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Search results for: AMPEROMETRIC GAS SENSORS
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Acoustic radar employing particle velocity sensors
PublicationA concept, practical realization and applications of a passive acoustic radar to automatic localization, tracking of sound sources were presented in the paper. The device consist of the new kind of multichannel miniature sound intensity sensors and a group of digital signal processing algorithms. Contrary to active radars, it does not emit the scanning beam but after receiving surroundings sounds it provide information about the...
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System of wireless magnetic sensors for detection and identification of ferromagnetic vehicles
PublicationThe paper presents the results of deformation of the Earth's magnetic field by land vehicles. Basing on the analysis of the shape of the magnetic field deformation, it is possible to detect and identify a vehicle. In order to eliminate the interference of the Earth's magnetic field by the environment, the measurements were performed in a differential configuration. Under a development project a wireless system of magnetic sensors...
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Evaluation of Three Peptide Immobilization Techniques on a QCM Surface Related to Acetaldehyde Responses in the Gas Phase
PublicationThe quartz-crystal microbalance is a sensitive and universal tool for measuring concentrations of various gases in the air. Biochemical functionalization of the QCM electrode allows a label-free detection of specific molecular interactions with high sensitivity and specificity. In addition, it enables a real-time determination of its kinetic rates and affinity constants. This makes QCM a versatile bioanalytical screening tool for...
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Determination of Odor Intensity of Binary Gas Mixtures Using Perceptual Models and an Electronic Nose Combined with Fuzzy Logic
PublicationMeasurement and monitoring of air quality in terms of odor nuisance is an important problem. From a practical point of view, it would be most valuable to directly link the odor intensity with the results of analytical air monitoring. Such a solution is offered by electronic noses, which thanks to the possibility of holistic analysis of the gas sample, allow estimation of the odor intensity of the gas mixture. The biggest problem...
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Microwave Alignment and Displacement Sensors in Groove Gap Waveguide Technology
PublicationThis paper is aimed at presenting highly sensitive microwave displacement and alignment sensors. With this goal, the method of realizing mechanically tunable cavity resonators in groove gap waveguides technology is presented. The resonance frequency of the cavity is then used for displacement sensing. It is also demonstrated that the symmetry properties of a pair of groove gap waveguide cavities can be used to improve the robustness...
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TASTE QUALITIES ESTIMATION BY TASTE SENSE AND ELECTROCHEMICAL SENSORS
PublicationThe principles of taste sense and kinds of tastes (sweet, salty, sour, bitter, umami and fat) have been described. Food quality estimation by taste sense: organoleptic testing and sensory analysis has been presented. The principle of operation of potentiom etric sensor composed of several Ion Selective Electrodes or All Solid State Electrodes with polymeric membranes and macromolecular chemical compounds sensitive to substances...
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FFT analysis of temperature modulated semiconductor gas sensor response for the prediction of ammonia concentration under humidity interference
PublicationThe increasing environmental contamination forces the need to design reliable devices for detecting of the volatile compounds present in the air. For this purpose semiconductor gas sensors, which have been widely used for years, are often utilized. Although they have many advantages such as low price and quite long life time, they still lack of long term stability and selectivity. Namely, environmental conditions have significant...
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Modeling of multi-cavity Fabry-Perot optical fiber sensors
PublicationReflectance characteristics of a two-cavity extrinsic Fabry-Perot optical fiber sensor were investigated using computer modeling. Calculations were performed using a plane wave-based approach, selected for clarity of results. Based on the modeling results, it can be concluded that the two-cavity Fabry-Perot interferometer can be used to measure two different quantities, such as refractive index and temperature, independently. It...
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The computational methods in the development of a novel multianalyte calibration technique for potentiometric integrated sensors systems
PublicationIn recent years, integration and miniaturization of ion-selective electrodes (ISEs) have brought many benefits resulting in the possibility of simultaneous determination of the ions concentration in small volume samples. One of the key problems related to the preparation of potentiometric integrated sensors systems (PISSs) is a calibration procedure due to the necessity to calibrate each particular sensor separately. The main aim...
