Automotive radar is a key technology in delivering active safety systems that play a major role in reducing traffic fatalities. Active safety systems include adaptive cruise control and collision warning systems with automatic steering and braking intervention, lane departure warning and electronic stability control. In a collision warning system, the automotive radar consisting of a 77 GHz transmitter emits signals that are reflected from objects ahead, at the side and to the rear of the vehicle and are captured by multiple receivers integrated throughout the vehicle. The radar system can detect and track objects and trigger a driver warning of an imminent collision and initiate electronic stability control intervention.
These active safety systems have been so effective in reducing traffic fatalities that the National Highway Traffic Safety Administration is calling for a mandate that these technologies be included as standard equipment in cars and commercial vehicles.
With the recent addition of the Savant product through the acquisition of Delcross Technologies, ANSYS now has the best-in class simulation tools for the development of automotive radar systems. A major challenge in developing these systems is predicting how radars perform when mounted to electrically large platforms. What is an “electrically large platform”? The platform is basically anything to which an antenna or radar is mounted (e.g., car, ship, airplane, satellite, building, etc.). To be an electrically large platform, it must measure many wavelengths in dimension at the frequency of interest. So, a wide-body airplane at 1 GHz is electrically large and your desk at 60 GHz is also electrically large. The point is that the physical dimensions alone do not determine if the platform is electrically large. Most automotive radars operate near 24 GHz or 77 GHz. A typical car is about 400 wavelengths long at 24 GHz and about 1,300 wavelengths long at 77 GHz. In both cases, the car is definitely electrically large!
These automotive radars are required to operate in complex and dynamic environments where interactions with the host vehicle and the local environment can impact the performance of the radar system. In particular, the material properties of the fascia (i.e., the bumper and grill) and the location of the radar behind the fascia can impact performance. Radar designers and system integrators also need to understand how the radar will perform under varying traffic conditions. As automotive radar systems mature, it is important to understand complex scattering mechanisms in different conditions (e.g., rain, snow, ice, mud, etc.) and for different objects encountered on the roadway.
A challenge with predicting the installed performance of automotive radars is the multi-scale nature of the problem. The radar unit is typically 10’s of wavelengths in dimension with sub-wavelength geometric features. For problems of this size, ANSYS HFSS is the best solution as it very accurately simulates the geometric and material complexities. When the radar unit is mounted into a fascia, the problem size is now 100’s of wavelengths. In this regime, we use a hybrid solution that combines the power of HFSS and Savant. Finally, realistic scenes consisting of other vehicles, pavement and nearby structures are 10,000’s of wavelengths in dimension, which is a perfect problem for Savant. Clearly, multiple computational methodologies are required to address the vast scale of the problem and ANSYS has the best-in-class solutions for this problem.
We are also beginning to explore how to use HFSS and Savant to simulate radar responses for large scenes involving multiple vehicles with changing speed and location. In other words, we are predicting both the location and velocity of other objects on the roadway as seen by the radar mounted in the fascia. This development could introduce revolutionary capabilities for understanding performance of automotive radars in complex, real-world scenarios that are too difficult, too time consuming and too expensive to test.
In the meantime, if you would like to learn more about how ANSYS HFSS and Savant can be used for automotive radar applications, please view this presentation from the 2015 Automotive Simulation World Congress.
We are also hosting a webinar on November 4 entitled “The Best of Both Worlds: Applying ANSYS HFSS and Savant to Simulate Installed Antenna Performance“. The webinar will describe how HFSS and Savant are used together to solve multi-scale installed antenna performance problems. We hope that you will join us.
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