Examinando por Autor "Escot Bocanegra, D."

Mostrando 1 - 20 de 44

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Application of a Spherical Multi-Purpose Facility to the Selection of the Appropriate Radome for an On-Board POD Antenna
(Taylor and Francis Online, 2012-04-03) Poyatos Martínez, D.; Escot Bocanegra, D.; De Diego Custodio, E.; González Diego, I.; Sáez de Adana, F. M.; Montiel, I.; Instituto Nacional de Técnica Aeroespacial (INTA)
This paper presents the application of a new multi-purpose facility for electromagnetic tests to the measurement of the influence of radomes on the radiation of an antenna. The antenna under test is part of a project for mounting a small, low-cost, low-power electronic system in the pod of an unmanned aerial vehicle. The shape of the radome is restricted to the pod physical specifications, but several materials could be tested to assess its effect on the antenna, and to select the best fitted for this particular application.
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Application of Artificial Neural Networks to Complex Dielectric Constant Estimation from Free-Space Measurements
(Springer Link, 2009-03-16) Jurado Lucena, A.; Escot Bocanegra, D.; Poyatos Martínez, D.; Montiel, I.; Instituto Nacional de Técnica Aeroespacial (INTA)
Adequate characterization of materials allows the engineer to select the best option for each application. Apart from mechanical or environmental characterization, last decades’ rise in the exploitation of the electromagnetic spectrum has made increasingly important to understand and explain the behavior of materials also in that ambit. The electromagnetic properties of non-magnetic materials are governed by their intrinsic permittivity or dielectric constant and free-space measurements is one of the various methods employed to estimate this quantity at microwave frequencies. This paper proposes the application of Artificial Neural Networks (ANNs) to extract the dielectric constant of materials from the reflection coefficient obtained by free-space measurements. In this context, two kind of ANNs are examined: Multilayer Perceptron (MLP) and Radial Basis Function (RBF) networks. Simulated materials are utilized to train the networks with and without noise and performance is tested using an actual material sample measured by the authors in an anechoic chamber.
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Application of FDTD to HRRP Generation of a Cavity Model for NCTI Purposes
(Institute of Electrical and Electronics Engineers, 2011-07-04) Fernandez Recio, R.; Escot Bocanegra, D.; Poyatos Martínez, D.; Jurado Lucena, A.; Errasti Alcalá, B.; Montiel, I.; Instituto Nacional de Técnica Aeroespacial (INTA)
The application of a time-domain electromagnetic simulation code to a realistic and challenging problem like the high-resolution range profile (HRRP) generation of an inlet cavity model is presented in this paper. HRRPs can be used to accomplish noncooperative target identification (NCTI) of aircrafts by means of radar, and the database needed in this technique tends to be populated with predicted data obtained with software tools. Most codes employed with these purposes are frequency domain methods, which need multiple simulations at different adequately chosen frequencies, as well as some postprocessing, to get a radar signature. Instead, this paper focuses on finite difference time domain (FDTD) analysis of the response of a cavity, because of the relevance of these parts of an aircraft in the overall signature, and numerical results are compared with measurements performed by the authors in an anechoic chamber. This work also shows the advantages of using an electromagnetic code based on time domain for HRRP generation.
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Application of particle swarm optimization (PSO) to single-snapshot direction of arrival (DOA) estimation
(Institute of Electrical and Electronics Engineers, 2007-12-06) Escot Bocanegra, D.; Poyatos Martínez, D.; González, Iván; Sáez de Adana, F.; Cátedra, M. F.; Instituto Nacional de Técnica Aeroespacial (INTA)
This paper attempts to examine the feasibility of using an heuristic bio-inspired algorithm in DOA estimation. Specifically, particle swarm optimization (PSO) (Kennedy, et. al., 1995)
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Assessment of FEM simulations in EMC test setups for small aeronautical platforms
(Taylor and Francis Online, 2018-08-03) Plaza Gallardo, B.; Ramajo, O.; López, D.; Poyatos Martínez, D.; Escot Bocanegra, D.; Agencia Estatal de Investigación (AEI)
The rise of fly-by-wire systems together with the utilization of new composite materials make it more and more difficult to assess and guarantee aircraft electromagnetic compatibility (EMC). As a result, the design phase becomes of paramount importance in the aircraft production process. Performing actual EMC tests over different configurations in such a phase would be very costly and time consuming, so reliable computational techniques are being explored in the last years. However, proper validation is needed in order to gain confidence in the results obtained by simulations. In this regard, this paper presents the assessment of a simulation approach based on the finite element method to reproduce typical setups of an EMC test laboratory for small aeronautical platforms. The final test object is based on an unmanned aerial vehicle but, first, a simpler test case is used to tune and assess the simulation approach. Once the approach is both qualitatively and quantitatively validated with measurements, new setups involving the aeronautical specimen are analysed.
