Two detection algorithms (heuristic and CFAR) for target detection in pulsar FSR are analyzed usi... more Two detection algorithms (heuristic and CFAR) for target detection in pulsar FSR are analyzed using the simulation approach. The simulation results are verified by processing of the experimental data obtained by the radio observatory Dwingeloo in the Netherlands. The simulation and experimental results proved that the CFAR detection algorithm is more effective than the heuristic algorithm and can be successfully used in a pulsar FSR system for protection of air space from unwanted air objects.
Abstract : Previously a technique was described for obtaining a multi-purpose motor oil additive ... more Abstract : Previously a technique was described for obtaining a multi-purpose motor oil additive which has good detergent-dispersive properties owing to the interaction of phosphorus pentasulphide with olefinic hydrocarbon polymers C3-C5, followed by treatment of the reaction's product with alcanolamine C2-C12. But this additive still lacks sufficient antioxydant qualities at high temperatures. The method proposed in the report makes it possible to obtain an additive with both high temperature antioxidant and detergent-dispersive (cleaning) properties. It differs in that a known additive is treated at 140-280C with a boron compound such as boracic acid or its polymers. (Author)
This paper focuses on scientific issues related to new application of GPS in radar networks that ... more This paper focuses on scientific issues related to new application of GPS in radar networks that use the effect of Forward Scattering (FS) of electromagnetic waves to detect and estimate targets on their GPS radio shadows. The aim of the paper is to describe the experimental study of GPS radio shadows of different objects irradiated by GPS signals and to develop a possible algorithm for signal processing of the radio shadows of objects. Registration of FS-GPS radio shadows from moving targets is performed using a small commercial GPS antenna and the 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 including size, speed and direction of movement, distance to the receiver. The information extracted from FS-GPS radio shadows of objects can be used in different application...
The paper considers the concept of a Global Position System (GPS) shadow Forward-Scatter Radar (F... more The paper considers the concept of a Global Position System (GPS) shadow Forward-Scatter Radar (FSR) for detection of air targets at short distances. This paper discusses the experimental results obtained after processing the GPS signals received near the airport in Sofia, Bulgaria. This research aims to demonstrate the ability to automatically detect low-flying aircrafts by a Forward Scattering GPS system. The other goal of this article is to study and estimate different types of GPS shadows created by aircrafts of different sizes and shapes.
2018 22nd International Microwave and Radar Conference (MIKON), 2018
An approach and algorithm are proposed for separating the useful signal from a moving cosmic targ... more An approach and algorithm are proposed for separating the useful signal from a moving cosmic target and the direct signal transmitted by GPS satellites, on the background of the receiver noise. The algorithms for separating the useful signal will be based on the principle of separation in speed of two GPS signal sequences, the first — with a satellite velocity (reference signal), the second — with the target velocity. We will evaluate their performance with computer calculation or simulation.
2017 18th International Radar Symposium (IRS), 2017
The goal of this paper is to introduce a new concept - using Data Mining approach for radar class... more The goal of this paper is to introduce a new concept - using Data Mining approach for radar classification of vehicles, based on their GPS shadow signals detected in a GPS L1-based Forward Scatter Radar (FSR) system. Real data is used for the current experiments, recording the GPS radio shadows of several moving vehicles with commercial non-professional GPS equipment. The records are further processed in MATLAB computational environment in order to obtain the estimated parameters of the GPS shadows. Data Mining approach is then implemented for classifying the cars, comparing classifiers generated with different classification algorithms - a decision tree, a neural network, and a Bayesian classifier, for two different variants of the class variable, taking three or two possible values. The best results are achieved for the two values of the class variable and the best performing classifiers are the neural networks.
2017 18th International Radar Symposium (IRS), 2017
This paper focuses on application of pulsar signals for pulsar-based navigation. The aim of the s... more This paper focuses on application of pulsar signals for pulsar-based navigation. The aim of the study is to present a possible algorithm for signal processing of pulsar signals, which consists of epoch folding, filtering and detection, and evaluate it using the real experimental data obtained from the radio observatory Dwingeloo, the Netherlands.
