The Advanced Driver Assistance System (ADAS), which uses a variety of sensors installed in the car, collects environmental data inside and outside the car at the first time for the identification, detection and detection of static and dynamic objects. Technical processing such as tracking, so that the driver can detect the possible danger in the fastest time, so as to attract attention and improve safety. Active safety technology. The sensors used by ADAS are mainly cameras, radars, lasers, and ultrasonics. They can detect light, heat, pressure, or other variables used to monitor the state of the car. They are usually located in the front and rear bumpers, side mirrors, the interior of the steering column or the windshield On the glass. Early ADAS technology was mainly based on passive alarms. When a vehicle detected a potential danger, it would issue an alert to alert the driver to abnormal vehicle or road conditions. Proactive intervention is also common for the latest ADAS technologies.
This article only describes radar PCBs for automotive applications (see the figure below). Due to the driving of intelligent driving, such PCBs will burst out in large numbers.
The 24GHz radar has a short range, about 5 meters, and there are also improved types. Therefore, 24G millimeter waves are generally installed on the side and rear of the car. Door opening assistance, reverse collision warning mainly.
24G radar PCB sheet: Rogers4835 / 4350B / 4003C
24G radar antenna PCB picture:
The Pcb board is simple and the technology is mature
The 77GHz radar has a long range, about 150-200 meters, and is installed in the front or side of the car. It is generally used for front collision warning, automatic cruise (ACC), intelligent braking (AEBS), and lateral vehicle warning.
PCB sheet: Rogers3003
77G radar antenna PCB picture:
Regardless of whether it is 24G, 77G, 79G, the main focus is on materials. It is best to have a material preparation plan to seize the opportunity.
Advanced driver assistance system (ADAS) application technology
Advanced driver assistance system (ADAS) basic rearview camera
The rear-view camera system can help the driver find objects or people behind the car, so that the car can be reversed and parked smoothly while ensuring safety. A 1-megapixel high dynamic range (HDR) camera is deployed in the advanced system, and cost-effective high-speed Ethernet connection and video compression are achieved through unshielded twisted pair. Other system requirements include proper physical layer interfaces and power. The intelligent rear view camera can analyze video content locally to detect objects and pedestrians. In addition, they support comprehensive local image processing and graphic overlay creation. They are able to measure object distances and trigger braking interventions. This feature helps the driver to safely reverse the car and make it easier for them to park in the parking space. Freescale’s solutions feature high integration and low power consumption, enabling the development of extremely small camera modules. The intelligent rear view camera uses the same interface as the simple analog camera, providing an attractive upgrade path.
Advanced driver assistance system (ADAS) forward looking camera
The camera system in the advanced driver assistance system analyzes video content to provide lane departure warning (LDW), automatic lane keeping assistance (LKA), high / low beam control and traffic sign recognition (TSR). In a forward-looking black-and-white camera, the image sensor provides incoming video frames to a dual-core MCU equipped with a DSP extension for image processing. Other system requirements include the provision of appropriate physical communication interfaces, power supplies, optional DRAM, and embedded flash memory to reduce system costs.
Advanced driver assistance systems are based on different sensor technologies. 77GHz radar sensors have been used in active cruise control systems (ACC) on high-end luxury cars for many years. The system’s sensors can measure the speed of the vehicle in front and the distance between the two vehicles, while monitoring the speed and interval of the own vehicle. Airborne lidar (Lidar) sensors, which have been applied in the mid-range car and economy car markets, are a more economical choice for remote sensors. Compared to radar, this sensor emits laser pulses and can detect light reflected from other objects. The distance from other objects can be calculated by the signal delay time. .
The short-range radar sensor operates at 24 GHz and is used to monitor objects around the vehicle. This sensor is generally installed on the side of the vehicle, and its information is used for blind spot detection (BSD) and parallel line assistance (LCA) functions. For example, when an object appears in the blind spot or a vehicle near the lane enters the blind spot, it will warn the driver. In the next step, its information can be combined with the navigation system to better achieve vehicle guidance. A 24GHz radar sensor installed in front of or behind the vehicle can be used to prevent collisions.
Video sensors can monitor image information such as the size and shape of objects on the sides. Video sensors can monitor other road users, traffic signals, and road signs. The information from the sensors can realize lane departure warning and traffic signal identification functions.
Other infrastructure information such as traffic signals, turns or hillsides can be obtained through maps. Ultrasonic sensors are used in low-speed situations, such as parking, while not requiring a high detection range. And internal data can be collected and provided to other vehicles. Car-to-car communication is used to transmit data to monitor traffic density.
In addition, the data obtained through different sensors can be fused with each other to increase system functions or enhance existing functions. For example, the fusion of radar, cameras, and airborne lidar with navigation data is important to improve vehicle performance. By combining the information from the camera and the map, the recognition rate of the traffic signal identification system can be improved. The detected traffic signals are compared with the data of eHorizon. EHorizon can support the function of ADAS by providing specific information on road infrastructure based on navigation data. Calculating the confidence level determines which traffic signal is displayed to the driver. Fusion of these sensors can also get a new feature, Sensitive Guidance, which is a navigation system with a radar or camera system. The output of the navigation system is adapted to traffic conditions, radar or camera sensors, such as monitoring vehicles in blind spots or other lanes.