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Dive into the research topics where Anna Dzvonkovskaya is active.

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Featured researches published by Anna Dzvonkovskaya.


ieee international radar conference | 2008

Low power High Frequency Surface Wave Radar application for ship detection and tracking

Anna Dzvonkovskaya; Klaus-Werner Gurgel; Hermann Rohling; Thomas Schlick

High-frequency (HF) radars are operated in the 3-30 MHz frequency band and are known to cover ranges up to some thousand kilometers. Sky wave over-the-horizon radars (OTHR) utilize reflection by the ionosphere, but they require a transmit power up to 100 kilowatts. Especially for oceanographic applications, low power high frequency surface wave radar (HFSWR) systems have been developed, which use ground wave propagation along the salty ocean surface. The WERA HF radar system transmits a power as low as 30 watts, but achieves detection ranges up to 200 kilometers, which are far beyond the conventional microwave radar coverage. Due to external noise, radio frequency interference, and different kinds of clutter, special techniques for target detection have to be applied. This paper describes a new signal processing approach based on a curvilinear regression analysis for thresholding combined with a constant false-alarm-rate (CFAR) algorithm for detection. The target locations detected by the HF radar are passed to a tracking filter utilizing range, azimuth, as well as radial and azimuthal velocities to track the ship locations. For a 12-hour period real HF radar data from the WERA system were processed and secondary ship locations were recorded from the automatic identification system (AIS). This data set is used to assess the performance of the HF radar detections. Comparisons have been made for a maximum distance of 5 km between AIS and radar detected locations. The deviation between AIS and radar detected locations was below 1 kilometer in 77% of these comparisons. A number of ships was detected and tracked by the radar, but could not be used for comparisons due to the lack of AIS information.


ieee radar conference | 2010

HF radar performance analysis based on AIS ship information

Anna Dzvonkovskaya; Hermann Rohling

High-Frequency (HF) radars are operated in the 3–30 MHz frequency band. For oceanographic applications low transmit power HF radar systems have been developed, which use surface electromagnetic wave propagation along the salty ocean surface. The WERA HF radar system transmits a power of 30 watts but achieves detection ranges up to 200 km, which are far beyond the conventional microwave radar coverage. Hence the radar system can be used for coastal monitoring. Due to external noise, radio frequency interference, and sea clutter the radar detection capability is limited. Real measured radar data from the WERA system were recorded for a 12-hour period. The measured radar data were correlated with simultaneously available Automatic Identification System (AIS) information, which shows current ship position, speed, course and type. This paper presents statistical analysis of maximum detectable range and target reflectivity to estimate the radar performance in case of different cargo ship sizes. Based on the order-statistic constant false alarm rate (OS-CFAR) detection rule the potentially detectable target range and aspect angle of different ship categories were analyzed.


international radar symposium | 2006

CFAR Target Detection Based on Gumbel Distribution for HF Radar

Anna Dzvonkovskaya; Hermann Rohling

High frequency (HF) radars are capable to detect and track targets at extremely long ranges. But the signal environment that includes external noise, different kinds of clutter and interference will significantly limit the detection and system capability. This paper considers a new approach to solve the target detection problem in a complex HF radar signal environment. It uses conventional constant false-alarm-rate (CFAR) detection procedure but based in this case on an untypical assumption of Gumbel distributed power spectrum values along range cells for thresholding. The CFAR detection test rule was combined with a local peak determination procedure. The proposed detection scheme was tested using real HF radar data and gave very promising results.


international geoscience and remote sensing symposium | 2012

OCean surface current measurements using HF radar during the 2011 Japan tsunami hitting Chilean coast

Anna Dzvonkovskaya

One of the oceanographic high-frequency (HF) radar systems is located in Chile. The radar was in operation when the 2011 Japan tsunami waves hit the Chilean coast after propagating throughout the Pacific Ocean. The unique chance to observe a natural tsunami event using an HF radar showed that such radars are capable to measure tsunami surface current velocity. Large deviations in ocean current measurements were observed by the radar system. The tsunami wave train was clearly seen in radar measurements and it was compared with water level measurements by the tide gauge. The tsunami wave periodicity was estimated for both types of measurement data. It showed agreement estimating two different tsunami wave periods.


ieee international radar conference | 2006

Target Detection with Adaptive Power Regression Thresholding for HF Radar

Anna Dzvonkovskaya; Hermann Rohling

High frequency (HF) radars are capable to detect and track targets at extremely long ranges. But the signal environment that includes external noise, different kinds of clutter and interference will significantly limit the detection performance and system capability. This paper considers a new approach to solve the target detection problem in a complex HF radar signal environment. It uses a conventional constant false-alarm-rate (CFAR) detection procedure but the thresholding scheme is based on regression analysis of power spectrum values along range and Doppler cells. The CFAR detection test rule was combined with a local peak determination procedure. The proposed detection scheme has been tested using real HF radar data and gave very promising results


europe oceans | 2009

Simulation of tsunami signatures in ocean surface current maps measured by HF radar

Anna Dzvonkovskaya; Klaus-Werner Gurgel; Thomas Pohlmann; Thomas Schlick; Jiangling Xu

