Andrzej Lewandowski

Bio: Andrzej Lewandowski is an academic researcher from Wrocław University of Technology. The author has contributed to research in topics: Passive radar & Software-defined radio. The author has an hindex of 2, co-authored 5 publications receiving 10 citations.

A Multichannel Receiver of the Experimental FM Based Passive Radar Using Software Defined Radio Technology

Abstract: In this paper we present results of research on multichannel receiver using Software Defined Radio technology. This receiver is a part of the experimental FM based passive radar being designed. The hardware platform of the receiver consists of the Universal Software Defined Radio Peripheral devices. In the paper we propose modifications of the USRP's FPGA configuration and GNU Radio code. These modifications allow for developing six/nine synchronous input channel receiver based on two/tree USRPs respectively. Issues of synchronization of separate USRP devices by assuring synchronous sampling were presented. We also propose the solution of the problem of the alignment of the data streams being sent from USRP devices via USB to the PC host.

FPGA Implementation of the Gradient Adaptive Lattice Filter Structure for Feature Extraction

Abstract: In this paper evaluation issues of an FPGA implementation of the feature extraction gradient adaptive lattice (GAL) filter are presented. Two different hardware architectures for implementation in the Virtex family of FPGA devices were proposed, namely a single GAL section coprocessor of Virtex PowerPC., and a pipeline architecture. Both of them show significantly higher performance comparing to their software implementation.

Bistatic passive radar simulator with spatial filtering subsystem

Abstract: The purpose of this paper is to briefly introduce the structure and features of the developed virtual passive FM radar implemented in Matlab system of numerical computations and to present many alternative ways of its performance. An idea of the proposed solution is based on analytic representation of transmitted direct signals and reflected echo signals. As a spatial filtering subsystem a beamforming network of ULA and UCA dipole configuration dedicated to bistatic radar concept is considered and computationally efficient procedures are presented in details. Finally, exemplary results of the computer simulations of the elaborated virtual simulator are provided and discussed.

Universal software radio peripheral as a receiver and DSP platform for a passive radar

Abstract: In this paper we discuss the application of the Universal Software Radio Peripheral (USRP) as a multichannel receiver and DSP platform for an experimental multistatic passive radar. We present different approaches to achieve one goal: constructing the multichannel receiver and signal processing platform utilizing USRP devices and software defined radio (GNU Radio) techniques.

Signal receiving and processing platform of the experimental passive radar for intelligent surveillance system using software defined radio approach

Abstract: This document presents a signal receiving and processing platform for an experimental FM radio based multistatic passive radar utilizing Software Defined Radio. This radar was designed as a part of the intelligent surveillance system. Our platform consists of a reconfigurable multi-sensor antenna, radio frequency (RF) front-end hardware and personal computer host executing modified GNU Radio code. As the RF hardware (receiver and downconverter) the Universal Software Radio Peripherals were used. We present and discuss different approaches to construct the multichannel receiver and signal processing platform for passive radar utilizing USRP devices and GNU Radio. Received signals after downconverting on the FPGA of the USRP are transmitted to the PC host where second stage of data processing takes place: namely digital beamforming. Digital beamforming algorithm estimates echo signals reflected from flying target. After estimating echo signals Range-Doppler surfaces can be computed in order to estimate the target position.

A software defined UMTS passive radar demonstrator

Abstract: Passive radar systems, also referred to as Passive Coherent Location systems (PCL), exploit non-cooperative illuminators of opportunity (IO) in order to detect and track targets. Some of the main advantages of such systems with respect to conventional radars include low cost architectures, low energy requirements, the capability of operating without any spectrum resource allocation and a potentially null probability of intercept. In this paper, we introduce a passive radar demonstrator based on the use of UMTS (Universal Mobile Telecommunications System) signals as a source of opportunity. An overview of the UMTS standard and some preliminary measurements are firstly presented in order to verify the suitability of the UMTS waveform for radar applications. Secondly, a low cost software defined experimental radar system is introduced together with a measurement scenario. Finally, some live data detection results are presented and discussed in order to demonstrate the capability of this passive radar system.

Edge detection for pattern recognition: a survey

Abstract: This review provides an overview of the literature on the edge detection methods for pattern recognition that inspire from the understanding of human vision. We note that edge detection is one of the most fundamental processes within the low level vision and provides the basis for the higher level visual intelligence in primates. The recognition of the patterns within the images relates closely to the spatiotemporal processes of edge formations, and its implementation needs a cross-disciplinary approach in neuroscience, computing and pattern recognition. In this review, the edge detectors are grouped in as edge features, gradients and sketch models, and some example applications are provided for reference. We note a significant increase in the amount of published research in the last decade that utilises edge features in a wide range of problems in computer vision and image understanding having a direct implication to pattern recognition with images.

Ambiguity function analysis for passive radar system performance

Abstract: Passive coherent location (PCL) systems can employ a variety of terrestrial broadcast signals for target detection and ranging. Through analysis of the ambiguity function, one can determine a signal's suitability for this application. The main parameters of concern are amplitude, range resolution, Doppler resolution and sidelobe ratios. This paper presents an analysis of several recorded signals in terms of their suitability for PCL. We also discuss the effects of compromise when choosing between performance in range or Doppler resolution, signal processing gain, and surveillance volume.

Edge Detection for Pattern Recognition: A Survey

Abstract: This review provides an overview of the literature on the edge detection methods for pattern recognition that inspire from the understanding of human vision. We note that edge detection is one of the most fundamental process within the low level vision and provides the basis for the higher level visual intelligence in primates. The recognition of the patterns within the images relate closely to the spatiotemporal processes of edge formations, and its implementation needs a crossdisciplanry approach in neuroscience, computing and pattern recognition. In this review, the edge detectors are grouped in as edge features, gradients and sketch models, and some example applications are provided for reference. We note a significant increase in the amount of published research in the last decade that utilizes edge features in a wide range of problems in computer vision and image understanding having a direct implication to pattern recognition with images.