Maciej Wielgo

35 GHz FMCW drone detection system

This paper presents an experimental system dedicated for the detection and tracking of small aerial targets such as Unmanned Aerial Vehicles (UAVs) in particular small drones (multirotors). The system was proposed in response to increasing drone popularity and the related threats. The hardware and software parts of the system are covered, including the analogue front-end, FPGA based pre-processing and PC based processing, detection and tracking. Real life trials are described with promising results provided. Further research on the subject is proposed.

Multistatic passive radar based on WIFI - Results of the experiment

In this paper results of an experiment using a multistatic passive radar system based on packet wireless network illuminators are presented. The network consists of several transmitters/receivers that operate on the same channel and exchange data with each other. The passive radar listens to the communication and performs decoding of captured frames, and determines the WiFi network node which was the source of the transmitted frame. The received data stream is divided, based upon the decoded source address, into data streams sent by each network node, after which the separated data streams are processed using classical Passive Coherent Localization methods in order to detect target presence and to localize detected targets. The paper presents details of the experiments performed and their results.

Experimental results of DANIEL-35 SAR system tests

This paper presents results of DANIEL-35 Synthetic Aperture Radar (SAR) system tests carried out recently by the Warsaw University of Technology (WUT) together with the Air Force Institute of Technology (AFIT), Poland. The DANIEL-35 system is a high resolution (up to 15cm), compact SAR radar operating in the 35GHz band. The system has been developed under the framework of a μSAR project founded by the Polish National Centre for Research and Development (NCBiR). The goal of this project is to develop a multiplatform SAR system dedicated for ground surface monitoring. The preliminary results obtained from the various system tests, including recent trials where a small plane was used as a radar carrier, are presented in this paper.

The SARENKA SAR system - Experimental results of ISAR imaging

This paper presents the system design, signal processing aspects and measurement results of an experimental Synthetic Aperture Radar (SAR) named SARENKA. The presented system is a C-band radar developed recently at the Warsaw University of Technology. The main goal of this work was to develop a low-cost, small-size and low-weight radar with high resolution dedicated for small aircrafts and medium size unmanned aerial vehicles (UAV). For these purposes the SARENKA SAR system using the Frequency Modulation Continuous Wave (FMCW) concept was designed and tested. The first field tests of the system were done using a cooperative ship on a lake as a target. As a result Inverse SAR (ISAR) images of the target were obtained. In this paper the preliminary results of this experiment are presented and discussed.

Micro-range, micro-Doppler joint analysis of pedestrian radar echo

We present in the paper results of a generalised micro-Doppler analysis that is suited to high range resolution radar. The target echo energy is here represented in the three dimensional space of time, Doppler, and additionally range, what can provide more information on target micro-motion than the standard micro-Doppler analysis which is performed in the time-Doppler plane. The analyzed signals were recorded with a Ka-band FMCW radar of a high 1GHz bandwidth, which could provide good resolution in range, time and velocity. Here, we present a new method to visualize jointly micro-range and micro-doppler effects of a running man observed on the background of ground interferences.

The use of FPGA evaluation board as data acquisition and pre-processing system for Synthetic Aperture Radar

Experiments on Synthetic Aperture Radar require a data acquisition and storage system. Custom-made systems are well suited to this specific application, but the development of such a system is both time and resource consuming. The use of an off-the-shelf FPGA evaluation board with interchangeable analogue to digital converter cards as a data acquisition and pre-processing system was proposed. Such an approach allows not only for operation with different analogue front-ends, but also for the implementation of data pre-processing, such as modulation and decimation. The modulation makes further processing easier and the filtration-decimation reduces the size of the data stream. A complete system was tested thoroughly during a ground-based experiment and is now ready for airborne testing. As there are unused resources in the FPGA, they will be utilized in the future for the implementation of real-time processing.

Doppler only localization in GSM-based passive radar

The localization in a classical multistatic passive radar is based on finding bistatic ellipsoid crossing with at least three pairs of transmitter-receiver. The localization accuracy is dependent on the geometry and bandwidth of the illumination signal. For narrow band signals like GSM cellular phone transmission the bistatic range resolution is very poor, in a range of several kilometers. The paper presents an alternative solution - exploitation of Doppler information and localization based on Doppler-only measurements. Because there were 4 unknowns (in 2-D localization: two spatial and to velocity components) or 6 unknowns (in 3D localization) it is necessary to have at least 4 or 6 bistatic measurements to localized the target. The paper presents the theory of Doppler-only target localization in GSM passive radar, related simulation results and accuracy considerations.

Supersonic target detection in passive radar

The detection of supersonic targets in passive radar is a challenge due to the high speed and acceleration of the targets. In the classical approach, where the crossambiguity function is used, the integration time is limited by the range and Doppler migration. In this paper the application of the extension of the crossambiguity function to the 3-dimensional range-Doppler-acceleration is presented. The target of interest was a supersonic target - a sounding rocket launched by the Student Astronautical Group of the Warsaw University of Technology. As an illumination signal the DVBT-signal was selected.

Doppler-only localization problem solution for PCL radar

The basic method of passive coherent localization takes advantage of TDOA measurements. However, some illuminators of opportunity emit a narrowband signal which makes the resolution of signal arrival time measurements very poor. Then, the Doppler information can be helpful to increase localization precision or provide sufficient information for localization by itself. The paper presents a new, geometry-based method for solving the Doppler-only localization equations in PCL radar multistatic system. The method was implemented and evaluated, and the results are shown.

C-band FMCW radar analog-front-end for SAR/ISAR applications

This paper presents the design and implementation of a C-band Analog-Front-End (AFE) for Frequency Modulated Continuous Wave (FMCW) Radar. This AFE is based on commercial off-the-shelf (COTS) radio frequency components. The system was designed to be used in various radar applications, including short range mode, Synthetic Aperture Radar (SAR) and Inverse Synthetic Aperture Radar (ISAR). The AFE system was designed as a homodyne system, so final applications are based on FMCW radar. Experiments carried out in the laboratory and in the open air environments included moving target detection, ISAR imaging of boats and SAR trails using an airborne platform are presented. The results are discussed keeping in mind a perspective of future work and further improvements.