Anna Kurowska

Bistatic ground-based passive SAR imaging using TerraSAR-X as an illuminator of opportunity

The paper presents an experiment with bistatic passive SAR imaging in a scenario involving the TerraSAR-X satellite as an illuminator of opportunity and a static, ground-based receiver. The experiment was performed during a measurement campaign carried out by the Warsaw University of Technology in July 2012. In the paper the design of an X-Band receiver system and the bistatic SAR processing used for imaging are described. Also the resultant images produced for different polarizations of transmitted waves are included.

The preliminary survey of ship recognition algorithms using ISAR images

This paper provides a preliminary survey of the algoritms used in ISAR imaging for the ship recognition. It provides an overview of existing literature and summarises the current state on a topic. The author of the paper focuses on the algorithms for a single target.

Power efficiency of high dynamic range noise waveform

Noise radars - radars that use random waveforms as sounding waveforms - are prone to what is known as a masking effect. This occurs when the correlation sidelobes of a strong target echo masks weaker echoes. In order to overcome this limitation, the sounding signals which have correlation functions with suppressed sidelobes may be used. When designing such signals, the power efficiency should be considered, which is increased by decreasing the peak to average power ratio of the waveform. In this paper filter-based waveform design methods are presented and discussed. Three different approaches are analyzed that modify filter-based sidelobe suppression algorithms in order to achieve good power efficiency of the output waveform. Both simulation and measurement results are shown presenting, the benefits of the proposed methods.

Supersonic target detection in passive radar

The detection of supersonic targets in passive radar is a challenge due to the high speed and acceleration of the targets. In the classical approach, where the crossambiguity function is used, the integration time is limited by the range and Doppler migration. In this paper the application of the extension of the crossambiguity function to the 3-dimensional range-Doppler-acceleration is presented. The target of interest was a supersonic target - a sounding rocket launched by the Student Astronautical Group of the Warsaw University of Technology. As an illumination signal the DVBT-signal was selected.

Wind farm interferences in Passive Coherent Location

Rapid growth in the number of wind farms may influence the performance of many radar systems. The radar echoes originating from wind turbines blades and tower may mask existing objects or generate false plots. In the presented paper the authors analyze the influence of a wind turbine on Passive Coherent Location radars and discuss the effectiveness of simple methods used to overcome problems associated with it. The results of a simulation along with the recorded echoes of the wind turbine gathered by DVB-T based passive radar demonstrator are also shown in the paper.

Spectrum shaping in zero correlation zone noise signals

Noise radars offers several advantages over classical ones, but they have to deal with the masking problem. The masking problem occurs when strong echoes mask weaker echoes in their correlation sidelobes. Moreover due to the increasing number of telecommunication and radar systems, the frequency band allocation becomes an issue and many systems may be forced to coexist in given frequency band. In this paper the novel technique of correlation sidelobe reduction and spectrum shaping of the pseudo-random signal is presented. The sidelobe suppression and band modeling is accomplished by sets of FIR filters. The theoretical analysis and simulations are presented.

Classification results of ISAR sea targets based on their two features

This paper focuses on a classification of ISAR low resolution imaging of sea targets (cargo vessels) using the most popular classifiers. First, a method of the raw, passive data collection is described. Second, two feature vectors related to a size of the object (its width and length) are extracted, which then are applied for separating the objects into classes. Finally, the accuracy analysis of different ISAR image classifiers is presented. It is shown that the algorithms (ex. decision tree, SVM) may effectively distinguish different types of the cargo vessels.