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 signal-detection threshold level, are made. The localization accuracy, resulting from those corrections, is 2.5 cm.

In this paper, a 3D indoor localization demonstrator on the basis of impulse-radio ultrawideband (UWB) technology and time-difference-of-arrival (TDOA) principle is developed and analyzed. The parameters of the transmitter and receiver hardware components are investigated to determine their influence on the localization performance. The signal detection method based on a comparator and the precise time measurement unit was examined. Two effects, namely the threshold-trigger offset and the TDOA variance errors, were quantified. Corrections methods of both these phenomena have been proposed, which delivered very good results in the experiments. With the identified and modeled inaccuracies, the Cramer-Rao lower bound for a 3D TDOA localization system is derived for the first time and verified by measurements, performed in a large-scale industrial environment. The results obtained from measurements follow closely the variance predicted by the CRLB. Moreover, the comparison with the literature published up to date proves the excellent performance of the system presented here.Index Terms-Accuracy, Cramer-Rao lower bound (CRLB), localization, positioning, precision, time-difference-of-arrival (TDOA), ultrawideband (UWB).

In this study, an efficient near‐field imaging system using miniaturised bowtie antennas is proposed for the three‐dimensional (3D) detection of breast tumours. To ensure good penetration and high resolution, a novel compact bowtie antenna is developed. The antenna features a high fractional bandwidth covering both low and high frequencies, while still small in size. A hemispherical array of 16 compact bowtie antennas is built and following a multistatic scenario, scattered signals from two breast phantoms with one and two embedded tumours inside are recorded. The radar‐based set‐up operates in the frequency range of 1.2–7 GHz. It is shown that the imaging system can successfully detect the tumour phantoms in 3D space.

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.

Indoor navigation using inertial sensors with additional radio-signal support is considered in this paper. The experimental results of data fusion between a navigation system, based on inertial measurement unit (IMU) and impulsebased UWB localization system, are presented. The IMU is additionally supported by a pedestrian step length estimations, barometer and electronic compass. The Ultra-Wideband part consists of receiver, carried by the person, and access points distributed in the scenario. The focus of the paper is put on hardware implementation and choice of the optimal data fusion technique. The presented results indicate the clear benefit of tightly coupled navigation filter, where the time differences of arrival of UWB signals are directly processed, without prior calculation of the localization solution.