Time filter

Source Type

Agency: European Commission | Branch: FP7 | Program: CP | Phase: SEC-2007-3.3-01 | Award Amount: 4.94M | Year: 2009

The project aims to improve the detection of manned and unmanned platforms by exploiting the treatment of more accurate information of cooperative as well as non-cooperative flying objects, in order to identify potentially threats. The scope will be reached by managing the 3D position data in region including extended border lines and large areas, 24 hours a day and in all weather conditions, derived from enhanced existing Primary Surveillance Radar (PSR), together whit conventional data and information coming via various passive radar technique in order to extend the airspace coverage and to enhance the target recognition capability of the surveillance systems. Thus, the security could be enhanced in large areas, at sustainable costs, by improving the recognition of non-cooperative target through more accurate information on its characteristics and/or more accurate positioning. The final objective of the research consists of study, design and realization of a simple demonstrator of a low cost, interoperable, radar based, system able to identify, all kinds of non-cooperative threat with the contribution of data coming from: - an innovative three-dimensional PSR - conventional sensors (Primary radar, Secondary radar, ADBS, etc) - a network composed by a multitude of multi-operational passive, bistatic and high resolution radar. The system core will performs mainly an opportune Fusion of the such data and an accurate control of Consistency enhancing the early warning alerts capacities of final user based on a detailed 3D map of the area under surveillance with additional information on the nature of the target and on the alert level selected considering the track, the direction and a trajectory prediction of the target performed by the included Decision Support module.

Luszczyk M.,Przemyslowy Institute of Telecommunications | Labudzinski A.,Przemyslowy Institute of Telecommunications
Proceedings International Radar Symposium | Year: 2012

The mostly applicable radar signal is pulse signal with linear frequency modulation (LFM). The main feature such signal is time-bandwidth product (so called base) which is calculated as product of pulse duration and signal bandwidth. Theoretical peak to sidelobe level is achievable with time-bandwidth product value grater than 100. For time-bandwidth product smaller then 100 (i.e. short pulse duration or narrow deviation of FM modulation) peak-to-sidelobe level (PSL) and pulse compression coefficient are significantly reduced. Non-linear frequency modulated (NLFM) radar signal for small time-bandwidth product features better PSL and pulse compression coefficient. The NLFM signal synthesis algorithm and simulation results are presented in the paper. LFM and NLFM signals with small time-bandwidth product are compared and results are discussed in aspect of radar resolution improvement. © 2012 IEEE.

Sankowski M.,Przemyslowy Institute of Telecommunications
IET Radar, Sonar and Navigation | Year: 2011

A problem of tracking tactical ballistic missiles (TBMs) in a long-range air-surveillance radar is considered. An effective tracking algorithm is presented, which is based on continuous-time dynamic models of object motions and on a discrete-time model of measurement process. The estimator utilises an innovative combination of kinematic models of TBM movements in radar 'range-azimuth-elevation' coordinates, continuous-discrete extended Kalman filtering, interacting multiple-model state estimation and probabilistic data association. The performance and robustness of the new algorithm was proved by extensively testing using real and simulated radar data. For the purpose of this study its properties are illustrated using simulations. © The Institution of Engineering and Technology 2011.

Czyronis P.M.,Przemyslowy Institute of Telecommunications
Circuits, Systems, and Signal Processing | Year: 2014

Dynamic programming problem for discrete-time fractional order systems with quadratic performance index has been formulated and solved. A new method for numerical computation of optimal dynamic programming problem has been presented. The efficiency of the method has been demonstrated on numerical example and illustrated by graphs. Graphs also show the differences between the fractional and classical (standard) systems theory. Results for other cases of the coefficient alpha α, and not illustrated with numerical examples, have been obtained through a computer algorithm written for this purpose. © 2014 Springer Science+Business Media New York.

Sankowski M.,Przemyslowy Institute of Telecommunications
International Journal of Electronics and Telecommunications | Year: 2011

The basic problem of tracking manoeuvring moving objects (e.g. aircrafts, ships) lies in unpredictability of object manoeuvres, with respect to the time of occurrence, duration and the type of trajectory. In this paper most representative methods of modelling and state estimation techniques applied to Manoeuvring Target Tracking (MTT) are briefly reviewed. Classification of existing approaches is made in the context of realistic and instrumentalistic paradigms of the philosophy of science. A practical example is also given that shows the impact of selecting models and estimation methods on the performance of the tracking filter for Air Traffic Control (ATC) radar.

