While there is a lot of interest in sensors (3D cameras, Lidar, or Radar) for self-driving vehicles, there is only one sensor which has been used in cars for over 20 years. The sensor has been deployed all over modern vehicles and is probably the one sensor which has contributed most to the safety "smarts" of modern vehicles. It underpins familiar tech like adaptive cruise control and automatic emergency braking. It is reliable and impervious to foul weather; it can see hundreds of meters ahead and can pick out the speed of all the objects it perceives. That sensor is Radar.
This article outlines some of the way in which Radar has been used in automobiles. Radar technology is not limited to vehicles however, high frequency Radar is now available through RadarIQ for integration into a myriad of other applications and projects.
Adaptive Cruise Control (ACC)An Adaptive Cruise Control system is a system that automatically adjusts the vehicle speed to maintain a safe distance from vehicles ahead.
Control is based on sensor information from on-board sensors. These systems typically use a radar sensor which allows the vehicle to gently brake when it detects the car is approaching another vehicle ahead, then accelerate when traffic allows it to.
Adaptive Cruise Control technology is widely regarded as a key component of future generations of intelligent cars. Adaptive Cruise Control significantly impacts driver safety and convenience as well as increasing road capacity by maintaining optimal separation between vehicles and reducing driver errors.
Automatic Emergency Braking (AEB) / Pre-Collision Systems
Automatic emergency braking systems or collision avoidance systems are sophisticated systems which use sensors and computers to anticipate an accident and help avoid bumping fenders or worse. Pre-collision systems involve a small radar detectors near the front of the car, usually within the grill, where it constantly sends out quick bursts of high-frequency radar waves. These waves bounce off the nearest objects and return to the sensor.
If the system detects a potential forward collision either a warning can be displayed to the driver, or the car can take matters into its own hands and apply the brakes on the driver’s behalf. These systems have become so important that they are now mandatory in some countries.
Blind-spot detection (BSD)
The blind spot monitor is a system that detects other vehicles located to the driver’s side and rear and warns the driver (using a combination visual, audible, vibrating, or tactile methods) that there is an obstacle present. They may also include a cross traffic alert which alerts drivers backing out of a parking space when traffic is approaching from the sides. Blind spot detection is made possible with the use of radar mounted near the rear of the vehicle.
Lane-change assist (LCA)
A Lane change assist system comprises a radar sensor on the rear corners of a vehicle. Lane change assist uses radar data to detect vehicles nearby and uses an additional layer of processing to only warn when the driver when changing lanes and there is insufficient space to do so. Radar sensors are used because they don’t have any moving parts and operate in nearly all weather conditions.
Vehicle-Exit Assist (VEA)
Like rear blind spot detection, Vehicle Exit Assist warns the driver or passenger when vehicles or cyclists are approaching from behind as the vehicle doors are opened. If either is detected, the system warns the occupant. While this could often be achieved using several ultrasonic sensors, Radar is a common choice for auto manufactures because the same radar sensor used for blind spot detection or lane sane assist can be used.
Pre-crash warning (PCW)
Pre-crash safety systems detect an imminent crash and deploy safety devices such as seat belt pretensioners. Pre-crash warning systems can take the same data from radar sensors that are already used for adaptive cruise control or automatic braking system and repurpose it to increase vehicle safety.
As you can see, Radar is an incredibly useful, tried and tested sensor for automobiles. Radar sensors for vehicles have typically been very specific and not readily available for other uses. Modern, affordable, mmRadar sensor are now available through RadarIQ for integration into anything from a toy robot to industrial automation.