maintains a safe following distance. When it detects that the vehicle in front is decelerating, the vehicle automatically reduces its speed; if the road ahead is clear, it can gradually accelerate to the set cruising speed. For example, during a long-distance drive, after the driver activates the ACC function, there is no need to operate the accelerator and brake frequently, reducing driving fatigue.
Automatic Emergency Braking (AEB): This is a crucial safety function that can save lives. The radar continuously scans the area in front of the vehicle. Once it detects a possible collision danger and the driver does not respond in a timely manner, the AEB system quickly intervenes and automatically applies the brakes, causing the vehicle to decelerate or stop emergently, thereby effectively avoiding or reducing the severity of a collision accident. According to statistics, the incidence of rear-end collisions of vehicles equipped with the AEB function is significantly reduced.
Blind Spot Detection (BSD) and Lane Change Assist (LCA): During the driving process of a vehicle, there are blind spots in the driver's field of vision. BSD uses radar sensors to monitor the blind spots on both sides of the vehicle. When a vehicle enters the blind spot, it reminds the driver through in-vehicle visual or auditory warnings to prevent a collision caused by not noticing the vehicle in the blind spot. The LCA function closely cooperates with BSD. When the driver turns on the turn signal to prepare for a lane change, if the system detects that there is a vehicle approaching in the adjacent lane and it is dangerous, it will also issue a warning to ensure the safety of the lane change operation.
The Precise Guidance of the Parking Assistance System
Rearview Radar: When the vehicle is reversing, the traditional rearview radar detects the distance of the obstacles behind through multiple ultrasonic radar sensors at the rear of the vehicle. When the vehicle approaches an obstacle, the frequency of the alarm sound emitted by the sensors gradually accelerates to remind the driver to pay attention to the vehicle distance. With the development of technology, today's rearview radar system can not only provide distance information but also combine with the camera image to present a more intuitive rear environment picture for the driver, assisting in precise parking.
Automatic Parking System: This system integrates multiple radar sensors and cameras to comprehensively perceive the space around the vehicle. The radar is responsible for measuring the size of the parking space, detecting obstacles, and calculating the precise positional relationship between the vehicle and surrounding objects. During the automatic parking process, the vehicle automatically controls the steering, acceleration, and braking according to this data, completing the whole process from finding a parking space to accurately entering the garage, making parking easy and simple. Even novice drivers with insufficient driving experience can easily deal with complex parking scenarios.
The Reliable Guarantee of In-vehicle Safety Monitoring
Monitoring of Left-behind Children and Pets: Millimeter-wave radar can be installed inside the vehicle to monitor the in-vehicle space in real-time. After the vehicle is turned off and locked, if the radar detects the presence of living beings such as children or pets in the vehicle, the system will immediately activate an alarm and notify the vehicle owner through various means such as the vehicle's hazard lights, honking, and mobile phone APP push, preventing children or pets from being left in the vehicle due to negligence and avoiding tragedies.
Driver Status Monitoring: Some high-end vehicle models use radar sensing technology to monitor the driver's vital signs such as heartbeat and breathing, as well as head posture and body movements. Once it detects abnormal states of the driver such as fatigue, distraction, or sudden physical discomfort, it will issue a timely warning to remind the driver to rest or take corresponding measures, effectively preventing traffic accidents caused by the driver's poor state.
Development Trends and Outlook of Challenges
With the acceleration of the process of automotive intelligence and connectivity, radar sensing technology will usher in a broader development space in the field of automotive electronics. On the one hand, the performance of radar is constantly improving. For example, 4D millimeter-wave radars with higher resolution are gradually becoming popular. They can not only detect the distance, speed, and angle of the target but also obtain the height information of the target, providing a more comprehensive and accurate environmental perception for the vehicle. On the other hand, the integration trend of radar with multiple sensors such as cameras and lidars is becoming more and more obvious. Through data fusion, complementing each other's advantages and disadvantages, a more powerful and reliable automotive perception system can be constructed, promoting the development of autonomous driving technology to a higher level.
However, the development of technology is not smooth sailing. Currently, radar sensing technology faces challenges such as cost control, adaptability to complex environments, and signal interference. For example, in adverse weather conditions such as heavy rain and sandstorms, the accuracy of radar signals may be affected; there may also be signal interference problems between the radar systems of different vehicles and with other electronic devices. In addition, the high cost of high-performance radar sensors restricts their widespread application in mid- and low-end vehicle models to a certain extent. In the future, it is necessary for all parties in the industry to cooperate jointly. Through means such as technological innovation and optimization of the production process, the cost can be reduced, and the reliability and stability of the radar in complex environments can be improved, ensuring the continuous and healthy development of radar sensing technology in the field of automotive electronics and providing a solid guarantee for future intelligent travel.