In this paper a Hough detector is compared with a Cell Averaging Constant False Alarm Rate (CA CF... more In this paper a Hough detector is compared with a Cell Averaging Constant False Alarm Rate (CA CFAR) detector in the presence of pulse jamming. The detection probability and the average detection threshold of these two types of CFAR detectors are studied. The experimental results are obtained by numerical analysis in MATLAB computational environment. The analytical results obtained for the Hough detector can be used in both radar and communication receiver networks.
2020 21st International Symposium on Electrical Apparatus & Technologies (SIELA), 2020
Forest fires are natural disasters defined as uncontrolled and unrestrained movements of fire acr... more Forest fires are natural disasters defined as uncontrolled and unrestrained movements of fire across forested areas. They pose a permanent hazard of forest and forested land loss. The increasingly more frequent forest fires are often of great magnitudes, threatening not only forests but also crops, residential areas, and human lives. Forest fire fighting involves three crucial stages: prevention, detection, and extinguishment. This paper discusses the preventive measures against forest fires as well as methods of forest monitoring as a means of preserving forest biodiversity. Using modern information technology, such as geographic information systems (GIS), can improve strategic and tactical planning and actions aimed at fire prevention. The paper showcases the application of selected information system as forest fire protection in Serbia.
The mountain hiking destinations become more popular as this is one of the possible ways to cope ... more The mountain hiking destinations become more popular as this is one of the possible ways to cope with workplace stress and to prevent burnout. In contrast to the tourist destinations, mountain hiking requires special attention due to the variety of mountain trails satisfying the same starting and finishing point for a particular route. For the goal, a two-stage search-based approach for a determining of possible routes considering the users’ preferences is developed. The first stage is focused on the determining of possible hiking routes taking into account the requirements and tourists’ preferences, while the second stage concerns the sorting of already determined hiking routes. The applicability of the described approach is illustrated and the obtained results demonstrate the capability in searching and sorting of mountain hiking trails using directed weighted multigraph including tourists’ preferences.
2020 21st International Radar Symposium (IRS), 2020
The article analyses the possibility for survemance airplanes by using solar radio emission in a ... more The article analyses the possibility for survemance airplanes by using solar radio emission in a forward scatter radar system. It’s estimated as the magnitude of SNR at the input of the signal detector calculated depending on the size of airplanes, the way of the airplanes moving relative to the baseline (perpendicularly or parallel) for various values of the solar radio emission. The time of the contact of airplanes with the receiver beam influences on the duration of the signal received from airplanes. Changes in the angular width of the FS zone and in values of the aircraft FS RCS depending on the frequency values of the solar radio emission are also taken account in the calculation of SNR.
Proceedings of the 9th International Conference on Telecommunications and Remote Sensing, 2020
The phenomenon of diffraction occurs when a wave encounters an obstacle in its path, as a result ... more The phenomenon of diffraction occurs when a wave encounters an obstacle in its path, as a result of which it changes its rectilinear propagation in space. Wave diffraction is described in the literature as: Fresnel diffraction (when the target is close to the receiver) and Fraunhofer diffraction (when the target is far from the receiver). A diffraction model from opaque objects in a near and far observation zone is presented and investigated. The diffraction pattern was interpreted using a Fourier transform. The relationships between the object parameters, the distance from the object to the receiver and the wavelength of the signal are studied. The obtained diffraction model can be used to study the phenomenon of direct signal propagation in bistatic radar systems as well as to detect and evaluate the parameters of moving objects.
The paper analyses the possibility of Forward Scatter Radar (FSR) systems to detect airplanes usi... more The paper analyses the possibility of Forward Scatter Radar (FSR) systems to detect airplanes using cosmic emission from pulsars and planets (pulsar, Sun, Moon). A suboptimal multichannel algorithm for joint detection and evaluation of the parameters of the forward scattering signal created by an airplane (duration and velocity) is proposed, with preliminary compensation of the powerful direct signal emitted by cosmic sources (pulsar, Sun and Moon). The expressions for calculation of the Signal-to-Noise Ratio (SNR) at the input of the detector and the compensator are obtained. The detection characteristics are also obtained, and the requirements for the suppression coefficient of the compensator are evaluated. A methodology for calculating the maximum distance for detecting an aircraft using a described algorithm is proposed. The obtained results show that due to the Forward Scatter (FS) effect, there is the theoretical possibility to detect airplanes at close ranges by FSRs, which ...
