Millimeter-wave Radar Technology:

Protects the Safety of Intersections with a Broader Field-of-view and in Greater Detail

Radar technology, using radio waves to detect vehicles and pedestrians, is expected to improve the functionality of monitoring systems in order to prevent accidents at intersections. Panasonic has developed high-precision and wide-angle-scanning radar technology using high frequency radio waves. This technology can detect objects up to 40 meters away, such as pedestrians and bicycles, separated by as little as 20 centimeters, in only 0.1 seconds. By applying this technology to the 79GHz band of millimeter-wave radar, we can expect the evolution and promotion of traffic safety support systems such as surveillance sensors, to prevent accidents in intersections.

Millimeter-wave radar unit

Photo: Prototype millimeter-wave radar unit (120-degree viewing angle)

Prototype of 120-degree FOV 79GHz radar

Instantly detects approaching cars and people, even in bad weather

79GHz millimeter-wave radar is standardized as high-resolution radar technology (ARIB STD-T111), with a sensor that detects location and speed of objects by measuring the reflection of emitted radio waves.

Compared to other means of detecting obstacles (LIDAR, cameras, etc.), millimeter-wave radar is relatively unaffected by rain, fog, or backlighting, which makes it particularly suitable for low-visibility nighttime and bad weather. This technology is attractive as a means for detecting pedestrians and bicycles.
Utilizing Panasonic's original digital coding technology, this radar technology makes it possible to detect pedestrians or bicycles with a resolution of 20 centimeters, even at a distance of up to 40 meters, in less than 0.1 seconds.

In addition, controlling the interference between multiple pieces of millimeter-wave radar equipment makes simultaneous operation possible, allowing for wide-angle detection. As a result, it will be much easier to choose locations to install the equipment at intersections.

Coded pulse modulation technology, utilizing complementary coding, and multi-dimensional electronic scanning technology

Unlike automobiles, which reflect radio waves strongly from their metal surfaces, highly sensitive detection of less-reflective pedestrians requires some way to reduce the radio wave noise reflected from automobiles. Complementary codes, a type of digital codes used in wireless LAN technology, allow the range side lobes (false image which appear in front of and behind a target's position), which increase the noise level of strong radio wave reflections, to be reduced to be zero in principle. This coded pulse modulation technology, incorporating complementary codes, has been applied to 79GHz radar, which can use bandwidth greater than 1GHz.

With this technology, in addition to the improved sensitivity necessary to detect pedestrians up to 40m way, as well as high dynamic range reflection measurement technology which reduces reflection noise from automobiles to less than 40dB, Panasonic has achieved a distance resolution of 20 centimeters, 2.5 times that of conventional technology. In addition, by utilizing the "Doppler effect," based on the shortening of waves as a source gets closer and the lengthening of waves as it gets further away, it can detect speed with a precision of within 1km/h.

In addition to these highly-sensitive reflection intensity measurement technologies, Panasonic has also developed a new radar signal processing method based on electron beam scanning.
This has enabled the measurement of distance, angle, and speed, independently and in high resolution, allowing for reliable detection of pedestrians and bicycles even right beside automobiles.

Application image using millimeter-wave radar

Application image using millimeter-wave radar (Detection of motorcyclist behind car and pedestrian near road sign)  (Left) Conventional technology: Car and bike are detected as one object, and so are road sign and pedestrian.  (Right) Newly developed technology: Car, bike, road sign and pedestrian are detected as separate objects.

Orthogonal complementary coded modulation technology makes both high-resolution and wide-angle possible at the same time

When multiple pieces of radar equipment use the same frequency band, they create crosstalk (interference with each other), reducing the radar's detection abilities. By applying the orthogonal complementary coded modulation utilized in orthogonal coding technologies such as 3G cellular phones, Panasonic has succeeded in suppressing the crosstalk which arises between multiple pieces of radar equipment by more than 40dB.

Until this technology, a radar system with a detection area of an entire intersection had not been created. However, by staggering multiple millimeter-wave radar detection areas, it is now possible to cover a wide area of over 120° with high precision.

Performance of newly developed millimeter-wave radar technology

Diagram: Wide-angle detection of up to 120 degrees is achieved by operating two radar devices with a viewing angle of less than 60 degrees and by controlling mutual interference. As a result, two persons standing close by can be detected accurately as separate persons (separation ability of 20 cm at a range of 40 m)

Future developments

Panasonic is working alongside supervisory authorities to develop traffic safety support systems which utilize millimeter-wave radar, contributing to the creation of a society with fewer traffic accidents.