Radar is at the Heart of New People-Counting Technology

August 06, 2020 by Adrian Gibbons

To monitor building occupancy post-COVID-19, many companies are turning to people-counting systems—with versatile radar technology as the key ingredient.

In 2020, occupancy metrics are no longer a matter of building capacity or efficiency. Instead, it has become a means to limit the number of people in a given space for public safety. To avoid the cost of increased staffing, many companies have turned to automated occupancy technology, like people-counting systems. 

People-counting systems serve two critical functions: 

  1. Detect a person based upon presence, position, and velocity
  2. Provide an output based upon system requirements

When people-counting systems are used for access control, the system can also measure the occupancy of a space and provide instructions to the next customer in line.  At the heart of these occupancy-monitoring devices are radar chips. 

What can engineers expect from such designs as occupancy technology becomes more ubiquitous?


Occupancy Technology

Occupancy technology is not new. Traditionally, it has been used for power efficiency—for instance, to control lighting when everyone leaves a room.

Devices in occupancy technology non-exhaustively include:

  • Passive infrared
  • Ultrasonic
  • Bluetooth
  • Microphonic (audio detection)

Each of these technologies is limited in how well they can detect occupancy when it comes to movement or environmental noise.


Strengths and weaknesses of occupancy sensor technology.

Strengths and weaknesses of occupancy sensor technology. Image used courtesy of Infineon


For instance, PIR does not detect small movements and ultrasonic is affected by the movement of air through a fan. Radar technology transcends these limitations.


Comparing Two Radar Systems: Infineon and TI

As an example of such a radar system in action, Infineon recently announced that the XENSIV 60 GHz radar technology is at the heart of a new, anonymous "smart counter” system. In this use case, the radar systems boast adjustable sensitivity in detection (addressing a PIR limitation) and immunity to environmental factors like noise (addressing an ultrasonic limitation).

Additionally, the radar is not affected by the buildup of dirt and debris or weather effects.


Radar sensor technology monitoring the passage of people and providing traffic information on occupancy

Radar sensor technology monitoring the passage of people and providing traffic information on occupancy. Image used courtesy of Infineon

Texas Instruments also offers people-counting mmWave radar technology using its IWR6843 60-GHz and 64-GHz chipset. This technology processes range, velocity, and angle information with onboard digital algorithms. 


The Issue of Detection Density

Detection density—with fixed azimuth and elevation—is a concern for designers. Radar ranges are limited with these two technologies from Infineon and TI: Infineon’s BGT60TR13C chipset provides 5 m / 90° azimuth / 80° elevation while TI’s IWR6843 chipset offers 15 m / 120° azimuth / 40° elevation.


TI example of a “marked” test environment

TI example of a “marked” test environment, indicating the monitored area using a camera as a reference to compare the radar data. Image used courtesy of Texas Instruments


Because these technologies are directional, other engineering disciplines responsible for building design and utility may face challenges. For radar technology to be effective in a people-counting system, people must be herded through a grid-defined operating path.

Radar technology combined with software ingenuity provides numerous benefits. People-counting technology provides powerful access control schemes, limited only by the density of deployment.


Radar Versatility—Aerospace, Public Health, and Beyond

Radar is a versatile technology ubiquitous across several industries, from aerospace to medical to consumer markets.

Infineon’s XENSIV radar, for example, is being applied to small-scale deployment with contactless blood pressure monitoring and medium-scale deployment for people-counting in public and private buildings.

Radar versatility is a function of frequency and the software architecture tying the hardware together. Higher frequencies allow smaller system integration (think a single chipset) at a lower power profile while software algorithms allow engineers to process information.