In the last decade, cloud computing has become an extremely important business assistant that off... more In the last decade, cloud computing has become an extremely important business assistant that offers significantly lower costs than traditional computer-aided resource provision and greater adaptability to business changes. Thus, it helps them to achieve their business goals. The development of cloud computing poses significant risks, which serve as a partial barrier to their use by the businesses. Security and protection of information are considered to be one of the most critical points in the use of cloud computing. Compared to traditional solutions, cloud computing moves application software and databases to large data centers where information and service management are not always secure and reliable. As a result of this, the community and businesses have many concerns and questions about the security of data and applications in cloud infrastructures. In addition, concerns about data security and applications also arise due to the fact that both user data and applications are m...
In this chapter, the original advanced algorithms for stepped-frequency GPR imaging are considere... more In this chapter, the original advanced algorithms for stepped-frequency GPR imaging are considered. In stepped-frequency GPR, the range profile formation is carried out by reconstruction of a wideband chirp by combining a set of stepped-frequency chirp signals in the time domain. Using the Modelsim simulator, it is shown that the processor VIRTEX II Pro is suitable for implementation of this algorithm. A simple convolution algorithm for simulation of stepped-frequency GPR images from multi-layered subsurface media is described. Different approaches and algorithms for the basic GPR signal and image processing are also considered in this chapter. These algorithms are used for improving the image quality of underground objects, e.g. pipes. It is shown that applying different filters (CFAR, Hough, Kalman,Particle) to GPR image processing is a good decision in the sense of estimation accuracy, probability of target detection and false alarm. 1 Faculty of Mathematics and Informatics, Sofi...
Two detection algorithms (heuristic and CFAR) for target detection in pulsar FSR are analyzed usi... more Two detection algorithms (heuristic and CFAR) for target detection in pulsar FSR are analyzed using the simulation approach. The simulation results are verified by processing of the experimental data obtained by the radio observatory Dwingeloo in the Netherlands. The simulation and experimental results proved that the CFAR detection algorithm is more effective than the heuristic algorithm and can be successfully used in a pulsar FSR system for protection of air space from unwanted air objects.
Abstract : Previously a technique was described for obtaining a multi-purpose motor oil additive ... more Abstract : Previously a technique was described for obtaining a multi-purpose motor oil additive which has good detergent-dispersive properties owing to the interaction of phosphorus pentasulphide with olefinic hydrocarbon polymers C3-C5, followed by treatment of the reaction's product with alcanolamine C2-C12. But this additive still lacks sufficient antioxydant qualities at high temperatures. The method proposed in the report makes it possible to obtain an additive with both high temperature antioxidant and detergent-dispersive (cleaning) properties. It differs in that a known additive is treated at 140-280C with a boron compound such as boracic acid or its polymers. (Author)
This paper focuses on scientific issues related to new application of GPS in radar networks that ... more This paper focuses on scientific issues related to new application of GPS in radar networks that use the effect of Forward Scattering (FS) of electromagnetic waves to detect and estimate targets on their GPS radio shadows. The aim of the paper is to describe the experimental study of GPS radio shadows of different objects irradiated by GPS signals and to develop a possible algorithm for signal processing of the radio shadows of objects. Registration of FS-GPS radio shadows from moving targets is performed using a small commercial GPS antenna and the 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 including size, speed and direction of movement, distance to the receiver. The information extracted from FS-GPS radio shadows of objects can be used in different application...
The paper considers the concept of a Global Position System (GPS) shadow Forward-Scatter Radar (F... more The paper considers the concept of a Global Position System (GPS) shadow Forward-Scatter Radar (FSR) for detection of air targets at short distances. This paper discusses the experimental results obtained after processing the GPS signals received near the airport in Sofia, Bulgaria. This research aims to demonstrate the ability to automatically detect low-flying aircrafts by a Forward Scattering GPS system. The other goal of this article is to study and estimate different types of GPS shadows created by aircrafts of different sizes and shapes.
