Chr. Kabakchiev

Study of moving target shadows using passive Forward Scatter radar systems

Forward Scatter GPS (FS-GPS) radio shadows formed by different moving objects are investigated in this article. FS radio shadow is essential physical phenomenon, which can be used to extract some useful information about the objects that generate it. Registration of FS-GPS radio shadows from moving targets is performed using a small commercial GPS antenna and stationary receiver. Topology of the experiment meets the requirements for the appearance of the FS effect. The results presented in this article show that from FS-GPS radio shadows of different objects can be extracted information about the parameters of the object (size, speed and direction of movement, distance to the receiver). The information obtained can be used in various applications like those in classic radar, including radio barriers, security, classification and identification of moving and stationary objects.

Data association algorithm in multiradar system

In this paper we apply a data association in track-before detect (TBD) with a polar Hough transform (PHT) in a radar network. The proposed algorithm is applied in multiple input multiple output (MIMO) radar system. We study the sensitivity of TBD multi-radar system as a function of the errors of target trajectory parameters measurement. The results are obtained in the presence of Randomly Arriving Impulse Interference (RAII) and the target coordinates (range and azimuth) are measurable with and without errors. The study of the signal processing used in detectors is performed through Monte-Carlo simulations in MATLAB computing environment.

Marine target classification and parameter estimation using Forward Scattering Radar

In this paper a possible original method for rough classification of marine target, through estimation of the velocity and linear size of moving sea objects using Forward Scattering Radar (FSR) system is present. The target velocity and size are estimated by cross-correlation between instantaneous frequencies of the input signal and the predefined reference signal. The estimation algorithm is tested on the base of real experimental signal from the boat moving with a given velocity, that have been obtained by the team from Birmingham University using Forward Scattering Radar.

Forward scatter radar detection and estimation of marine targets

In this paper we research original structure of the Bistatic Forward Scatter Radar detector and signal parameter estimator of the marine targets at the background of a sea clutter. The time duration, power, energy and the maximum of the Doppler frequency for MISL and other boat are estimate for many trails. These results will make possible to be used for the data mining classification with the WEKA software. We propose and original structure of the FSR Rough Target Classifier, of the marine targets at the background of a sea clutter. Using the CFAR processor approach for Target detection and parameter estimation of the first minimum and maximum frequency from Power Spectrum Density, we receive the signal parameters in the FSR in the real time. On base this signal parameters, we calculate target parameters velocity and length from two equations, for velocity of targets in bistatic systems and for length of FSR target propose by Cherniakov. These parameters, length and velocity, we may to use for rough targets classification, because they consists all information about the boat. The research algorithm is investigated on the base of real data records that have been obtained by the team from Birmingham University and Sofia University using Forward Scattering Radar.

Detection and estimation of pulsar signals for navigation

The paper focuses on scientific issues related to new application of pulsar signals for airplane-based navigation. A possible algorithm for processing of pulsar signals that consists of epoch-folding, matched filtering and detection is proposed and evaluated in this paper. The algorithm proposed is verified using the real experimental data obtained from the radio observatory Dwingeloo, the Netherland. The serious trouble in this study is that the total number of the input data within a repetition period is much more of the number of samples in a pulsar template taken from the EPN database. Therefore have been developed and evaluated two new algorithms for epoch-folding, which not only improve Signal-to-Noise Ratio of pulsar signals but as well reduce the number of samples of the output signals to the required number.

CFAR BI Detector for Mariner Targets in Time Domain for Bistatic Forward Scattering Radar

One original structure of the CFAR detector and parameter estimator of moving marine targets in conditions of natural interference using Bistatic Forward Scattering Radar (FSR) are presented in this paper. The specific one dimensional MTI CFAR processor with K/M-L batch processor and parameter estimator for a marine target with unknown size are investigated on the base of real data records that have been obtained by the team of the Birmingham University using Forward Scattering Radar.

Detection and classification of objects from their radio shadows of GPS signals

The paper focuses on scientific issues related to new application of GPS in radar networks using the effect of Forward Scattering (FS) of electromagnetic waves to detect, locate and classify objects by their GPS radio shadows. The aim of the paper is to make experimental studies of GPS radio shadows of different objects irradiated by GPS signals and to develop methods and algorithms for automatic detection, estimation and classification of the shadows of these objects. The practical utility of the results obtained is to use a specific processing of the received signal in the GPS receiver, then to use the extracted information for positioning and classification of moving objects; for accurate assessment of the geographic location of fixed objects by method triangulation in systems for transport management, security of zones, subsequent identification of the detected objects from digital geographical maps.

Signal processing of GPS radio shadows formed by moving targets

This paper focuses on scientific issues related to new application of GPS in the construction and development of radar networks using the effect of Forward Scatter (FS) of electromagnetic waves for detection of objects by using of their GPS radio shadows. The paper theme is new, it combines two thematic areas: processing of GPS signals and processing of radar signals in FS radar systems.

Analysis of multi-sensor radar detection based on the TBD-HT approach in ECM environment

This paper describes in details the performance of an advanced detecting algorithm for multi-sensor target Track Before Detection (TBD) through the Hough Transform (HT). The detection algorithm employs the idea of using the Hough Transform for joint detection of linear trajectory targets. The polar modification of the TBD-HT approach is applied to a multi-sensor Polar Hough detector for multi-sensor target/trajectory detection in ECM environment with a Stand-off-Jammer (SOJ). A CFAR detector is proposed for signal detection in the (r-t) space instead of fixed thresholding in order to enhance the target detectability in ECM environment. In this paper a centralized structure of a multi-sensor Polar Hough detector is considered. The expressions calculating the probability characteristics, i.e. the probability of target/trajectory detection and the false alarm probability, are analytically derived. The multi-channel TBD-HT detector probability characteristics are compared with those for the conventional signal processing.

The study of target shadows using passive FSR systems

The paper describes one possible algorithm for object detection by using of Forward Scatter (FS) radio shadows created by objects. The algorithm is verified on the experimental data collected by a GPS receiver with a small commercial antenna. The results obtained show the possibility for object detection when its FS shadow is present.