Piotr Samczynski

Coherent MapDrift Technique

A new parametric autofocus technique with a high accuracy of flight-parameter estimation dedicated to strip-mode synthetic aperture radar (SAR) systems is presented. Most of the known autofocus techniques require high-reflectivity targets (man-made targets) to obtain a properly focused SAR image. The technique proposed in this paper allows flight parameters to be estimated effectively, even for a low-contrast scene (e.g., forests, fields, small paths, etc.). The autofocus technique is based on well-known MapDrift (MD) principles. The presented technique is a coherent one, which allows flight parameters to be estimated more precisely than in the other well-known parametric technique referred to as classical MD. The presented technique allows flight parameters to be estimated with accuracy that is independent of the initial velocity error. It can be used for real-time processing for both Earth imaging and moving-target indication.

DPCA Detection of Moving Targets in Airborne Passive Radar

A new approach to the passive coherent location (PCL) signal processing technique dedicated for use on mobile radar platforms is presented. The main goal of the research conducted was to present different aspects of an efficient space-time ground moving target indication (GMTI) algorithm for PCL radar mounted to airborne platforms. The algorithm described, based on displacement phase center antenna (DPCA), has been successfully tested with simulated and real-life data collected with an airborne passive radar demonstrator (PaRaDe).

Detection of moving targets with multichannel airborne passive radar

Passive radars, i.e., radars that use existing transmitters as illuminators of opportunity, have witnessed a fast progress in the last decade. Recent developments in many countries [1-5] refer to systems that use commercial transmitters (e.g., FM radio, DAB, DVB-T, GSM) and apply advanced signal processing technology to the received signal. The technology, known also by passive coherent location (PCL), is reaching its maturity stage, as some final products appear on the market [6, 7]. Most of these systems are stationary, ground-based passive radars.

mm-Wave SAR demonstrator as a test bed for advanced solutions in microwave imaging

The capability of imaging and surveying ground areas with airborne and spaceborne sensors has a very high priority in many applications, both in the civilian and military sectors. One of the most essential uses of this capability is in disaster monitoring, where up-to-date, reliable images and data are vital for the undertaking and coordinating of rescue actions. Sensors in space are very accurate but typically have a long revisit time, and thus their use for continuous monitoring is limited. Manned aircrafts equipped with optical, infrared, and synthetic aperture radar (SAR) are costly, and their operation in poor weather conditions (like heavy storms) are limited due to concerns over pilot safety. Unmanned aerial vehicles (UAV) are ideal candidates for the safe and cheap surveillance and imaging of such areas. They can provide continuous monitoring at very low cost, be deployed very quickly, and pose no risk of the loss of life in the case of a platform malfunction caused by heavy weather conditions, technical problems, or human error. The disadvantage of small, unmanned platforms is that they only offer limited space for payloads and have a low electrical power supply. This lays down the conditions for the design of an airborne sensor for small- and medium-sized UAVs. The cheapest solution for UAV surveillance is the use of visual light cameras. Optical cameras are cheap, light, and require a low supply of power, but their usage is limited to the daytime and good weather conditions. The presence of heavy rain, clouds, fog, or smoke can significantly reduce their imaging distance, sometimes down to just a few meters. Far better results can be obtained using much longer electromagnetic waves. The use of far infrared (e.g. in the 10 μm region) can provide thermal information and can be used for the detection of people in both day and night conditions, but it does not provide satisfactory images of land and infrastructures. The use of millimeter and centimeter microwaves with active illumination, combined with SAR technology, can provide high resolution images in all weather conditions, day and night, at a distance of several kilometers.

A concept of GSM-based passive radar for vehicle traffic monitoring

In this paper the passive radar used as a transmitter of opportunity GSM BTS stations has been proposed for vehicle traffic monitoring. The paper presents a feasibility study on using GSM signals for traffic control in different environments including urban areas, highways and small agglomeration roads. The initial analysis shows that such system can be successfully used to extract traffic parameters such as the average speed of vehicles and road capacity. Additionally, the presented GSM passive radar concept for vehicle traffic monitoring has been successfully verified using real-life signals recorded during a measurement campaign carried out at the Warsaw University of Technology.

Passive SAR imaging using a satellite pulsed radar as an illuminator of opportunity

This paper presents the analysis and simulation results of a ground stationary passive synthetic aperture radar (SAR) receiver using a spaceborne SAR as an illuminator. In the paper, the bistatic geometry of passive SAR is presented and the expected resolutions are discussed and compared to the monostatic case. Finally, the results of the signal processing for both active and passive SAR imaging are presented. The main goal of the analysis performed was to develop and test new passive SAR algorithms dedicated for the passive SAR receiver developed at the Warsaw University of Technology. The results obtained verify the feasibility of the proposed passive SAR imaging algorithm.

Velocity measurement and traffic monitoring using a GSM passive radar demonstrator

The paper presented an idea for a new potential civilian application for passive radar utilizing a GSM transmitter as the illuminator of opportunity. The concept presented has been verified via the processing of the data recorded during a measurement campaign carried out in a real operational scenario. The results presented in the paper show that a GSM-based PCL system can be used successfully in the future as a new system dedicated to speed control and traffic monitoring, both in urban areas and on small roads and highways. The results presented in the paper show that the system is able to simultaneously distinguish different-sized objects, characterized by different RCSs, as in the example of the truck and cyclist. This result shows the high potential of the proposed system.

The concept of airborne passive radar

This paper presents the concept of an airborne passive radar and the preliminary results of the experiments carried out using two mobile platforms: a car and an aircraft. In the research conducted for the study of this concept, a passive radar mounted to an aircraft was used. The radar utilizes signals transmitted by illuminators of opportunity, e.g. FM radio or DVB-T transmitters. In this way, it is possible for the aircraft to be equipped with a low cost, lightweight, low-power consuming and undetectable radar with a relatively long range. To verify the concept, two experiments with passive radar on a moving platform were carried out. In this paper the results of the experiments are presented, showing the potential of airborne passive radar.

Concept of the Coherent Autofocus Map-Drift Technique

The paper presents concept of the coherent autofocus map-drift technique. The main goal of this work is to obtain high accuracy and sensitivity for autofocus technique in strip-mode SAR. Presented technique is based at the well-known noncoherent map-drift algorithm and it also takes advantages of multi-look registration to estimate unknown platform velocity component. At the proposed coherent map-drift technique, opposite to the classical map-drift, the cross-correlation is not carrying out at the image intensity from multi-look processing, but at the complex multi-look image data.

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.