Marlene Harter

UWB localization system for indoor applications: concept, realization and analysis

A complete impulse-based ultrawideband localization demonstrator for indoor applications is presented. The positioning method, along with the method of positioning error predicting, based on scenario geometry, is described. The hardware setup, including UWB transceiver and time measurement module, as well as the working principles is explained. The system simulation, used as a benchmark for the quality assessment of the performed measurements, is presented. Finally, the measurement results are discussed. The precise analysis of potential error sources in the system is conducted, based on both simulations and measurement. Furthermore, the methods, how to improve the average accuracy of 9 cm by including the influences of antennas and signaldetection threshold level, are made. The localization accuracy, resulting from those corrections, is 2.5 cm.

24GHz Digital beamforming radar with T-shaped antenna array for three-dimensional object detection

This paper introduces a radar system for three-dimensional (3D) object detection and imaging. The presented 3D measurement method combines the frequency-modulated continuous wave (FMCW) approach for range measurements with a multiple-input multiple-output (MIMO) technique for digital beamforming in two dimensions. With an orthogonal arrangement of the antenna arrays for transmit and receive, the angular information is obtained in azimuth and elevation without mechanical beamsteering. The proposed principle allows performing 3D imaging by means of the acquired range, azimuth, and elevation information with a minimum of required hardware. Starting from the realization of the 3D radar imaging concept, the hardware architecture and the developed prototype are discussed in detail. Furthermore, the object detection capability of the 3D imaging radar system is demonstrated by measurements. The results show that the introduced 3D measurement concept in its realization is well suited for numerous applications.

Simulative Prediction of the Interference Potential Between Radars in Common Road Scenarios

This paper provides qualitative and quantitative values for the received interference power at the antenna ports of automotive radars as well as the probability of their occurrence for actual and future, not yet measurable traffic scenarios on main roads. The influence of the environment, the road traffic behavior, and the radar penetration rate for a defined antenna configuration can be observed. The basis for the analyses are ray-tracing based simulations in order to achieve adequate predictions for the received power levels due to multipaths. The results show that for a radar penetration rate of 100%, the difference between the strongest overall incoherent received interference power level and the level that is received in 90% of the time is up to 7 dB, dependent on the antenna placement and the environment.

Discussion of the operating range of frequency modulated radars in the presence of interference

This paper discusses the operating range of frequency modulated (FM) radars in the presence of interference. For this purpose, radar- and path loss equations are used to draw the equipotential lines for a given signal-to-interference ratio as a function of the spatial distribution of targets and interferers in order to identify relevant scenario constellations. Further the factors influencing the gain of signal versus deterministic interference are discussed based on measurements and simulations. Finally, the influence of different kinds of interference on the spectrum of a frequency modulated continuous wave radar is shown.

Self-Calibration of a 3-D-Digital Beamforming Radar System for Automotive Applications With Installation Behind Automotive Covers

Given the complexity of a radar system with digital beamforming, a number of error influences can appear due to hardware imperfections, temperature drift, and aging. These errors can result in a reduced target detection probability or even lead to false detections. For automotive driver assistance applications, there is a growing demand for hidden integration of radar systems. When installed behind a painted bumper or design radome, additional performance degradation may occur. First, the hardware imperfections according to their appearance in the presented radar system and their effects are analyzed with respect to the angular spectrum estimation. A software-based self-calibration algorithm is proposed and evaluated by means of simulation and measurement. Finally, the extended performance capability of the self-calibration procedure to compensate additional error components from automotive covers is investigated by means of a painted bumper in front of the radar sensor.

Error analysis and self-calibration of a digital beamforming radar system

Given the complexity of a radar system with Digital Beamforming a number of error influences can appear due to hardware non-idealities, temperature drift and aging. These errors can result in a reduced target detection probability or even lead to false detections. According to their appearance in the presented radar system their effects are analyzed with respect to the angular spectrum estimation. A software-based self-calibration algorithm is proposed and evaluated by means of simulations and measurements.

Simulation framework for the estimation of future interference situations between automotive radars

Interference between automotive radar systems is becoming an important topic of research today, since the density of automotive radars is rising continuously. However, the total amount of cars equipped with radar is still below one percent. This paper introduces a method to predict future interference conditions between automotive radars for higher penetration rates and presents selected results.

Detection of Overhead Contact Lines with a 2D-Digital-Beamforming Radar System for Automatic Guidance of Trolley Trucks

The benefit of trolley truck systems is the substitution of the diesel fuel by the cheaper and more ecological electrical energy. Trolley trucks are powered by electricity from two overhead contact lines, where one is the supply and the other the return conductor. Such trolley trucks are used for haulage at open pit mining sites but could also be used for freight traffic at roadways in the future. Automatic guidance prevents the trolley-powered trucks from leaving the track and thus allows higher operating speeds, higher loading capacity, and greater efficiency. Radar is the ideal sensing technique for automatic guidance in such environments. The presented radar system with two-dimensional digital beamforming capability offers a compact measurement solution as it can be installed on top of the truck. Besides the distance measurement, this radar system allows to detect the location and inclination of the overhead contact lines by digital beamforming in two dimensions. Besides automatic guidance, the knowledge of the inclination of the overhead contact lines could allow automatic speed adaption, which would help to achieve maximum speed especially in hilly terrain.