Fraunhofer Institute for High Frequency Physics and Radar Techniques FHRModern vehicles are already equipped with numerous sensors that scan the environment and provide valuable data for driver‑assistance functions. For vehicle manufacturers, it is therefore essential to understand how the vehicle’s structural components influence the electromagnetic signals transmitted and received by these sensors. Fraunhofer FHR performs such analyses with high precision — and, for the first time, also computes quantitative information on measurement uncertainty alongside the results.
Without a driver, the vehicle navigates through the streets while the passengers read a book or look at their smartphones — this is the long‑term vision of autonomous driving. A fundamental requirement for this vision is that vehicles must be able to perceive their surroundings at all times and correctly assess potential hazards. This capability is already essential for today’s driver‑assistance systems, which are increasingly integrated into modern vehicles. The basis for such environmental perception is a wide range of sensors: integrated into the vehicle, they detect obstacles on the road and transmit their data to the vehicle control system, which can, for example, initiate a braking maneuver in the event of imminent danger.
Radar sensors use electromagnetic waves to sense their environment. However, these waves do not only propagate through the air until they encounter a potential obstacle — they must also pass through the vehicle components behind which the sensors are installed. Manufacturers therefore want to know: How do vehicle materials, including the various paint layers, influence the electromagnetic waves? How do different painting processes affect the signals?
Analyses…
Fraunhofer FHR conducts such investigations for numerous customers. With its measurement equipment, various types of materials can be professionally measured and characterized — including those composed of multiple homogeneous layers. Two electromagnetic parameters are determined for this purpose. The first is the relative permittivity, which describes how the material interacts with the electric field of the wave. The second is the loss factor, which indicates the attenuation the wave experiences when interacting with the material.
…including measurement uncertainties and standard deviations
A new aspect is that customers will not only receive the measurement results as before, but also quantitative information on measurement uncertainties — specifically, the distribution of the measurement results and the corresponding standard deviation. For customers, this means they can accurately assess the measurement uncertainty, making the results even more concrete and meaningful. They can even combine measurements from multiple laboratories to obtain the best possible estimate of a material’s parameters and their associated uncertainties.
In addition, Fraunhofer FHR has identified elements within the measurement setup that can be further optimized to reduce measurement uncertainty in future iterations.