Radar sensors facilitate new automotive safety applications

Article By : Niel Smith

New driver and passenger monitoring systems based on radar sensors offer significant functional and safety benefits for in-vehicle systems.

A new generation of powerful RF CMOS smart sensors can be used by automakers and retailers in a wide range of in-vehicle systems, offering attractive features that enhance a car owner’s overall driving experience by detecting approaching objects and monitoring for potential theft.

Figure 1 Radar provides automated recordings of activities surrounding a vehicle. Source: Socionext

Take a theft prevention system, for instance, where radar has the capability to sense suspicious activities entering a near field of a vehicle and then activating the dashcam to initiate recording. The capability can be further extended by using a smart dashcam with built-in artificial intelligence (AI) to analyze a person’s behaviors in real-time and send alerts to car owners with actionable insights.

Figure 2 The pre- and post-collision video recording can serve as proof of evidence for determining incident fault. Source: Socionext

Next, take the case of pre- and post-collision video recording, in which a parked vehicle may be prone to hit-and-run incidents (Figure 2). Conventional camera systems record a collision only after the moment of impact, and often with incremental delay due to power-saving features. But new automotive dashcam systems using radar can detect incoming vehicles and record an incident prior to the occurrence even with the engine turned off. This capability helps to capture and store video footage that may become proof of evidence for determining incident fault.

Figure 3 The dashcam wakes up and gets ready to record when it senses movement near the car. Source: Socionext

The above diagram illustrates the dashcam on standby mode until a movement is detected. The radar module powered by the 24-GHz smart sensor will initiate video recording before an impact takes place. As soon as the system senses movement near the car, the dashcam wakes up and gets ready to record. If an impact is detected, a 20-second video—which can vary depending on system configuration—including 10 seconds before and 10 seconds after the impact is saved.

High-level precision sensing

Then there are 60 GHz smart RADAR sensors aimed at high-level precision sensing for driver-passenger safety and touchless operation. The Socionext’s SC122x series of 60 GHz smart radar sensors offers high-precision sensing for the detection of a person’s location and very minute movements. These capabilities make the sensors ideal for advanced applications such as operating car consoles and infotainment systems using hand motions and gestures.

Furthermore, automotive radar is emerging as a key technology, enabling intelligent and autonomous features in vehicles that help relieve drivers from monotonous tasks, promote driver safety, and add life-saving interventions.

Figure 4 The diagram shows in-cabin driver assistance and safety features. Source: Socionext

Here is a brief description of some of the in-cabin driver assistance and safety features.

Seat occupancy monitoring

This capability identifies the location of passengers and checks passenger safety status, including fastening of seatbelt and airbag activation. These features are beneficial for large capacity passenger vehicles and mass public transportation vehicles such as buses, airplanes, and trains.

Infant and pet detection and fatality prevention

The Federal Communications Commission (FCC) recently granted a waiver to allow in-vehicle radars operating in the 57-71 GHz band to alert a driver if a child is accidentally left unattended in a car. Since radar sensor can be used to detect human presence, as well monitor vital signs such as heartbeat and respiration, the technology is especially significant when infants or pets are left or forgotten in cars. Radar is even more desirable due to its inherent ability to penetrate hard surfaces, since objects such as babies wrapped in blankets may sometimes be hidden from plain sight.

Driver state monitoring

A radar sensor can be used to monitor driver’s vital signs and alert them of changes in their heart rate and rhythm, stress levels, fatigue, respiration, and atrial fibrillation.

Touchless operation

Socionext’s SC1220 sensor offers 3D hand gesture recognition to operate in-vehicle displays and infotainment systems. This feature facilitates enhanced safety without requiring drivers to focus on specific control buttons or dials while driving.

Radar’s merits in automotive designs

Below is a list of radar’s strengths in automotive applications:

  • Radar delivers perception inputs related to range, velocity, and to a limited extent, the boundaries of objects in the vehicle’s surroundings.
  • The accurate velocity determination is considered a key strength of the modality by automotive suppliers.
  • The use of interferometry to determine the range, velocity, and the angular information of objects is considered highly orthogonal—a cost-effective inverse matrix of computation—to the machine vision algorithms used to interpret camera sensor data. When fused with a camera sensor running neural networks, the highly deterministic nature of the radar sensor is considered valuable by autonomous vehicle (AV) software developers.
  • The wavelengths at which automotive radar operates are defined and regulated wavelengths.
  • The widespread adoption of radar technology in the advanced driver-assistance systems (ADAS) market has resulted in robust, reliable, and high-yield manufacturing techniques.
  • The sensor is effective at ranges of more than 200 meters—depending on the field of view (FOV)—and that provides a vital input for systems operating at highway speeds.
  • Radar sensor performs well in poor lighting and weather conditions.

The radar sensing technology is spurring innovations from the automotive industry as the demand for high-precision, multi-functional systems continues to grow. Smart RF sensors provide a wide range of features and benefits, notably in touchless operations, vital signs monitoring, and detection of abnormal occurrences in or surrounding a vehicle. These unique functionalities using radar sensing technology help to improve vehicle occupant safety and enhance a car owner’s overall driving experience.

This article was originally published on Planet Analog.

Niel Smith is a field application engineer at Socionext America.

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