This paper presents the pioneering results of successful target detection using a fully operational and cooperative 5G cellular network as a source of illumination in a passive radar system. The electromagnetic wave generated by the real-life base station allowed for remote sensing of a moving car in bistatic geometry, which shows the feasibility of passive radar in which new generation radio networks serve as an illuminator of opportunity. The paper describes passive radar principles, the theoretical fundamentals of the 5G signal structure, and proposed processing for 5G network-based passive radar. Also, the 5G passive radar demonstrator is described, and the trial results showing the possibilities and limitations of using new radio standards in the context of passive radars.

Frequency and Damping Estimation Methods - An Overview: This overview paper presents and compares different methods traditionally used for estimating damped sinusoid parameters. Firstly, direct nonlinear least squares fitting the signal model in the time and frequency domains are described. Next, possible applications of the Hilbert transform for signal demodulation are presented. Then, a wide range of autoregressive modelling methods, valid for damped sinusoids, are discussed, in which frequency and damping are estimated from calculated signal linear self-prediction coefficients. These methods aim at solving, directly or using least squares, a matrix linear equation in which signal or its autocorrelation function samples are used. The Prony, Steiglitz-McBride, Kumaresan-Tufts, Total Least Squares, Matrix Pencil, Yule-Walker and Pisarenko methods are taken into account. Finally, the interpolated discrete Fourier transform is presented with examples of Bertocco, Yoshida, and Agrež algorithms. The Matlab codes of all the discussed methods are given. The second part of the paper presents simulation results, compared with the Cramér-Rao lower bound and commented. All tested methods are compared with respect to their accuracy (systematic errors), noise robustness, required signal length, and computational complexity.

This paper presents an alternative processing chain for the passive radar using fifth-generation (5 G) standard technology for broadband cellular networks as illuminators of opportunity. The proposition is to use a 5 G synchronization signal block's (SSB) periodically transmitted modulated pulse in 5G-based passive coherent location (PCL) system processing. Although the SSB periodicity limits the velocity ambiguity, the paper describes a solution to tackle this problem in a single target scenario. The method is advantageous when there is a lack of transmission in the telecommunication channel, and the 5 G SSB is the only existing signal. The paper proposes a signal processing pipeline for 5G-based PCL that is inspired by passive radars using non-cooperative pulse radar as an illumination source. The method has been validated using simulated and real-life 5 G data measurements. The results presented in the paper show the possibility of detecting a moving target with a lack of data transmission in the 5 G network, using only the SSB when the classical passive radar signal processing fails. The presented results prove the possibility for a significant increase of 5 G network-based PCL utilization in short-range applications.

In recent years, the 5G network has been deployed more and more densely. The signal coverage area is increasing, and in many countries, it allows the use of the new radio (NR) in most large cities. This makes it possible to use 5G network signals for telecommunication and remote sensing purposes. This article describes the opportunities and limitations of using 5G signals for radars. The waveform characteristics of the 5G network were tested and compared, range analyses were made, and the possibilities of detecting targets using impulse signals sent for various purposes in the network were examined. The article presents measurable properties of 5G signals that allow one to detect targets. Also, possibilities of exploiting 5G signalling for radar applications are provided. Moreover, the main limitations of using 5G waveforms and the general 5G architecture for radar purposes are discussed. Finally, a preliminary concept validation is shown with experimental results of car detection using 5G network-based passive radar.

The paper addresses data processing support that is required in capsule gastrointestinal endoscopy. First, capsule position estimation method using standard MPEG-7 image features (descriptors) is discussed. The proposed approach makes use of vector quantization, principal component analysis and neural networks. Next, new algorithms dedicated for virtual colonoscopy (VC) human body inspection are described. The VC images can be registered with endoscopic ones and help in capsule localization and navigation. Finally, an original, low- complexity, efficient image compression method, based on integer-to-integer 4x4 DCT transform, is presented and experimentally verified.

In this paper it is shown that M class PMU (Phasor Measurement Unit) reference model for phasor estimation recommended by the IEEE Standard C37.118.1 with the Amendment 1 is not compliant with the Standard. The reference filter preserves only the limits for TVE (total vector error), and exceeds FE (frequency error) and RFE (rate of frequency error) limits. As a remedy we propose new filters for phasor estimation for M class PMU that are fully compliant with the Standard requirements. The proposed filters are designed: 1) by the window method; 2) as flat-top windows; or as 3) optimal min-max filters. The results for all Standard compliance tests are presented, confirming good performance of the proposed filters. The proposed filters are fixed at the nominal frequency, i.e. frequency tracking and adaptive filter tuning are not required, therefore they are well suited for application in lowcost popular PMUs.