“Perimeter monitoring radar” for vehicles that will contribute to the realization of a safe and secure next-generation mobility society
In recent years the auto industry has entered a once-in-a-hundred-years era of great change
“Automatic operation that is safer than human driving.” That is filled with the potential to realize a car society that could be described as the ultimate. Legal and social preparation will be required in parallel, but in technological terms too, various approaches will be required. It is expected that technologies that increase safety with combinations of sensors such as vehicle-mounted radars and cameras will be at the core of advanced driver assistance systems (ADAS).
Example ADAS functions
RCTA（Rear Cross Traffic Alert）
This detects cars approaching from behind when the car is about to back out from its car park.
BSD（Blind Spot Detection）
This detects other cars running parallel in the car’s blind spots.
LCA（Lane Change Assist）
This detects cars travelling faster from behind when changing lanes.
FCTA（Front Cross Traffic Alert）
This detects pedestrians coming from the side when the car is about to come out of an alley.
Furukawa Electric Group’s Furukawa AS succeeded in the development of a “24 GHz perimeter monitoring radar” with global top level detection performance and stability performance, and in 2017, started full-scale mass production of a perimeter monitoring radar in this band as a first for domestic production. In 2019, forward monitoring rather than just the conventional rear monitoring became possible, and the company evolved the radar into a next-generation device combining both performance improvements and smaller size.
Comparison of perimeter monitoring sensors
Apart from radar, cameras, lasers and ultrasonic waves have been applied practically in the past as sensors used for perimeter detection. However, radar is the most suitable as the type of sensor that can be expected to provide stable detection virtually without being affected by solar radiation during the day or night and even in weather conditions such as snow, rain or fog.
|Direct detection of relative velocity||○||×||×||×|
|Weather resistance (fog, rain)||○||△||×||△|
|Nighttime (darkness) capability||○||○||○||△|
○: Suitable △: Usable ×: Not usable
Radar is the most suitable as a sensor for perimeter monitoring applications.
Bands for vehicle-mounted radar and their primary uses
Furthermore, the two main types of band used for vehicle-mounted radar are the quasi-millimeter wave band and the millimeter wave band, but the company advanced development after choosing 24 GHz because of advantages such as weather resistance and mountability.
|Quasi-millimeter wave band||Millimeter wave band|
|Main application||Perimeter monitoring||Front sensing automatic brakes||Perimeter monitoring|
Outstanding breakdown performance
Radar detects the existence of objects as well as the distances to those objects and their relative velocities and angles by irradiating radio waves and receiving the reflected waves from those objects. If there are objects that reflect radio waves strongly like trucks and metal guard rails in the vicinity, the signals received from pedestrians, who are weak reflection objects, are hidden and become difficult to detect, but with the company’s pulse method (Note 1), radar can appropriately detect things like pedestrians and objects moving at low-speed due to its high separation performance.
(Note 1) Pulse method
This is a method that detects distance and relative velocity by sending out pulse waves and detecting the received waves.
Stable detection performance
The radars can be attached inside a vehicle’s bumper bars. There are lots of reflecting objects inside bumper bars and with the conventional frequency modulated continuous wave method (Note 2), detection becomes unstable when the mounting balance shifts due to the shape of the bumpers. However, with the pulse method used by the company’s radar, the received impact is small and targets can be detected.
(Note 2) Frequency modulated continuous wave method: This method sends out frequency modulated continuous waves, with the frequency of the sent waves changed periodically, and because the frequency of the sent wave will have changed at the time the reflected wave from a target is received, it measures that difference in frequency to measure distance.
Kazuyoshi Koizumi of the Technology Department of Furukawa Automotive Systems Inc., which is in charge of target detection algorithms, talked about this as follows.
“The perimeter monitoring radar that we succeeded in commercializing this time is a product that we developed against the backdrop of the know-how and technological capabilities in materials technology, signal transmission technology and high frequency technology that we have developed over many years, ranging from the antennas used for broadcasting from Tokyo Tower and those used in small ETC units, to digital technologies like blind zone countermeasure systems.
Expectations towards the automatic operation of cars have increased more and more. We want to do as much as can be done with radar to enable the realization of a safe and secure automobile society for all related people, including, the people who drive vehicles, their passengers, other vehicles driving in their periphery and pedestrians. In addition, by mounting this radar on forklifts that move around inside factories and warehouses and on the construction machinery at construction and civil engineering sites, we also hope to expand safety and security functions in industrial areas too. “