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Time-domain measurement methods for R, L and C sensors based on aversatile direct sensor-to-microcontroller interface circuit
PublicationtIn the paper new time-domain measurement methods for determining values of resistive (R), inductive(L) and capacitive (C) sensors based on a versatile direct sensor-to-microcontroller interface for microcon-trollers with internal analog-to-digital converters (ADCs) and analog comparators (ACs) are presented.The interface circuit consists of a reference resistor Rrworking as a voltage divider, a given R, L or C sensorand a microcontroller...
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Perforating systems in shale gas recovery
PublicationHydraulic fracturing is common method of shale gas recovery. Due to environmental, economical and technological problems many alternative technologies have been developed. One of the most promising group of technologies is based on perforating systems. This paper describes theoretical and practical aspects of best known technologies used to create perforations. New perforating/fracturing technologies which can replace hydraulic fracturing...
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Fixed Pattern Noise Reduction and Linearity Improvement in Time-Mode CMOS Image Sensors
PublicationIn the paper, a digital clock stopping technique for gain and offset correction in time-mode analog-to-digital converters (ADCs) has been proposed. The technique is dedicated to imagers with massively parallel image acquisition working in the time mode where compensation of dark signal non-uniformity (DSNU) as well as photo-response non-uniformity (PRNU) is critical. Fixed pattern noise (FPN) reduction has been experimentally validated...
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Integration of inertial sensors and GPS system data for underwater navigation
PublicationThe Inertial Navigation System (INS) is usually employed to determine the position of an underwater vehicles, like Remotely Operated Vehicles (ROV) and, more recently, Autonomous Underwater Vehicle (AUV). The accuracy of the position provided by the INS, which uses accelerometers and gyroscopes, deteriorates with time. An external aiding sources such as the Global Positioning System (GPS) can be employed to reduce the error growth...
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Fluctuation-enhanced and conductometric gas sensing with nanocrystalline NiO thin films: A comparison
PublicationNanocrystalline thin films of NiO were prepared by advanced reactive gas deposition, and their responses to formaldehyde, ethanol and methane gases were studied via fluctuation-enhanced and conductometric methods Thin films with thicknesses in the 200–1700-nm range were investigated in as-deposited form and after annealing at 400 and 500 °C. Morphological and structural analyses showed porous deposits with NiO nanocrystals having...
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QUASI-DISTRIBUTED NETWORK OF LOW-COHERENCE FIBER-OPTIC FABRY-PÉROT SENSORS WITH CAVITY LENGTH-BASED ADDRESSING
PublicationDistributed measurement often relies on sensor networks. In this paper, we present the construction of low coherent fiber-optic Fabry-Pérot sensors connected into a quasi-distributed network. We discuss the mechanism of spectrum modulation in this type of sensor and the constraints of assembly of such sensors in the network. Particular attention was paid to separate the signals from individual sensors, which can be achieved by...
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Measurement method for capacitive sensors for microcontrollers based on a phase shifter
PublicationA complete measurement method dedicated to capacitive sensors has been developed. It includes the development of hardware (an analogue interface circuit for microcontrollers with built-in times/counters and analogue comparators) and software (a measurement procedure and a systematic error calibration (correction) algorithm which is based on a calibration dictionary). The interface circuit consists of a low-pass filter and a phase...
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Exhaust gas temperature measurements in diagnostic examination of naval gas turbine engines. Part I: Steady-state processes
PublicationThe article presents a possible method of detecting failures in the flow section and supply system of a naval gas turbine engine based on the exhaust gas temperature measured behind the gas generator. This temperature is a basic diagnostic parameter use for evaluating the technical state of the turbine engine in operation, and is monitored during engine start-ups, accelerations and decelerations of rotor units, and steady-load...
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Data fusion of GPS sensors using Particle Kalman Filter for ship dynamic positioning system
PublicationDepending on standards and class, dynamically positioned ships make use of different numbers of redundant sensors to determine current ship position. The paper presents a multi-sensor data fusion algorithm for the dynamic positioning system which allows it to record the proper signal from a number of sensors (GPS receivers). In the research, the Particle Kalman Filter with data fusion was used to estimate the position of the vessel....
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Pulsed UV-irradiated Graphene Sensors for Ethanol Detection at Room Temperature
PublicationA graphene-based gas sensor fabricated in a FET (GFET) configuration and its sensitivity towards ethanol and methane is reported. Detection of ethanol at the level of 100 ppm was observed under pulsed UV irradiation and after cleaning by UV light in the N2 ambient. Reduction of the frequency of UV irradiation pulses resulted in increased changes in sensor resistance in the presence of ethanol. Improved sensing behavior was ascribed...
