D. Gromek

Experimental results of the PaRaDe passive radar field trials

In this paper the results obtained during the trials of the PaRaDe (Passive Radar Demonstrator) are presented. The PaRaDe is a passive radar based on FM radio transmitters developed at Warsaw University of Technology. The targets observed during the trials involved highly maneuvering military targets and commercial airliners. The detection results were compared with data acquired with a Mode-S/ADS-B receiver and an active radar.

An Advanced SAR Simulator of Three-Dimensional Structures Combining Geometrical Optics and Full-Wave Electromagnetic Methods

Modern research in the field of synthetic aperture radar (SAR) technology requires intensive simulations. The most accurate solution would be achieved by applying full-wave electromagnetic (EM) simulations. However, such an approach requires extremely huge computational efforts, mainly due to the large dimensions of the considered objects with respect to a wavelength. For that reason, most of currently used radar simulators are based on an optical approach, such as geometrical optics (GO). Full-wave EM methods require much more computational resources and are usually applicable to the analysis of geometries no larger than several wavelengths. Nowadays, standard desktop computer platforms are still equipped with too small computational resources to carry out full-wave EM simulations of large scenes considered in radar applications. This paper presents a new concept of hybrid analysis, based on GO enhanced with full-wave EM simulations of larger facets-of the size of a few radar resolution cells. The SAR raw radar simulator described in this paper allows a complex and realistic simulation of any scene under radar observation to be performed. The scene can be defined using any computer-aided-design software generating digital terrain model (DTM). It also allows using real DTMs gathered with, e.g., light detection and ranging systems.

FMCW SAR based on USRP hardware platform

The paper presents a concept of using universal software radio peripheral (USRP) as a hardware platform for frequency modulation continuous wave (FMCW) synthetic aperture radar (SAR). The concept presented has been successfully verified through several measurements in the laboratory, as well as in real scenarios where the USRP-based SAR radar was mounted on a ground moving platform and SAR images of the surrounding area were created. The results obtained show that USRP hardware can be used successfully in low cost SAR projects, as well as a system for testing FMCW analog front ends. Moreover, due to its small size the proposed system can be used as a direct digital synthesizer (DDS) and analog digital converter (ADC) for low cost systems dedicated for small ultralight aircrafts or medium size unmanned aerial vehicles (UAV).

Experimental Results of Passive SAR Imaging Using DVB-T Illuminators of Opportunity

In this letter, pioneering experimental results of passive synthetic aperture radar (SAR) imaging are presented. The classical active SAR radar operates in monostatic geometry. The SAR sensor presented in this letter is a passive radar utilizing commercial Digital Video Broadcasting-Terrestrial transmitters as illuminators of opportunity. It works in a bistatic configuration, where the receiver is placed on a moving platform and the transmitter is placed on the ground and is stationary. The imaged scenes are stationary surfaces on Earth such as agriculture or urban areas, buildings, etc. In this letter, pioneering results of signal processing verified by a measurement campaign are presented. In the experiment, two synchronized passive radar receivers were mounted on a small airborne platform. The main goal of the presented experiment was to verify the possibility of ground imaging using passive SAR technology and validate previously presented theoretical results.

Ground-based mobile passive imagery based on a DVB-T signal of opportunity

A new approach to passive bistatic radar imaging using DVB-T signals as illuminators of opportunity is presented. The concept has been verified using ground based mobile platforms as a radar receiver carrier. The paper presents an algorithm description and its verification using both simulated and real data gathered during an outdoor measurement campaign.

SAR/ISAR imaging in passive radars

This paper presents a study on the possibility of using Synthetic Aperture Radar (SAR) and Inverse SAR (ISAR) imaging techniques in passive radars, utilizing commercial continuous wave transmitters as illuminators of opportunity. In presenting potential applications of this novel technology, obtainable maximum ranges and resolutions in passive SAR/ISAR technology are discussed. In the paper the main stages of a signal processing chain for SAR/ISAR imaging in passive radar are presented and discussed, showing the challenges and limitations which have to be addressed in designing the passive SAR/ISAR system. Additionally, real SAR and ISAR images obtained by passive radar demonstrators utilizing Digital Video Broadcasting-Terrestrial (DVB-T) illuminators are presented as the proof of concept of the presented technology.

Effective SAR image creation using low cost INS/GPS

In this paper the recent results of Synthetic Aperture Radar (SAR) experiments conducted at the Warsaw University of Technology are presented. In the experiments an SAR radar was mounted on a lightweight airborne platform. The main goal of this experiment was to verify the possibility of obtaining high quality SAR image using navigation data from a low-cost Inertial Navigation System (INS) and classical commercial Global Positioning System (GPS).

Analysis of range migration and Doppler history for an airborne passive bistatic SAR radar

This paper presents an analysis of range migration and Doppler frequency rate-of-change for an airborne passive bistatic radar (PBR) utilizing the synthetic aperture radar (SAR) technique in the imaging of ground objects. The study was carried out for PBR using the Digital Video Broadcasting - Terrestrial (DVB-T) transmitter as an illuminator of opportunity. The results obtained have been verified using both simulated and real data gathered by a PBR mounted on an airborne platform.

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.

Daniel-35 - The concept of multiplatform SAR radar

This paper presents the concept of a new multiplatform Synthetic Aperture Radar (SAR) named Daniel-35 developed by the Warsaw University of Technology together with the Air Force Institute of Technology, Warsaw, Poland. The presented work has been done within the framework of a national μSAR project devoted to the development of a micro SAR radar for ground surface monitoring. The project aims to develop a high spatial resolution (up to 15 cm) SAR system with real-time processing capabilities. The system will be mounted in a universal air platform pod, which allows it to be used by different radar carriers, e.g. small aircrafts, fighters or helicopters. In this paper a new 35 GHz Frequency Modulation Continuous Wave (FMCW) based SAR system developed under the national μSAR project is presented.