“Cars equipped with high-resolution radar with longer detection range can detect oncoming vehicles faster at longer distances, making lane changes and intersections safer. TI’s corner radar helps automakers meet the latest NCAP safety requirements, creating a safer driving experience around the world.
January 4, 2022
The European New Car Assessment Association (NCAP) recently updated its radar standards to improve driver assistance features in new vehicles.
NCAP standards vary by region; in the United States, NCAP is administered by the National Highway Traffic Safety Administration (also known as NHTSA), while global NCAP is a centralized organization. However, all organizations have a common goal: to set the standard to improve car and driving safety. These organizations provide a 0-5 star rating to help consumers make informed decisions when purchasing a new car.
In many cases, Euro NCAP is the first to set the standard, which in turn drives the development of the global automotive industry. The latest Regulation No. 79 specifies minimum distances and minimum operating speeds for radars in blind spot detection and lane change assist.
For radars, the “Minimum Distance and Minimum Operating Speed” section (Section 184.108.40.206) allows you to find the minimum vehicle operating speed (Vsmin) (the minimum speed that the ACSF Class C function allows to perform a lane change) and what the radar supports Minimum distance (Srear).
In other words, it helps to determine the distance that the blind spot detection radar sensor should detect at a minimum operating speed of 20km/h (with LCM enabled as required by ACSF Class C function).
Improve lane change safety
Safe lane changes allow approaching vehicles enough time to react (slow down), ensuring that a safe driving distance between vehicles is always maintained. Specifically, Regulation R79 (see Section 220.127.116.11) defines the following: If, 0.4 seconds after the start of the lane change, an approaching vehicle in the target lane must decelerate at an acceleration higher than 3m/s² to ensure two If the distance between vehicles is not less than the distance traveled by the ego vehicle within 1 second, the lane change of the ego vehicle is defined as a critical state.
Knowing the distance and speed of the approaching vehicle and the speed of the ego vehicle, the critical distance S between the two vehicles can be calculated at the beginning of the lane changecritical(Section 18.104.22.168.1). If the distance between the two vehicles is less than S at the beginning of the lane changecritical, the lane change is not allowed. Figure 1 shows that Scriticaland ego vehicle speed as a function. Note that the critical distance is closer to 180m when the autonomous vehicle is operating at 20kmph.
Figure 1: Graph of critical distance and speed required to make a safe lane change
Therefore, detecting approaching vehicles and estimating their distances is the key to efficient lane changing. As stated in section 22.214.171.124 of the regulations, each manufacturer must declare the minimum distance (Srear) (regulations require the use of a two-wheeler test Srear). claim-based Srearthis regulation also defines the minimum operating speed (Vsmin), that is, the minimum speed for which the ego vehicle can perform a lane change is calculated. In Figure 2, according to the S that is approaching the vehiclereardistance, its minimum operating speed is 130kmph.
Figure 2: Speed and distance relationship diagram in NCAP regulations (Image source: UN Regulation 79)
For situations where autonomous vehicles cannot detect approaching vehicles in adjacent lanes, the regulation makes the worst-case assumption that in SrearThere is an undetected approaching vehicle at a distance of 130kmph. In this case, it is not allowed to drop below Vsminspeed to change lanes. However, suppose the ego vehicle detects an approaching target vehicle at a distance less than Srearit can be lower than Vsminspeed to change lanes. Provided that this situation is not considered a critical state, i.e. the distance between the approaching vehicle and the ego vehicle is greater than Scritical(as described in section 126.96.36.199.1).
Figure 3: 170m+ motorcycle detection
TI’s AWR2944 is the first single-chip corner radar sensor to help automakers meet the above NCAP safety requirements. The sensor provides excellent angular radar detection performance and integrates 4 transmitters to provide excellent RF performance with 33% higher angular resolution than conventional 3-transmitter devices. Here are the test results for some use cases:
Figure 4: 200m+ vehicle inspection
Meet NCAP requirements with TI mmWave radar sensor for angular radar
Cars equipped with high-resolution radar with longer detection range can detect oncoming vehicles faster at longer distances, making lane changes and intersections safer. TI’s corner radar helps automakers meet the latest NCAP safety requirements, creating a safer driving experience around the world.
The article was co-authored by Adeel Ahmad, Jitendra Gupta, Sandeep Rao and Bhavin Kharadi.
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