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APPLICABILITY OF INLET AIR FOGGING TO MARINE GAS TURBINE
PublicationThe dependency of marine gas turbine on the ambient temperature leads to a decrease of the gas turbine power output in arid areas. Very often gas turbine power output demand is high and the power margins originally designed into the driver , has been exhausted. In such circumstances the inlet air fogging is an effective compensation of gas turbine power. In this paper an analysis of inlet air fogging applicability to marine gas...
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Application of Multiplicative Drift Correction and Component Correction methods on simulated gas sensor array responses
PublicationSensor response drift is one of the most challenging problems in gas-analyzing systems. Such systems, commonly called electronic noses, are expected to be reliable and reproducible in the long term. Due to the drift phenomena, electronic noses usability is limited to the relatively short period of time, and frequent recalibrations of device are required. Because it is very hard to fabricate sensors without drift, this phenomenon...
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Dopants and gas modifiers in ion mobility spectrometry
PublicationThe ion mobility techniques, including the most commonly used drift-tube ion mobility spectrometry (IMS) and differential mobility spectrometry (DMS), are used successfully for the detection of a wide range of organic compounds in the gas phase. In order to improve detection quality, admixtures are added to gas streams flowing through the detector. Dopants mostly prevent the ionization of interfering chemicals however, better detection...
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Design Analysis of Micro Gas Turbines in Closed Cycles
PublicationThe problems faced by designers of micro-turbines are connected with a very small volume flow rate of working media which leads to small blades’ height and high rotor speed. In the case of gas turbines this limitation can be overcome by the application of a closed cycle with very low pressure at the compressor inlet (lower than atmospheric pressure). In this way we may apply a micro gas turbine unit of accepted efficiency to work...
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An optimised placement of the hard quality sensors for a robust monitoring of the chlorine concentration in drinking water distribution systems
PublicationThe problem of an optimised placement of the hard quality sensors in drinking water distribution systemsunder several water demand scenarios for a robust monitoring of the chlorine concentration is formulatedin this paper. The optimality is understood as achieving a desired trade off between the sensors and theirmaintenance costs and the accuracy of estimation of the chlorine concentration. The contribution of thiswork is a comprehensive...
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Sulfur compounds: Gas chromatography
PublicationSulfur compounds, due to their properties, are responsible for the damage of our environment. For this reason sulfur containing compounds are of constant concern in many fields. Gas chromatography (GC), due to combination of separation capability and sensitive detection is a prime technique for the analysis of thes compounds in various matrices. The chapter rewies general problems of the determination of these compounds by GC and...
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Study of ZrS3-based field-effect transistors toward the understanding of the mechanisms of light-enhanced gas sensing by transition metal trichalcogenides
PublicationExtending knowledge of the properties of low-dimensional van der Waals materials, including their reactivity to the ambiance, is important for developing innovative electronic and optoelectronic devices. Transition metal trichalcogenides with tunable optical band gaps and anisotropic conductivity are an emerging class among low- dimensional structures with the possibility of gate tunability and photoreactivity. These properties...
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New developments in preparation and use of standard gas mixtures
PublicationStandard gas mixtures are commonly applied in all stages of analytical work related to the analysis of gaseous samples. Numerous techniques for generating standard gas mixtures are in use. In this article, we present new developments regarding the production of standard gas mixtures, with particular focus on improvements in the application of dynamic techniques for generating them. Furthermore, we describe the application of new...
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Multicore Optical Fibres For Sensors
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A measurement method for capacitive sensors based on a versatile direct sensor-to-microcontroller interface circuit
PublicationIn the paper, there is presented a new time-domain measurement method for determining the capacitance values of capacitive sensors, dedicated, among others, to capacitive relative humidity sensors. The method is based on a versatile direct sensor-to-microcontroller interface for microcontrollers with internal analog comparators (ACs) and with precision voltage reference sources, e.g. digital-to-analog converters (DACs). The reference...
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Exhaust gas temperature measurements in diagnostic examination of naval gas turbine engines. Part III. Diagnostic and operating tolerances
PublicationThe third part of the article presents a method for detecting failures of the automatic engine control system with the aid of an exhaust gas temperature setter, specially designed and machined for this purpose. It also presents a procedure of identifying the operating tolerances and determining the diagnostic tolerances for the exhaust gas temperature recorded in the naval turbine engine during the start-up and acceleration processes....