Zych M.,Przemyslowy Institute of Telecommunications
International Journal of Electronics and Telecommunications | Year: 2011

The paper describes the simulation and measurement results for a ground penetrating SAR radar. The main purpose of this paper is to present the complexity of the issues relating to GPR. Permittivity of the ground determination error causes the resolution deterioration of the resulting image therefore an important task of the digital signal processing is the correct estimation of the permittivity. The article presents several methods devoted to this subject. As a simulation model of SAR system the pulse radar with LFM (Linear Frequency Modulation) signal has been applied. The aim of the experiment is to test ability of the SAR system to obtain fully focused image of the underground targets. The real data measurements took place on the 6th floor at the Faculty of Electronics and Information - Warsaw University of Technology. During measurement campaign the GPR SAR demonstrator mounted on the rails wagon has been used to generate radar motion.

Samczynski P.,Przemyslowy Institute of Telecommunications | Samczynski P.,Warsaw University of Technology | Kulpa K.S.,Warsaw University of Technology
IEEE Transactions on Geoscience and Remote Sensing | Year: 2010

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. © 2009 IEEE.

Gasztold M.,Przemyslowy Institute of Telecommunications
2014 20th International Conference on Microwaves, Radar and Wireless Communications, MIKON 2014 | Year: 2014

This article presents the design and measurement results of a three element antenna array that uses two high division ratio Wilkinson power dividers. This solution provides a beam that is tilted from the ground while maintaining side lobes level below -20dB. The current distribution for such an antenna pattern has very steep amplitude differences that are hardly realizable in the conventional microstrip technology. Because of that, power dividers were designed using Wilkinson topology with the defected ground structure (DGS). DGS provides an additional inductance component that increases the microstrip line's characteristic impedance value. It allows to maintain the width of the line wide enough to be fabricated with enough tolerance. © 2014 Warsaw University of Technology (WUT).

Meller M.,Przemyslowy Institute of Telecommunications | Tujaka S.,Przemyslowy Institute of Telecommunications
IEEE Transactions on Aerospace and Electronic Systems | Year: 2012

The problem of signal reception in a noise radar is considered. It is assumed that heavy clutter reflections are present. In such conditions, correlation processing suffers from the problem of noise floor in the ambiguity function of random signals. It is proposed to replace correlation processing with least squares (LS) based methods. In particular, a highly efficient block least mean squares (block LMS) algorithm is studied in detail. It is demonstrated that, compared with the correlation processing, block LMS shows significant advantages in terms of robustness to clutter. Simulation experiments confirm that when heavy clutter is present, the proposed method outperforms correlation processing significantly. © 2006 IEEE.

The invention relates to a method and an apparatus finding application in radar systems, in particular those generating and processing broadband radar pulses of constant amplitude with linear and nonlinear frequency modulation. A complex radar pulse consists of a number of subpulses of different carrier frequencies and in case of insufficient frequency separation the subpulses reciprocal intermodulation occurs limiting detection range and causing false detections. Method consists in determining the low-pass representation (4) of a plurality N of radar subpulse signals wherein each radar subpulse signal is processed simultaneously; and then in time-multiplexing (5); limiting (6) amplitude fluctuations; shifting (8) frequency spectrum into original carrier frequencies and band-pass filtering (9) of the complex radar pulse modified according to preceding steps. Determining the low-pass representations of a plurality N of radar subpulse signals further comprises steps of sharing radar subpulse signals processing channel into a plurality N of processing channels, mixing the subpulse signal with a heterodyne generator signal and eliminating undesired results of signal mixing and reducing frequency spectrum of subpulses. The step of shifting the frequency spectrum comprises steps of selecting an adequate carrier frequency waveform, reading from mass data storage means the selected carrier frequency waveform and mixing the carrier waveform signal with low-pass representation of a radar subpulse signal. The step of time-multiplexing, limiting amplitude fluctuations and shifting the frequency spectrum are performed sequentially under a supervision of control means, and repeated so many times as the number of subpulses.

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