Full Physics Simulation Study of Guardrail Radar-Returns for 77 GHz Automotive Radar Systems

Radar is one of the primary active safety sensors for advanced driver assistance systems. Autonomous vehicles will heavily rely on the ability of automotive radar systems to accurately identify crucial targets while filtering out false targets. Road guardrails present a unique corner case challenge to automotive radar sensors due to their large radar cross section (RCS) that can lead to false targets alerts. This paper presents a full physics, full-scale electromagnetic simulation-based study on the radar returns of road guardrails. Results from this paper demonstrate how guardrails can obfuscate crucial targets, such as pedestrians and nearby stationary vehicles. A novel guardrail system for high-pedestrian density areas is proposed. Further RCS reduction of this design is achieved through a proposed diffraction mitigation technique. Simulations using this proposed guardrail system predict over 25-dB reduction in guardrail RCS. Results from this paper show that guardrails with low RCS improve the visibility of adjacent stationary targets, and thus have the potential to reduce accidents and possibly save lives.