2018 22nd International Microwave and Radar Conference (MIKON), 2018
An approach and algorithm are proposed for separating the useful signal from a moving cosmic targ... more An approach and algorithm are proposed for separating the useful signal from a moving cosmic target and the direct signal transmitted by GPS satellites, on the background of the receiver noise. The algorithms for separating the useful signal will be based on the principle of separation in speed of two GPS signal sequences, the first — with a satellite velocity (reference signal), the second — with the target velocity. We will evaluate their performance with computer calculation or simulation.
2017 18th International Radar Symposium (IRS), 2017
The goal of this paper is to introduce a new concept - using Data Mining approach for radar class... more The goal of this paper is to introduce a new concept - using Data Mining approach for radar classification of vehicles, based on their GPS shadow signals detected in a GPS L1-based Forward Scatter Radar (FSR) system. Real data is used for the current experiments, recording the GPS radio shadows of several moving vehicles with commercial non-professional GPS equipment. The records are further processed in MATLAB computational environment in order to obtain the estimated parameters of the GPS shadows. Data Mining approach is then implemented for classifying the cars, comparing classifiers generated with different classification algorithms - a decision tree, a neural network, and a Bayesian classifier, for two different variants of the class variable, taking three or two possible values. The best results are achieved for the two values of the class variable and the best performing classifiers are the neural networks.
2017 18th International Radar Symposium (IRS), 2017
This paper focuses on application of pulsar signals for pulsar-based navigation. The aim of the s... more This paper focuses on application of pulsar signals for pulsar-based navigation. The aim of the study is to present a possible algorithm for signal processing of pulsar signals, which consists of epoch folding, filtering and detection, and evaluate it using the real experimental data obtained from the radio observatory Dwingeloo, the Netherlands.
In this paper a Hough detector is compared with a Cell Averaging Constant False Alarm Rate (CA CF... more In this paper a Hough detector is compared with a Cell Averaging Constant False Alarm Rate (CA CFAR) detector in the presence of pulse jamming. The detection probability and the average detection threshold of these two types of CFAR detectors are studied. The experimental results are obtained by numerical analysis in MATLAB computational environment. The analytical results obtained for the Hough detector can be used in both radar and communication receiver networks.
2020 21st International Symposium on Electrical Apparatus & Technologies (SIELA), 2020
Forest fires are natural disasters defined as uncontrolled and unrestrained movements of fire acr... more Forest fires are natural disasters defined as uncontrolled and unrestrained movements of fire across forested areas. They pose a permanent hazard of forest and forested land loss. The increasingly more frequent forest fires are often of great magnitudes, threatening not only forests but also crops, residential areas, and human lives. Forest fire fighting involves three crucial stages: prevention, detection, and extinguishment. This paper discusses the preventive measures against forest fires as well as methods of forest monitoring as a means of preserving forest biodiversity. Using modern information technology, such as geographic information systems (GIS), can improve strategic and tactical planning and actions aimed at fire prevention. The paper showcases the application of selected information system as forest fire protection in Serbia.
The mountain hiking destinations become more popular as this is one of the possible ways to cope ... more The mountain hiking destinations become more popular as this is one of the possible ways to cope with workplace stress and to prevent burnout. In contrast to the tourist destinations, mountain hiking requires special attention due to the variety of mountain trails satisfying the same starting and finishing point for a particular route. For the goal, a two-stage search-based approach for a determining of possible routes considering the users’ preferences is developed. The first stage is focused on the determining of possible hiking routes taking into account the requirements and tourists’ preferences, while the second stage concerns the sorting of already determined hiking routes. The applicability of the described approach is illustrated and the obtained results demonstrate the capability in searching and sorting of mountain hiking trails using directed weighted multigraph including tourists’ preferences.
