In recent years, the automotive industry has made significant strides in sensor technologies to enhance vehicle safety. Among these breakthroughs, the utilisation of 60GHz radar sensors for interior sensing has emerged as a particularly promising innovation. Traditionally employed for external object detection, radar technology has now evolved to address the crucial aspect of in-cabin sensing, specifically targeting the safety of vehicle occupants.
This evolution is primarily driven by the Euro NCAP standards, which prioritise the adoption of new technologies to further enhance occupant safety.
Radar sensors are ideal for interior safety applications because they can penetrate solid materials such as plastic and fabric that would normally obstruct a camera's view. Automotive designers have the flexibility to place radar sensors in various locations within the vehicle without them being obtrusive. By leveraging the capabilities of radar sensors, automobile manufacturers and safety experts are exploring new ways to ensure child safety and provide peace of mind to vehicle owners and occupants alike.
The Solution
Socionext, a provider of advanced semiconductor solutions, has developed the SC1260AR3, an ultra-compact, ultra-low power 60GHz radio-frequency ranging sensor designed specifically for automotive interior applications. This highly integrated device combines antennas and radar signal operation circuits, resulting in maximum detection accuracy within an ultra-low-power and compact package measuring 6x9mm. The SC1260AR3 utilises a wide band of 6.8GHz (57.1 to 63.9GHz) and employs TDM-MIMO operation with an expanded number of receiving antennas for enhanced performance in range-finding and angle calculations.
The SC1260AR3 has many integrated blocks for advanced signal processing. There is the range of FFT which is essential for any further signal processing as well as a CFAR engine for filtering. Then there is signal processing for distance measurement, angle calculation and clustering included. Finally, the output is point cloud data in xyz coordinates. 3D detection zones can be defined to identify presence – and an interrupt notification is generated. All signal processing is completely built-in to the hardware without any need for a CPU or any type of firmware.
Power consumption is an important factor. The antennas and the number of antennas play a significant role in how much power is being used. The SC1260AR3 offers an intelligent power control sequencer giving flexibility to control duty cycle. The average power required is only around 0.72mW at 0.1% duty cycle operation. The sensing operation is running independently without the need for any external CPU interaction.
This device enables easy acquisition of three-dimensional (3D) position information without requiring advanced expertise in high-frequency devices and signal operation. It combines antennas, RF circuits, AD converters, FIFO memory, SPI interface, and intelligent power control sequencer for flexible duty cycle control. This 60GHz radar chip has been specifically designed for a range of Automotive interior sensing applications, with a particular focus on Child Presence Detection and Occupancy monitoring.
Detection and monitoring
Child presence detection technology provides a reliable solution to address incidents where infants or young children are accidentally left inside vehicles, potentially leading to life-threatening situations due to extreme temperatures and lack of ventilation. Radar sensors prove effective in mitigating such risks by accurately detecting the presence of a child within the vehicle, even when obscured from plain sight. These sensors enable timely warnings and alerts to be transmitted to the driver, significantly reducing the likelihood of inadvertent abandonment incidents.
The SC1260AR3 radar chip can detect even the slightest movements, such as breathing or heartbeat. Its ability to penetrate materials makes it suitable for vital sensing, even if a child is wrapped in a blanket or the child seat is covered.
Occupancy monitoring is another critical application for radar sensors, as they can trigger seat belt reminders and airbag deactivation systems. Gone are the days of guesswork in determining occupancy within vehicles. Socionext’s state-of-the-art sensor employs high precision sensing and advanced algorithms to capture real-time occupancy data with exceptional detail. The radar's angular resolution plays a crucial role in accurately identifying the positions of multiple occupants, even when three people are seated in a row. The SC1260AR3's advanced antenna design, featuring 2-Tx and 4-Rx integrated antennas supporting MIMO operation, enables precise occupancy detection and tracking.
Gesture Control
In addition to child presence detection and occupancy monitoring, radar sensor technology can also be used for gesture control and security monitoring. With the ability to recognise 3D hand gestures this radar sensor opens up new possibilities for touchless HMI control especially for managing large displays or rear seat entertainment. The SC1260AR3 utilises point cloud data in XYZ coordinates, making it suitable for touchless gesture detection and control of displays. By matching the trajectory of hand movements with reference data, the radar sensor identifies and recognises various gestures with a high rate of accuracy, eliminating the need for physical contact, enhancing user convenience, improving hygiene and giving seamless and intuitive interactions.
For security monitoring, the radar sensor can trigger an alarm system and activate a camera when suspicious individuals are detected both inside and outside the vehicle. The radar's ability to penetrate materials like glass allows for reliable detection and deterrence of potential threats.
A New Standard
Socionext's radar sensor system sets a new standard in high-precision occupancy monitoring within vehicles. By utilising high-accuracy linear chirp FMCW radar and clustered point-cloud data, the system enables real-time tracking of occupants with exceptional detail. This information provides valuable insights into passenger occupancy, seat belt usage, and overall interior conditions, empowering automakers to make data-driven decisions to enhance safety, comfort, and efficiency.
The radar sensor's low power consumption, even in deep sleep mode (<1mW), makes it suitable for advanced vehicle alarm systems. Its automotive qualification, meeting AECQ100 Grade 2 standards, ensures the system's reliability and adherence to industry requirements for quality and reliability.
Automotive Industry Evolution
As the automotive industry continues to evolve, the integration of radar sensor technology for interior sensing holds immense promise in ensuring the safety and well-being of individuals within vehicles. By effectively addressing the issue of child presence and occupancy detection, we are not only safeguarding innocent lives but also paving the way for a future where advanced sensor technologies enable smarter, safer, and more responsible transportation.
Socionext's 60GHz Radar Sensor with Integrated Antenna-in-Package for Automotive Interior Sensing represents a significant advancement in the industry. Through cutting-edge technology, advanced algorithms, and a highly integrated design, this radar sensor enables automakers to unlock a host of benefits, from optimizing resource allocation to improving passenger experience.
With its exceptional precision and ability to gather valuable insights, vehicle manufacturers can make data-driven decisions, enhance safety, comfort, and efficiency, and pioneer the future of automotive interior sensing.
Author details: Matthias Neumann, Senior Manager Strategic Marketing, Socionext
