Wave-physical factors determining the link quality in ITS-G5 studied with field-operational tests. - In: Focus on linking antennas and propagation with the automotive and 5G industries, (2021), insges. 5 S.
Even though vehicular communication systems have been rolled out in road, they remain a prominent field of research and development. The functional and operational safety of vehicle-to-X system demands reliable and efficient methods for verification and validation, based on their functional principles and underlying wave-physical phenomena. To test such systems in virtual environment, we have undertaken empirical studies of the communication channel, to analyze parameters like distance and sight conditions in a rich multipath environment. This paper describes the results and conclusions derived from a set of field-operational tests along a track, with modules operating with ITS-G5. While the results confirm the expectation that field-operational tests aren't reproducible on a quantitative level, we have gained insight into fundamental constraints on the channel parameters and approaches towards emulation in virtual environment. Employing omni-directional roof-mounted antennas, we have observed reliable communication links for ranges up to 250 meters, independent of sight conditions.
https://doi.org/10.23919/EuCAP51087.2021.9411275
5G mm-wave over-the-air measurements of an agile multi-beam front-end. - In: 2020 50th European Microwave Conference, (2021), S. 153-156
A millimeter wave agile multi-beam front-end with an integrated 4 by 1 antenna array for 5th generation wireless communications is analyzed by antenna and digital communication measurements. The front-end core comprises a compact low-temperature co-fired ceramic multilayer module with a foot-print area of 74 mm × 74 mm. An over-the-air gain of 50.4 dB and a noise figure of 4.9 dB were measured. Link measurements with broadband single-carrier QAM and OFDM signals result in a data rate of 3.2 Gb/s for 400 MHz bandwidth SC-256QAM modulation with 1.2% error vector magnitude of the front-end determined by a detailed analysis.
https://doi.org/10.23919/EuMC48046.2021.9338199
Over-the-air vehicle-in-the-loop test system for installed-performance evaluation of automotive radar systems in a virtual environment. - In: 2020 17th European Radar Conference, (2021), S. 278-281
Automotive millimeter-wave radar systems are key to automated and connected driving technologies. It is necessary to validate their functional performance in the installed state thoroughly, reliably, and efficiently under realistic conditions before deploying them in real-world traffic. Field-operational tests are the ultimate phase of verification and validation of radar sensors. This approach offers the highest degree of realism yet consuming enormous resources and associated risks. Additionally, these drive tests are neither sufficiently reproducible nor controllable. On the other hand, computer simulation-based closed-loop test approaches overcome these limitations, but lack physically realistic environments. Therefore, over-the-air testing approaches have gained great relevance in this context. In earlier work, we proposed an advanced system concept using an over-the-air vehicle-in-the-loop (OTA/ViL) approach for evaluating the installed performance of fully operational automotive radar systems. In this paper, we present the complete test system in a closed loop in a virtual electromagnetic environment with realistic radar target echoes. An exemplary traffic scenario is considered to validate the performance of the implemented test system. Initial measurements provide promising results.
https://doi.org/10.1109/EuRAD48048.2021.00078
Radar target simulator and antenna positioner for real-time over-the-air stimulation of automotive radar systems. - In: 2020 17th European Radar Conference, (2021), S. 95-98
Automotive radar systems in automobiles are key for automated and connected driving. Conventionally, functional tests and safety validation of automotive radar systems are carried out in field-operational tests, but are very resource-expensive and they offer neither reproducibility nor reliability. To improve efficiency and reliability, though at the expense of a partial loss of realism, a controlled test environment is required in which repeatability is guaranteed. We proposed previously a system concept for over-the-air testing of radar systems with a vehicle-in-the-loop approach in a virtual environment. For the test in a controlled environment, a realistic simulation of the radar scenario-under-test is necessary. Technological achievements in hardware, software, and computational power have made powerful radar target simulators and real-time capable control computers available. However, for the spatial degrees-of-freedom, which are key to emulate relevant test cases with dynamic evolution in the virtual environment, the illumination antennas of the radar target simulator must be positioned with high speed, accuracy, and over sufficient angular ranges. This paper describes our hybrid electronic-mechanical antenna positioner, offering three motional degrees-of-freedom. Initial trials with a modern commercially available automotive radar installed in a passenger car are presented and they indicate very promising results.
https://doi.org/10.1109/EuRAD48048.2021.00035
Konzepte für zuverlässige Immissionsmessungen an 5G massive MIMO-Basisstationen. - In: Creating a compatible future, (2020), S. 449-455
https://doi.org/10.15488/10057
Untersuchungen zur korrekten Immissionserfassung von gepulsten Signalen mit dem SRM-3006 am Beispiel von 5G. - In: Creating a compatible future, (2020), S. 465-471
https://doi.org/10.15488/10059
Entwicklung und Verifikation eines Mess- und Bewertungsverfahrens der elektromagnetischen Immission durch ITS-G5. - In: Creating a compatible future, (2020), S. 457-464
https://doi.org/10.15488/10058
Jamming an uncalibrated GNSS array receiver of distributed antenna elements for concealed installation in passenger cars. - In: 2020 European Navigation Conference (ENC), (2020), S. 1-10
Interference signals are a severe threat to any GNSS receiver. Due to the low reception power of satellite signals, even comparably weak interferences can significantly decrease the positioning accuracy of the receiver or lead to a complete signal loss. Therefore, any active interference signal has to be mitigated to ensure a continuous and safe operation. This is especially important in the field of automated driving, where the permanent awareness of a human being is no longer presumed and cars rely solely on GNSS to determine the absolute position necessary for navigation. While uniform rectangular arrays have shown to be the most effective method against interference signals by providing the ability to spatially mitigate incident signals, their size prevents an application in cars produced for the consumer mass market. This paper presents an arrangement, where a set of two distributed linear arrays is used, which seems promising for a concealed installation and allows the application of spatial signal processing algorithms such as beamforming and nulling. Consequences on the positioning accuracy from the joint processing of signals from distributed antenna elements are discussed and the capability to mitigate interference sources is demonstrated.
https://doi.org/10.23919/ENC48637.2020.9317483
Bi-static delay-Doppler reference for cooperative passive vehicle-to-X radar applications. - In: IET microwaves, antennas & propagation, ISSN 1751-8733, Bd. 14 (2020), 14, S. 1749-1757
Automotive radar systems are indispensable for advanced driver assistance systems and traffic safety. Besides existing monostatic radar techniques, bi-static radar sensing like passive coherent location offers additional options to improve the radar visibility of vulnerable road users. Regarding the testing and evaluation of signal processing algorithms including parameter estimation, it is essential to provide electromagnetically shielded and reproducible measurement conditions, in addition to field tests in real traffic scenarios. This study describes the possibility to emulate relevant performance parameters for bi-static radar scenarios in the frequency range from 1 GHz to 6 GHz in a metal-shielded semi-anechoic chamber. Of special interest are the bi-static angle between transmitter, target, and receiver, and the resulting bi-static Doppler frequencies of a realistic vehicular traffic scenario. According to the concept of cooperative passive coherent location, Doppler scattering measurements are presented and compared to electromagnetic simulations. The authors find promising agreement between measured and ground truth data in the delay-Doppler spectrum.
https://doi.org/10.1049/iet-map.2019.0991
Monostatic RCS measurements of representative road traffic objects in the 76 … 81 GHz frequency band. - In: 2020 IEEE Radar Conference (RadarConf20), (2020), insges. 6 S.
https://doi.org/10.1109/RadarConf2043947.2020.9266391