2020 21st International Radar Symposium (IRS), 2020
The article analyses the possibility for survemance airplanes by using solar radio emission in a ... more The article analyses the possibility for survemance airplanes by using solar radio emission in a forward scatter radar system. It’s estimated as the magnitude of SNR at the input of the signal detector calculated depending on the size of airplanes, the way of the airplanes moving relative to the baseline (perpendicularly or parallel) for various values of the solar radio emission. The time of the contact of airplanes with the receiver beam influences on the duration of the signal received from airplanes. Changes in the angular width of the FS zone and in values of the aircraft FS RCS depending on the frequency values of the solar radio emission are also taken account in the calculation of SNR.
Proceedings of the 9th International Conference on Telecommunications and Remote Sensing, 2020
The phenomenon of diffraction occurs when a wave encounters an obstacle in its path, as a result ... more The phenomenon of diffraction occurs when a wave encounters an obstacle in its path, as a result of which it changes its rectilinear propagation in space. Wave diffraction is described in the literature as: Fresnel diffraction (when the target is close to the receiver) and Fraunhofer diffraction (when the target is far from the receiver). A diffraction model from opaque objects in a near and far observation zone is presented and investigated. The diffraction pattern was interpreted using a Fourier transform. The relationships between the object parameters, the distance from the object to the receiver and the wavelength of the signal are studied. The obtained diffraction model can be used to study the phenomenon of direct signal propagation in bistatic radar systems as well as to detect and evaluate the parameters of moving objects.
The paper analyses the possibility of Forward Scatter Radar (FSR) systems to detect airplanes usi... more The paper analyses the possibility of Forward Scatter Radar (FSR) systems to detect airplanes using cosmic emission from pulsars and planets (pulsar, Sun, Moon). A suboptimal multichannel algorithm for joint detection and evaluation of the parameters of the forward scattering signal created by an airplane (duration and velocity) is proposed, with preliminary compensation of the powerful direct signal emitted by cosmic sources (pulsar, Sun and Moon). The expressions for calculation of the Signal-to-Noise Ratio (SNR) at the input of the detector and the compensator are obtained. The detection characteristics are also obtained, and the requirements for the suppression coefficient of the compensator are evaluated. A methodology for calculating the maximum distance for detecting an aircraft using a described algorithm is proposed. The obtained results show that due to the Forward Scatter (FS) effect, there is the theoretical possibility to detect airplanes at close ranges by FSRs, which ...
In the last decade, cloud computing has become an extremely important business assistant that off... more In the last decade, cloud computing has become an extremely important business assistant that offers significantly lower costs than traditional computer-aided resource provision and greater adaptability to business changes. Thus, it helps them to achieve their business goals. The development of cloud computing poses significant risks, which serve as a partial barrier to their use by the businesses. Security and protection of information are considered to be one of the most critical points in the use of cloud computing. Compared to traditional solutions, cloud computing moves application software and databases to large data centers where information and service management are not always secure and reliable. As a result of this, the community and businesses have many concerns and questions about the security of data and applications in cloud infrastructures. In addition, concerns about data security and applications also arise due to the fact that both user data and applications are m...
In this chapter, the original advanced algorithms for stepped-frequency GPR imaging are considere... more In this chapter, the original advanced algorithms for stepped-frequency GPR imaging are considered. In stepped-frequency GPR, the range profile formation is carried out by reconstruction of a wideband chirp by combining a set of stepped-frequency chirp signals in the time domain. Using the Modelsim simulator, it is shown that the processor VIRTEX II Pro is suitable for implementation of this algorithm. A simple convolution algorithm for simulation of stepped-frequency GPR images from multi-layered subsurface media is described. Different approaches and algorithms for the basic GPR signal and image processing are also considered in this chapter. These algorithms are used for improving the image quality of underground objects, e.g. pipes. It is shown that applying different filters (CFAR, Hough, Kalman,Particle) to GPR image processing is a good decision in the sense of estimation accuracy, probability of target detection and false alarm. 1 Faculty of Mathematics and Informatics, Sofi...
