In the development of modern automotive safety technologies, the Blind Spot Monitoring (BSM) system has become a critical configuration for enhancing driving safety. It effectively reduces traffic accidents caused by drivers' visual blind spots, providing an additional layer of safety for motorists. As the core technology of blind spot monitoring systems, radar sensing modules play a vital role.
I. Hazards and Current Status of Automotive Blind Spots
During vehicle operation, due to limitations in body structure and the driver's line of sight, there are areas around the vehicle that are difficult for the driver to directly observe—these are known as blind spots. Statistics show that many traffic accidents are related to drivers failing to detect vehicles or obstacles in blind spots in a timely manner. During lane changes or merges, inaccurate awareness of blind spot conditions can easily lead to collisions, posing serious threats to the lives and property of drivers, passengers, and other road users. With the continuous increase in vehicle ownership and the growing complexity of road traffic, effectively addressing automotive blind spot issues has become a key challenge urgently requiring resolution in the automotive industry.
II. Working Principle of Radar Sensing Modules
A radar sensing module is a device that uses radar technology to detect the presence and movement of target objects. In automotive blind spot monitoring systems, millimeter-wave radar sensing modules are commonly used, typically operating at frequencies of 24GHz or 77GHz. Take a 24GHz radar sensing module as an example: it scans the space around the vehicle by emitting high-frequency electromagnetic beams. When electromagnetic waves encounter vehicles, pedestrians, or other obstacles, they reflect back and are received by the radar module. By precisely measuring parameters such as the time difference, frequency difference, and phase difference between the transmitted and reflected waves, the radar sensing module can accurately calculate the distance, speed, and angle of the target object. Meanwhile, using advanced signal processing algorithms, the system analyzes and filters large volumes of reflected signals to identify targets that truly pose a threat to driving safety while excluding interference factors such as stationary roadside objects.
III. Application Methods of Radar Sensing Modules in Automotive Blind Spot Monitoring
(1) Sensor Layout
To achieve comprehensive monitoring of vehicle blind spots, radar sensing modules are typically installed on both sides of the rear bumper. This layout covers a certain range behind the left and right sides of the vehicle, forming an effective monitoring area—generally extending 3–5 meters to the rear sides and 8–10 meters directly behind, with specific ranges varying by vehicle model and system design. In some high-end models, auxiliary sensors are added to the rearview mirrors or door panels to further expand the monitoring range and improve accuracy.
(2) Information Processing and Feedback
Radar sensing modules transmit collected target object data to the vehicle's Electronic Control Unit (ECU). The ECU analyzes this information through complex algorithms to determine whether the target object is in the vehicle's blind spot and whether a potential collision risk exists. Once a vehicle or obstacle is detected approaching the blind spot, the system immediately alerts the driver through multiple channels, such as flashing indicators on the interior rearview mirror, seat vibrations, and audible alarms. When the driver intends to change lanes, if a dangerous situation is detected in the blind spot, the system emits more intense alerts to remind the driver to operate with caution and avoid collisions.
IV. Advantages of Radar Sensing Modules in Automotive Blind Spot Monitoring
(1) Immunity to Light and Weather Conditions
Compared to other visual sensors (such as cameras), radar sensing modules offer significant advantages. They do not rely on light conditions, enabling stable target object monitoring in both strong daylight and harsh weather conditions like nights, rain, and fog. This ensures that automotive blind spot monitoring systems can reliably function in various complex environments, providing continuous safety protection for drivers. For example, in heavy rain, water droplets can blur a camera's vision and degrade visual sensor performance, while radar sensing modules remain unaffected and can still accurately detect vehicles in blind spots.
(2) Precise Distance and Speed Measurement
Radar sensing modules can accurately measure the distance and speed between target objects and the vehicle. Through real-time monitoring of these parameters, the system can accurately determine the movement trends of target objects and predict potential hazards. For instance, when a rear vehicle approaches at high speed, the radar sensing module can quickly detect changes in its speed and promptly alert the driver to pay attention to the rear vehicle's dynamics, enabling reasonable driving decisions. This precise measurement capability provides reliable data support for automotive blind spot monitoring systems, significantly enhancing the accuracy and timeliness of warnings.
(3) High Reliability
As a mature technology, radar sensing modules feature high reliability and stability. Their relatively simple internal structure—lacking complex mechanical components—reduces the likelihood of system failure due to mechanical malfunctions. Additionally, after years of development and optimization, radar sensing modules have significantly improved anti-interference capabilities, effectively resisting interference from other electronic devices and environmental noise to ensure normal operation in various complex electromagnetic environments. This allows automotive blind spot monitoring systems to maintain stable performance over long-term use, providing drivers with reliable safety protection.