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Exhaust gas temperature measurements in diagnostic examination of naval gas turbine engines. Part II. Unsteady processes
PublicationThe second part of the article presents the results of operating diagnostic tests of a two- and three-shaft engine with a separate power turbine during the start-up and acceleration of the rotor units. Attention was paid to key importance of the correctness of operation of the automatic engine load control system, the input for which, among other signals, is the rate of increase of the exhaust gas flow temperature. The article...
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A comparative study of pentanol (C5 alcohol) and kerosene blends in terms of gas turbine engine performance and exhaust gas emission
PublicationThe growing demand for sustainable and clean energy sources provides the incentive for the development of alternative fuels. Simultaneously, the development of gas turbine technologies with flexible fuel supply systems enables the use of alternative non-fossil fuels that can play key roles in contributing to global efforts in meeting emissions targets. This paper presents the current state of knowledge on the production and potential...
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Combined chemoresistive and in situ FTIR spectroscopy study of nanoporous NiO films for light-activated nitrogen dioxide and acetone gas sensing
PublicationThe chemoresistive sensor response of nanoporous NiO films prepared by advanced gas deposition was investigated by combined resistivity and in situ FTIR spectroscopy, with and without simultaneous light illumination, to detect NO2 and acetone gases. The sensitivity towards NO2 increased dramatically under UV irradiation employing 275 nm light. Improved sensitivity was observed at an elevated temperature of 150 °C. In situ FTIR...
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An Ultra-Low-Energy Analog Comparator for A/D Converters in CMOS Image Sensors
PublicationThis paper proposes a new solution of an ultra-low-energy analog comparator, dedicated to slope analog-to-digital converters (ADC), particularly suited for CMOS image sensors (CISs) featuring a large number of ADCs. For massively parallel imaging arrays, this number may be as high as tens-hundreds of thousands ADCs. As each ADC includes an analog comparator, the number of these comparators in CIS is always high. Detailed analysis...
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Novel Desorber for Online Drilling Mud Gas Logging
PublicationThis work presents the construction solution and experimental results of a novel desorber for online drilling mud gas logging. The traditional desorbers use mechanical mixing of the liquid to stimulate transfer of hydrocarbons to the gaseous phase that is further analyzed. The presented approach is based on transfer of hydrocarbons from the liquid to the gas bubbles flowing through it and further gas analysis. The desorber was...
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Determination of cyanide ion in urine samples using ion chromatography with pulsed amperometric detection.
PublicationCyanides are widely applied in industrial activity, including gold and silver mining and the production of organic chemicals. HCN is also formed directly from fossil fuel combustion sources from gasoline and diesel vehicles. In natural environment, in plants seeds for example an apple seed, it exists as a cyanogenic glycosides. The amount of cyanide ions originating from food products is however rather small. Larger concentrations...
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Interface circuit for impedance sensors using two specialized single-chip microsystems
PublicationW artykule przedstawiono obwód interfejsu przeznaczony do pomiaru parametrów impedancyjnych czujników lub celek pomiarowych instalowanych na obiektach technicznych. Umożliwia on pomiar modułu i argumentu impedancji w zakresie 10ohm
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Fiber-optic Fabry-Pérot sensors – modeling versus measurements results
PublicationThis paper describes how parameters of investigated substances and the fiber-optic Fabry-Pérot sensing interferometer affect the spectrum of the optical radiation at the output of the sensor. First, the modeling of the operation of the sensing interferometer was conducted. Most important parameters and effects that were taken into account are: dependences of the refractive indices of the core and the cladding, as well the mode...
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Application of a Gas Sensor Array to Effectiveness Monitoring of Air Contaminated with Toluene Vapors Absorption Process
PublicationThis article demonstrates the application of a gas sensor array to monitor the effectiveness of the absorption process of air stream purification from odorous compounds (toluene vapors). A self-constructed matrix consisting of five commercially available gas sensors was used. Multiple linear regression (MLR) was selected as the statistical technique used to calibrate the matrice. Gas chromatography coupled with a flame ionization...
