Fakulta elektrotechniky a informatiky / Faculty of Electrical Engineering and Informatics
Stálý URI pro tuto komunituhttps://hdl.handle.net/10195/3847
Práce obhájené před rokem 2008 jsou uloženy pouze v kolekci Vysokoškolské kvalifikační práce
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Článekpeer-reviewedpostprint Omezený přístup Road to Repair (R2R): An Afrocentric Sensor-Based Solution to Enhanced Road Maintenance(IEEE (Institute of Electrical and Electronics Engineers), 2023) Jordan, Darryn Anton; Paine, Stephen; Mishra, Amit Kumar; Pidanič, JanPotholes are one of the most important issues in African road-networks. They pose a major threat to mobility and, with time, cause accelerated degradation of the underlying road infrastructure as well as extensive vehicle damage. To address the need for improved infrastructure management, an advanced data gathering solution is required. This paper presents one such solution. The pothole detection, classification and logging (PDCL) system is under active development by Sensorit (Pty) Ltd in collaboration with the University of Cape Town (UCT) Radar Remote Sensing Group (RRSG). This system represents the initial step in Sensorit's modular approach to producing fully autonomous vehicles for African markets. In this paper, an overview of the PDCL system is presented and early results are shown. The efficacy of the system's unique combination of active infrared stereo vision and mmWave frequency-modulated continuous-wave (FMCW) radar sensors is explored. Under various experimental conditions, range-Doppler maps (RDMs) produced by the radar were unable to provide meaningful pothole detections. In contrast, processed depth maps produced by the stereo vision system are demonstrated to successfully detect even shallow potholes.Článekpeer-reviewedpublished Otevřený přístup Simultaneous Optimization of Mismatched Filters and Controlled Amplitude Signals for Long-Range MIMO Radars(IEEE (Institute of Electrical and Electronics Engineers), 2022) Bezoušek, Pavel; Karamazov, SimeonThis study presents a new signal and filter design procedure for long-range multiple-input multiple-output (MIMO) radars with a pulse length shorter than the return time of signals reflected by the most distant targets. The proposed algorithm adopts and radically improves the method of alternating the optimization of filters and signals, which was recently published by the same authors. It introduces full control of the signal envelope variation during the pulse, preserving acceptable peak-to-average power ratio (PAR) and signal-to-noise ratio (SNR) loss values. This state-of-the-art method allows calculation simplicity and is important for high-speed computations in adaptive applications. A gradient algorithm was used for the signal amplitude and phase optimization. The signal amplitude was controlled using a special signal construction consisting of two complex exponentials.Článekpeer-reviewedpublished Otevřený přístup Joint Optimization of Signal Waveforms and Filters for Long-Range MIMO Radars(IEEE (Institute of Electrical and Electronics Engineers), 2022) Bezoušek, Pavel; Karamazov, SimeonThis paper describes a new cyclic algorithm for minimization of signal sidelobes and crosstalk in multiple-input multiple-output (MIMO) radar. The designed algorithm, called SWAP by the authors, is suitable mainly for long-range radars, such as ground-based surveillance, approach, or weather radar. The minimization of energy or amplitude of side lobes, and crosstalk were used as the optimization criteria. The effect of the Doppler shift is also included in the optimization. Although the optimized signals do not maintain a strictly constant envelope, the peak-to-average power ratio (PAR) can be maintained below 1.7. This value is acceptable, especially for radars with modern transmitters based on GaN HEMTs. The algorithm allows for any arbitrary choice of elements weights, enabling the optimization of calculations for a wide range of applications. This paper also presents the results of algorithm testing under various conditions. The designed algorithm makes it possible to suppress the side lobes and crosstalk by up to 20 dB more than the matched filters. These results were achieved at the cost of a slight deterioration in signal-to-noise ratio (SNR) loss (less than 1 dB) and an increase in PAR (up to 2). The resolution of weak close targets is also slightly deteriorated. The algorithm converged quickly, and already after ten or 20 iterations, the results changed only minimally.Článekpeer-reviewedpostprint (accepted) Omezený přístup Application of hash function for generation of modulation data in RadCom system(Elsevier Inc., 2022) Krejčí, Tomáš; Zálabský, Tomáš; Kopecký, Dušan; Trivedi, GauravThe challenge of current radiocommunication systems is the efficient use of the frequency spectrum. One of the rapidly evolving tools is a RadCom system, which combines the functionality of a radar sensor with a communication interface. RadCom systems are used in several fields, and the presented work is focused on their applications in the automotive industry. The goal was to design a modulation technique and generate modulation data, which will be suitable for radar determination of the distance and velocity of targets, but also enable their mutual communication. A model of the RadCom system, which simultaneously allows a simulation of detection and communication of several moving targets, has been developed. Herein, a method of generating pseudo-random data based on the MD5 hashing algorithm is described. The proposed method of radar signal processing enables unambiguous detection of moving targets and determination of the position and velocity of these targets. Principles of synchronization and coding of a radar and communication mode of the RadCom system are explained. A numerical verification of the proposed algorithms using simulation tools is discussed in the final part of the work. The proposed system solution achieves more than 70% probability that the decoded message will not contain erroneous bits.Článekpeer-reviewedpublished version Omezený přístup Statistical Analysis of Ground Clutter from FM Based Passive Radar(Springer, 2019) Bhatta, Abhishek; Pidanič, Jan; Mishra, AmitStatistical characterization of ground clutter information for radar systems is a topic that requires a detailed understanding. In this work, we characterize the ground clutter information from data captured by two Frequency Modulation (FM) based passive radar systems placed at different locations in the Czech Republic. Since the target models are statistically defined by the Swerling models, each of which is based on a particular distribution, we attempted to connect the ground clutter with some of the known distributions. The analysis is performed in three steps. The empirical distribution is fitted with some of the well-known distributions. Two different goodness-of-fit tests (named chi-squared test and Kolmogorov-Smirnov test) are performed on the obtained data by comparing the empirical distribution with the fitted distributions to determine which distribution is the best fit. The observations are analyzed and the results are considered in detail.