In the radars, the performance of signal detectors is seriously degraded by arrival of impulse no... more In the radars, the performance of signal detectors is seriously degraded by arrival of impulse noise that extremely worsens their detectability characteristics. There are many papers, in which different Constant False Alarm Rate (CFAR) detectors have been analysed in the presence of randomly arriving impulse interference described as Bernoulli pulse sequences. In this book, the randomly arriving impulse interference is mathematically described as Binominal pulse sequences. This model of impulse noise is used for numerical analysis of two types of CFAR pulse detectors (CACFAR and EXC CFAR) and two types of CFAR pulse train detectors with binary (CFAR BI) and non-coherent (CFAR PI) integration. The detectability is expressed in terms of the detection probabilities and the Average Decision Threshold (ADT). The analytical expressions for calculating both quality characteristics, obtained in this book, provide a basis for comparison analysis of CFAR detectors in the presence of Binomial (or Bernoulli-Poisson) impulse noise. The detectability of typical pulse and pulse train detectors is numerical analysed in the presence of Poisson and Binomial impulse noise. Therefore, the proposed detectors can be used in different radar systems and secondary applications of communication technologies.
In this book, several advanced detection algorithms for Track-Before-Detect (TBD) procedures usin... more In this book, several advanced detection algorithms for Track-Before-Detect (TBD) procedures using the Polar Hough Transform (HT) are proposed and studied. In real radar applications, however, when the two target parameters, range and azimuth, vary in time, the PHT can be successfully used because in that case the input parameters of the PHT are two polar coordinates of a target – range and azimuth. Such advanced structures of the TBD using the PHT have been developed and studied in the book. The PHT is analogous to the standard HT and performs all the data collected for several previous scans into a single large multidimensional polar data map. The general structure of an adaptive Polar Hough detector with binary integration is similar to that of a standard Hough detector. The Polar Hough transform maps all points from the (range-azimuth) space into the Hough space of patterns. The association with a particular pattern is done by thresholding the Hough parameter space with a predetermined threshold. In order to enhance the target detectability in conditions of Randomly Arriving Impulse Interference (RAII), a CFAR processor is proposed to be used for signal detection.
In this book, it is assumed that the noise amplitude is a Rayleigh distributed random variable and therefore the noise power is an exponentially distributed variable. Different Hough detectors that employ CFAR processors such as Cell Averaging (CA), Excision (EXC), Binary Integration (BI), Excision with Binary Integration (EXC BI) for signal detection in the (r-a) space are studied and compared in the book. The structure of these Hough detectors includes the following operations - CFAR signal detection in the area of observation and the PHT of the target range measurements from the observation area into the Hough parameter space, binary integration of data in the parameter space and, finally, linear trajectory estimation. The results obtained show that different CFAR processors work successfully in combination with a Hough detector in conditions of RAII, and allow to evaluate the parameters of the targets. The detection probability of a Polar Hough detector is calculated by Brunner’s method as for a standard Hough detector. The use of the PHT instead of the standard HT allows detecting target trajectories in real situations when targets move at variable speeds along arbitrary linear trajectories.
The TBD approach that applies the HT to multi-sensor detection in conditions of intensive RAII is proposed in the book. As usual, the fusion center of a decentralized system applies binary integration of the data received from each sensor. In such a system, at the first stage, radars produce local decisions by the TBD-PHT processing and at the second stage - all the local decisions are transferred from radars into the fusion node where coordinates and time are associated in the Global Observation Space (GOS). The centralized system, however, firstly associates data with common coordinates and time received from sensors and then performs them by the TBD-PHT processing. In this context, two variants of a centralized asynchronous net with association of signals or signal detections are developed and analyzed. The algorithm with association of signals includes two stages. At the first stage, the signals received from sensors are non-coherently accumulated in the signal matrixes of the fusion centre, because the size of signal matrixes and their cells are the same for the entire radar net. At the second stage the accumulated signals are transferred into the GOS. The algorithm with association of signal detections firstly accumulates decisions for signal detection after CFAR processing in each sensor, secondly - transfers detections in the GOS. The expressions for calculating the probability characteristics, i.e. the probability of target detection, trajectory estimation and the false alarm probability, are derived under the assumption that both target coordinates (range and azimuth) and both parameters of the Hough parameter space ρ and θ are measured with or without errors. The results obtained show that the detection probability of multi-sensor centralized TBD-PHT processors is higher than that of the decentralized detectors. The performance evaluation of multi-sensor TBD-PHT processors has been carried out by Monte-Carlo simulations in MATLAB computing environment. The DPA based Hough detector is close to the potential of the most effective multi-sensor CSA Hough detector. The target coordinate measurement errors in the (r-t) space mitigate the operational efficiency of multi-sensor Hough detectors. The needed operational efficiency requires the appropriate sampling of the Hough parameter space.