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Possibilities of Increasing the Overall Efficiency of Gas-steam CHP Microplant
PublicationThe paper presents ways to increase the efficiency of a gas-steam micro power plant by modifying the cycle combination. The modification consists in partial release of the fluid downstream of the gas turbine and using it for ORC fluid overheating and evaporation. Advantages of this solution over the simplest gas and steam cycles’ combination are demonstrated.
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Carbon dioxide sequestration during shale gas recovery
PublicationThis paper presents literature on theoretical and practical aspects of gas production from shale using carbon dioxide fracturing. Development of technical and environmental aspects of carbon dioxide fracturing technologies is also considered. Patents applicable to carbon dioxide fracturing are reviewed. There were also conducted researches to evaluate possibility of carbon dioxide sequestration in shale gas reservoirs.
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Security Assessment of a Turbo-Gas Power Plant
PublicationCritical infrastructures are exposed to new threats due to the large number of vulnerabilities and architectural weaknesses introduced by the extensive use of information and communication technologies. This paper presents the results of an exhaustive security assessment for a turbo-gas power plant.
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Shooting Gas Cylinders to Prevent Their Explosion in Fire
PublicationGas cylinders in general, and particularly cylinders containing acetylene, constitute a great potential danger to fire and rescue services involved in salvage operations. Experiments show that gas cylinders with acetylene, oxygen, hydrogen, CNG, LPG or CO2 may blow after short exposition to heat with very destructive effect as fragments of blown cylinder may fly even several hundred meters. In the case of acetylene the explosion...
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Design of novel highly sensitive sensors for crack detection in metal surfaces: theoretical foundation and experimental validation
PublicationThe application of different types of microwave resonators for sensing cracks in metallic structures has been subject of many studies. While most studies have been focused on improving the sensitivity of planar crack sensors, the theoretical foundation of the topic has not been treated in much detail. The major objective of this study is to perform an exhaustive study of the principles and theoretical foundations for crack sensing...
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Gas turbines – technological development and potential use in CAES systems
PublicationThis article briefly describes Compressed Air Energy Storage (CAES), focusing on the technological development of one of the key elements of such systems – the gas turbines. It presents the basic parameters and features of gas turbines, as well as turbine classes with example models. Main tendencies in the structural and technological development are discussed. Changes and trends on electric energy markets are becoming more and...
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Perspectives of Fluctuation-Enhanced Gas Sensing by Two-Dimensional Materials
PublicationWe present the results of gas sensing using the fluctuation-enhanced sensing method in selected two-dimensional materials (2DMs). We claim that gas sensing selectivity can be improved further by considering semiconducting two-dimensional materials doped by noble metal nanoparticles. The 2DMs' structures exhibit some imperfections defined by their structure, occurring repeatedly there. These imperfections are adsorption-desorption...
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Two-dimensional gas chromatography – principles and application in fruits analysis
PublicationTwo-dimensional gas chromatography is a rapidly developing analytical technique. One of the major uses of this technique is its use for food analysis. The paper presents the principle of operation and history of this analytical technique. The specification of the two-dimensional gas chromatography technique has been discussed. The principles of separation of ingredients and application of the method, particularly in the analysis...
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Inorganic membrane: a game changer for gas separation and purification
PublicationThis review explores the advancements and remaining challenges in inorganic membrane science, particularly focusing on their potential for industrial applications. It delves into the fundamental principles of inorganic membrane design, fabrication, and characterization techniques. The review also critically analyzes key challenges faced by inorganic membranes, such as physical aging, plasticization, defective formation, and fouling....
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Integration of inertial sensors and GPS system data for the personal navigation in urban area
PublicationGPS and Inertial Navigation Systems (INS) have complementary properties and they are therefore well suited for integration. The integrated solution offers better long-term accuracy than a stand-alone INS and better integrity, availability and continuity or a stand-alone GPS receiver, making it suitable for demanding applications. The complementary features of INS and GPS are the main reasons why integrated GPS/INS systems are becoming...
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Automatic sound source localization in disturbing conditions using acoustic vector sensors
PublicationA concept, practical realization and applications of a passive acoustic radar to automatic localization and tracking of sound sources in disturbing conditions were presented in the paper. The device consists of the new kind of multichannel miniature sound intensity sensors and a group of digital signal processing algorithms. The sensitivity of the realized acoustic radar was examined in free sound field. Several kinds of sound...