The high frequency (HF) surface wave radar has a unique capability to monitor the coastal environment far beyond the conventional microwave radar coverage. The HF radar could contribute to the development and improvement of Tsunami Early Warning Systems. Bragg-resonant backscattering by ocean waves with half the electromagnetic radar wavelength allows measuring the ocean surface current at distances up to 200 km. The developed software package allows reconstructing an ocean surface current map of the area observed by HF radar based on the radar range-Doppler spectrum processing. In case of an approaching tsunami, a strong ocean surface current signature can be observed by the radar when the tsunami wave enters the shelf edge. In order to simulate the signals seen by an HF radar in case of a tsunami travelling towards the coast, the tsunami induced current velocity is calculated using the oceanographic HAMburg Shelf Ocean Model (HAMSOM) model, then converted into modulating signals, and superposed to the measured radar backscatter signals. After applying conventional signal processing techniques, the radar spectra include the simulated tsunami wave. The surface current map based on these spectra has a pattern, which changes very quickly in the shelf area before the tsunami wave reaches the beach. Specific radial tsunami current signatures are clearly observed in these maps. If the shelf edge is far off the coast sufficiently then the first appearance of such signatures can be monitored by an HF radar system early enough to issue a warning message about an approaching tsunami.


international radar symposium | 2016

Multi-radar multi-target tracking algorithm for maritime surveillance at OTH distances

Dejan Nikolió; Zdravko Popovic; Milos Borenovió; Nikola Stojkovió; Vladimir D. Orlic; Anna Dzvonkovskaya; Branislav M. Todorovic

The aim of this paper is to propose, develop and test multi-radar multi-target tracking algorithm for maritime surveillance at over-the-horizon (OTH) distances. The proposed algorithm utilizes a weighted pure minimum mean square error (MMSE) algorithm for multi-radar data fusion and adaptive alpha - beta tracking algorithm for target tracking. The developed data fusion algorithm calculates the weighted center of mass of all targets observed by OTH radars (OTHRs) within a gate radius of predicted position, and uses it for a track update process. During the process a weighting factor which will be used in an adaptive alpha-beta tracking algorithm is derived. The weighting factor as well as alpha and beta factors are updated in each observation period and depend on all targets, which have fallen into a gate radius during the track update process. The algorithm is designed, implemented, and tested in an environment consisting of a simulated network of two OTHRs with significantly overlapping surveillance areas.


international radar symposium | 2014

Initial results of ship detection and tracking using WERA HF ocean radar with MIMO configuration

Anna Dzvonkovskaya; Thomas Helzel; Leif Petersen; Clifford R. Merz; Yonggang Liu; Robert H. Weisberg

High-Frequency (HF) radars are operated in the 3-30 MHz frequency band. For oceanographic applications low transmit power HF radar systems have been developed, which use surface electromagnetic wave propagation along the salty ocean surface. This paper presents a new approach to use Multiple Input Multiple Output (MIMO) technique for compact HF ocean radar deployments and positive economic benefits without reducing overall system performance. The initial results show that such MIMO HF radar configuration can be used for both oceanographic measurements and ship tracking applications. Ship detection and tracking are tested using real WERA HF radar measurements for a MIMO configuration with collocated receive antennas. The comparison between standard and MIMO mode results is focused on azimuthal angle estimation.


oceans conference | 2014

Initial surface current measurements on the West Florida shelf using WERA HF ocean radar with multiple input multiple output (MIMO) synthetic aperture

Anna Dzvonkovskaya; Clifford R. Merz; Yonggang Liu; Robert H. Weisberg; Thomas Helzel; Leif Petersen

High-frequency (HF) radar systems located at the coast are well-known as a measurement tool for synoptic online mapping of ocean surface current fields. These radars use surface electromagnetic wave propagation coupled to the salty ocean surface and are capable of monitoring thousands of square kilometers of the ocean surface. For oceanographic applications, low transmit power HF radar beamforming systems have been developed for operation in the 3-30 MHz frequency band. These systems require the use of a linear array of receive antenna elements whose inter-element spacing is dependent upon the operational frequency chosen. This paper presents a new approach of applying the Multiple Input Multiple Output (MIMO) technique with a synthesized antenna aperture to a compact HF ocean radar. The initial results show that the MIMO HF radar configuration with collocated receive antennas can be used for both oceanographic measurements and ship tracking applications. Initial MIMO results also reveal that positive results can be achieved from a reduced length receive array without reducing overall system performance. The comparison between standard and MIMO configurations has been focused on the estimation of surface current velocities and comparison with in-situ acoustic Doppler current profiler (ADCP) measurements.


international radar symposium | 2008

Long binary phase codes with good autocorrelation properties

Anna Dzvonkovskaya; Hermann Rohling

In 1953 R.H. Barker introduced the well-known binary phase codes with good autocorrelation properties. The magnitude of all sidelobes in the related autocorrelation function (ACF) is not larger than one in this case. But the longest known Barker Code has the length N=13, which is a real limitation in practical applications. Binary codes with much longer code length N are required in many radar applications even if the sidelobes are much larger than one. This paper describes a design technique for very long binary phase codes (for any code length N ges 100) and shows the resulting performance figures in the related ACE For the code length of N = 4096 a peak sidelobe of -35.6 dB can be achieved applying the proposed design technique.

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Hermann Rohling

Hamburg University of Technology

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Mal Heron

James Cook University

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Eric W. Gill

Memorial University of Newfoundland

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Clifford R. Merz

University of South Florida

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Robert H. Weisberg

University of South Florida St. Petersburg

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