The book includes the following chapters: 1. Straight Lines and trajectories Detection Using Hough Transform; 2. Trajectories Detection Using Polar Hough Transform; 3. Probability characteristics of CFAR Hough detectors in the presence of randomly arriving impulse interferences; 4. Multi-sensor (multi-channel) data association using polar Hough transform.
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Papers by Ivan Garvanov
In this book, it is assumed that the noise amplitude is a Rayleigh distributed random variable and therefore the noise power is an exponentially distributed variable. Different Hough detectors that employ CFAR processors such as Cell Averaging (CA), Excision (EXC), Binary Integration (BI), Excision with Binary Integration (EXC BI) for signal detection in the (r-a) space are studied and compared in the book. The structure of these Hough detectors includes the following operations - CFAR signal detection in the area of observation and the PHT of the target range measurements from the observation area into the Hough parameter space, binary integration of data in the parameter space and, finally, linear trajectory estimation. The results obtained show that different CFAR processors work successfully in combination with a Hough detector in conditions of RAII, and allow to evaluate the parameters of the targets. The detection probability of a Polar Hough detector is calculated by Brunner’s method as for a standard Hough detector. The use of the PHT instead of the standard HT allows detecting target trajectories in real situations when targets move at variable speeds along arbitrary linear trajectories.
The TBD approach that applies the HT to multi-sensor detection in conditions of intensive RAII is proposed in the book. As usual, the fusion center of a decentralized system applies binary integration of the data received from each sensor. In such a system, at the first stage, radars produce local decisions by the TBD-PHT processing and at the second stage - all the local decisions are transferred from radars into the fusion node where coordinates and time are associated in the Global Observation Space (GOS). The centralized system, however, firstly associates data with common coordinates and time received from sensors and then performs them by the TBD-PHT processing. In this context, two variants of a centralized asynchronous net with association of signals or signal detections are developed and analyzed. The algorithm with association of signals includes two stages. At the first stage, the signals received from sensors are non-coherently accumulated in the signal matrixes of the fusion centre, because the size of signal matrixes and their cells are the same for the entire radar net. At the second stage the accumulated signals are transferred into the GOS. The algorithm with association of signal detections firstly accumulates decisions for signal detection after CFAR processing in each sensor, secondly - transfers detections in the GOS. The expressions for calculating the probability characteristics, i.e. the probability of target detection, trajectory estimation and the false alarm probability, are derived under the assumption that both target coordinates (range and azimuth) and both parameters of the Hough parameter space ρ and θ are measured with or without errors. The results obtained show that the detection probability of multi-sensor centralized TBD-PHT processors is higher than that of the decentralized detectors. The performance evaluation of multi-sensor TBD-PHT processors has been carried out by Monte-Carlo simulations in MATLAB computing environment. The DPA based Hough detector is close to the potential of the most effective multi-sensor CSA Hough detector. The target coordinate measurement errors in the (r-t) space mitigate the operational efficiency of multi-sensor Hough detectors. The needed operational efficiency requires the appropriate sampling of the Hough parameter space.
The book includes the following chapters: 1. Straight Lines and trajectories Detection Using Hough Transform; 2. Trajectories Detection Using Polar Hough Transform; 3. Probability characteristics of CFAR Hough detectors in the presence of randomly arriving impulse interferences; 4. Multi-sensor (multi-channel) data association using polar Hough transform.