A Vision for Zero Road Fatalities Starts at an ADAS Safety SensorMay 05, 2020 by Gary Elinoff
Vision Zero has set the ambitious goal of zero road fatalities—and ADAS safety may be the key. TI and other suppliers are stepping up with mmWave radar sensors to help.
What's an engineer's role in road safety? A new program, Vision Zero, says that EEs can play an integral part.
Vision Zero urges engineers, traffic planners, policymakers, and public health professionals to rethink road safety, realizing that road errors are inevitable. As such, these professionals should work together to create system designs and road environments that minimize injury or fatalities when these mistakes occur.
US consumer five-star safety ratings and tough European mandates are putting more demands on ADAS to meet this Vision Zero goal. Vehicles must also pass certifications that protect not only their occupants but also address the safety of pedestrians.
These safety efforts hinge on the effectiveness of sensor design in autonomous systems. Several semiconductor suppliers, like Texas Instruments, are rising to meet these stringent requirements with "Vision Zero" as their end goal.
What is Vision Zero?
Vision Zero is an ambitious program that aims to eliminate all traffic fatalities. It is, quite literally, a new vision for safety. Vision Zero recognizes the inevitability of human error and mandates that all stakeholders are responsible for the overall effort of ensuring maximum safety. This includes those designers working at the sensor level of ADAS.
Vision Zero is a new vision for safety. Image used courtesy of Vision Zero Network
Some of the specific parameters to ensure ADAS safety include automatic emergency braking (AEB), autonomous emergency steering (AES), automatic cruise control (ACC), and forward-collision warning (FCW). These systems are only effective insofar as the sensor suite in them is accurate and comprehensive.
Texas Instruments has designed a new front radar millimeter-wave (mmWave) sensor geared to help designers meet these requirements.
A Front Radar mmWave Sensor for Safe ADAS
The AWR2243 is a single chip 76 GHz to 81 GHz frequency modulated continuous wave (FMCW) transceiver. The device features 5 GHz of available bandwidth, four receive channels, and three transmit channels. TX power and RX noise figures are 13 dB and 12 dB, respectively. The unit offers built-in calibration and self-testing.
Basic system diagram for the AWR2243 as applied to short-, medium-, or long-range radar. Image used courtesy of Texas Instruments
Control interfacing to an external processor is accomplished via API or I2C interface. Data interfacing is achieved through mobile industry processor interface (MIPI) D-PHY and CSI2 v1.
To evaluate the AWR2243 and to help designers get products based on it to market faster, Texas Instruments offers the AWR2243BOOST evaluation module.
The AWR2243BOOST. Image used courtesy of Texas Instruments
Texas Instruments also offers the MMWCAS-RF-EVM for the evaluation of designs calling for cascading four AWR2243.
An Improvement from Previous Models
The AWR2243 is the fifth mmWave radar sensor that Texas Instruments has offered. Previous models include:
The first three—AWR1243, AWR 1443, and AWR 1642—featured on-chip memory and on-board R4F MCUs. The new chip, AWR2243, features a maximum real sampling rate of 45 Msps and maximum a complex sampling rate of 22.5 Msps. The corresponding values for the AWR1243 are 37.5 Msps and 18.75 Msps, respectively.
How the New Sensor Advances ADAS
Due to its TX power and RX noise figures, the AWR2243B can sense objects up to a full 220 meters (over 720 feet) away. It can also differentiate between close-by small and large targets. By cascading its multiple receivers and transmitters, it can extend range and enhance resolution.
The unit employs over 2,000 flexible chip modulations enabling features including Doppler division multiple access (DDMA) and beam steering. The beam steering capability enables the sensor to identify vehicles and other objects. A programmable phase shifter has 5.6° resolution.
The AWR2243. Image used courtesy of Texas Instruments
The AWR2243B is ASIL B targeted and is qualified for AECQ100. It is available in a 161-pin 10.4 mm by 10.4 mm flip-chip BGA package.
ADAS Safety Around the Industry
The new front radar mmWave sensor from TI isn't the only device built for ADAS safety. Other manufacturers, like NXP and Calterah are producing similar devices toward this same goal.
Like the AWR2243B, the TEF810X from NXP also operates from 76 GHz to 81 GHz. It features three transmitters and four receivers, and it has a bandwidth of 2 GHz and 4 GHz with chirp switching.
Calterah’s CAL77S244-AE is an automotive-grade radar SoC. It operates from 76 GHz to 81 GHz with up to a 5 GHz sweep bandwidth.
A Collaborative Safety Effort
Vision Zero leaders explain that "In the past, meaningful, cross-disciplinary collaboration among local traffic planners and engineers, policymakers, and public health professionals has not been the norm."
Technology safety plays a vital role in the Vision Zero ethical platform. Image used courtesy of Vision Zero Network
The program seeks to merge the skills of engineers with other roadway stakeholders to support safe mobility, including "roadway design, speeds, behaviors, technology, and policies."
Designers work with the most detail-oriented electrical aspects of a project. But have you had the experience of working on a larger team of professionals, even at a city planning level? If so, share your experience in the comments below.