Pavel Bezousek

Radar technology in the Czech Republic

A contemporary status of radar technology in the Czech Republic is reviewed in this paper. We may find activity in many different directions in this field now. Those are: new primary radar development both for military and civil application, primary and secondary radar upgrades, new passive radar development for civil application, ELINT and ESM equipment, intruding alarm radar sensors for commercial application/high mass production, radar warning and seeking receivers and military targets RCS minimization.

Active antenna array concepts for precision approach radar

This paper describes an electronically scanned antenna array for a precision approach radar (PAR). Three antenna concepts are discussed and compared in terms of number of radiating and controlled elements, antenna gain and scanning time. Angular resolution for separated azimuth and elevation antennas with a monopuse method evaluation of the target angle in the case of two closely spaced targets is also discussed.

UWB through-wall propagation measurements

The propagation of ultra-wideband (UWB) signals is analyzed. The UWB radar output signals are formed both with transmitter and antenna. Moreover, they can be substantially affected due to electromagnetic wave propagation through walls. Experimental results and numerical simulations are analyzed and compared. The given examples show that the numerical simulations, which are very fast, could be reliable, when suitable wall parameters are used.

Model comparison of bistatic radar clutter

Bistatic radars are parts of coherent multistatic radar systems for air targets positioning and tracking in various systems including the Air Traffic Control. The signal processing in the bistatic radar invariably encounters with a competitive signal, reflected from terrain objects - the land clutter. In this paper a research in the area of bistatic radar clutter modeling is presented. After the bistatic clutter scenario is defined two land-clutter models, based on a common general geometry are described. The bistatic radar clutter power equation derived here ([9]) is used for computation of interesting parameters like a bistatic radar effective clutter cross section, a total clutter power and a clutter reflectivity. In the end the two models are compared with actually measured bistatic radar clutter with use of a real terrain profile around the radar.

Computing of bistatic cross-ambiguity function on GPU

The real-time computation of cross ambiguity function (CAF) using brute force and block processing methods is a challenging task for parallel programming techniques. CAF is a key function for successful location tracking by passive radar systems. In this paper, the comparison of CAF methods computation and using a Graphics Processing Unit (GPU) are presented. The main goal of the research is to compare the computation efficiency and speed of the CAF methods on the GPU hardware with a single or multi-Core PC workstation. The results show the highest speed-up factor using GPU for all CAF methods.

A TDOA system using received signal decomposition on delayed replicas

The paper deals with a received Wi-Fi (802.11 spec, b) signal, consisting of a dominant direct-path component and of a sum of multiple reflected signals. In this paper the system based on decomposition of RF data signals to a linear combination of delayed replicas is suggested. The dominant components TDOAs could then be evaluated with a higher accuracy. It is shown, that this method may significantly enhance position estimation accuracy in indoor TDOA systems.

Accuracy of spectral analysis methods for precision indoor positioning system

At the University of Pardubice there is currently developed a modern positioning system for localization of fire brigade and members of rescue corps. The TDOA based system use an OFDM wideband signal to separate direct propagated signal from mixture of its replicas created in a multipath channel. In the paper, the model of a received signal is presented and this signal is processed by spectrum analysis methods to estimate the direct propagated signal delay. The accuracy of nonparametric, parametric and subspace methods is compared and new insights into application of spectral analysis methods are presented.

Effects of signal distortion in a FMCW radar on range resolution

Frequency Modulated Continuous Wave (FMCW) radars are used in many range measurement applications. The effects of phase errors in radar antenna, circuit dispersion and of frequency modulation nonlinearity on FMCW radar resolution have been analyzed using computer simulation and experiments with a radar prototype in the 10 GHz band.

Secondary Surveillance Radar Antenna [Antenna Designer's Notebook]

This paper deals with a secondary surveillance radar (SSR) array antenna, which is intended for a system combining the secondary surveillance radar antenna and the primary surveillance radar antenna. It describes the patch array elements and the synthesis for the secondary surveillance radar array, considering both elevation and azimuth patterns for sum, difference, and sidelobe-suppression beams, and suspended stripline couplers. The utilization of multilayer techniques allows the connection of layers with patch radiating elements and layers with beamforming networks.

Multipath Propagation Effects of UWB Radars

The propagation of ultra wide band (UWB) signals is analyzed. The UWB radar output signals are formed both with transmitter and antenna. Moreover, they can be substantially affected due to electromagnetic wave propagation through walls and multipath effects. Multipath effects are analyzed and simulated numerically for various cases with several heights and distances.