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BIANCHA: A spherical indoor facility for bistatic electromagnetic tests
(Institute of Electrical and Electronics Engineers, 2017-01-05) López Rodríguez, P.; Hernán Vega, O.; Poyatos Martínez, D.; Escot Bocanegra, D.; Ministerio de Economía y Competitividad (MINECO)
BIANCHA (BIstatic ANechoic CHAmber) is a singular facility located at the premises of the National Institute for Aerospace Technology (INTA), Spain. It was devised to enable both monostatic and bistatic automatic positioning and, therefore, permits to perform a wide variety of electromagnetic tests. In this regard, it is worth noting that in the last years, a renewed interest has arisen in bistatic radar. Some of the main reasons behind this renaissance are the recent advances in passive radar systems added to the advantages that bistatic radar can offer to detect stealth platforms. On the other hand, with the aim of developing new aeronautic materials with desired specifications, research on the electromagnetic properties of materials has also attracted much attention, demanding engineers and scientists to assess how these materials behave in the presence of electromagnetic fields. Consequently, this paper introduces BIANCHA and demonstrates its applicability for these purposes by presenting results of tests for two different applications: a bistatic scattering analysis of scaled aircraft targets and the extraction of the electromagnetic properties of composite materials utilized in an actual aeronautical platform.
Acceso Abierto
Caracterización de materiales aeronáuticos mediante la técnica Metal-Backed Free-Space medidos en la cámara polivalente BIANCHA
(Ministerio de Defensa: Secretaría Técnica, 2016-11-18) López Rodríguez, P.; Hernán Vega, O.; Poyatos Martínez, D.; Trallero Vela, R.; Escot Bocanegra, D.; Ministerio de Economía y Competitividad (MINECO)
El estudio de las propiedades electromagnéticas de materiales compuestos (o composites) ha atra´ıdo la atenci´on de los investigadores en las ´ultimas décadas. Ya que las propiedades de un material est´an estrechamente relacionadas con las de los elementos que lo componen, la idea es tratar de desarrollar materiales con un comportamiento determinado. Sin embargo, la predicción del comportamiento de un material a partir de sus constituyentes es un problema que aún no ha sido completamente resuelto y, por tanto, el interés en caracterizarlos sigue presente. En los últimos años se ha incrementado la utilización de materiales compuestos en diferentes estructuras aeronáuticas de tal manera que ciertas partes de una aeronave ya no son metálicas sino que están completamente fabricadas a partir de composites. Asimismo, con el avance de estos y el interés por fabricar aeronaves más ligeras y eficientes, se están diseñando incluso fuselajes completos de nueva generación con material compuesto; tal es el caso de algunos vehículos aéreos no tripulados (UAV) actuales. De ahí que su caracterización se haya convertido en una necesidad. En este sentido, esta comunicación tiene como objetivo la caracterización de una serie de materiales compuestos de fibra de vidrio utilizados en el fuselaje de un UAV real operado por el INTA, denominado SCRAB-II.
Acceso Abierto
Caracterización de materiales fabricados mediante tecnología FDM para aplicaciones de Radiofrecuencia
(Ministerio de Defensa: Secretaria General Técnica, 2018-10-22) Martín Iglesias, S.; Muñoz Rebate, I.; León Calero, M.; Fernández Romero, S.; Poyatos Martínez, D.; Plaza Gallardo, B.; Escot Bocanegra, D.; Agencia Estatal de Investigación (AEI)
La fabricación aditiva presenta numerosas ventajas, frente a técnicas tradicionales, para el desarrollo de diseños complejos y adaptados a la finalidad de la aplicación. La posibilidad de desarrollar estructuras multi-material e integrar componentes electrónicos supone un avance para el desarrollo de aplicaciones en el campo del electromagnetismo. Para beneficiarse de estas ventajas, es necesario investigar en profundidad el comportamiento de los diferentes materiales disponibles. En esta comunicación, se presenta el estudio experimental mediante el cual se ha analizado una gran variedad de materiales empleados en FDM (Fused Deposition Modeling). El objetivo de este estudio es conocer el comportamiento electromagnético de estos materiales. Las probetas fabricadas han sido analizadas mediante la técnica “Open-Ended Coaxial Probe (OECP)” proporcionando información sobre su permitividad eléctrica, a partir de la cual es posible obtener el coeficiente de transmisión. Los materiales con mejor comportamiento dieléctrico fueron sometidos a ensayos de transmisión en espacio libre en una cámara anecoica polivalente para medidas electromagnéticas, BIANCHA (BIstatic ANechoic CHamber), validando de este modo los resultados obtenidos con la sonda coaxial. Los ensayos realizados han proporcionado información relevante para el desarrollo de futuras aplicaciones en radiofrecuencia (RF).
Acceso Abierto
Class Identification of Aircrafts by Means of Artificial Neural Networks Trained with Simulated Radar Signatures.
(The EM Academy, 2011-05-27) Jurado Lucena, A.; Montiel, I.; Escot Bocanegra, D.; Poyatos Martínez, D.; Instituto Nacional de Técnica Aeroespacial (INTA)
Non-Cooperative Target Recognition (NCTR) of aircrafts from radar measurements is a formidable problem that has drawn the attention of engineers and scientists over the last years. NCTR techniques typically involve a database with a huge amount of information from different known targets and a reliable identification algorithm able to highlight the likeness between measured and stored data. This paper uses High Resolution Range Profiles produced with a high-frequency software tool to train Arti cial Neural Networks for distinguishing between different classes of aircrafts. Actual data from the ORFEO measurement campaign are used to assess the performance of the trained networks.
Acceso Abierto
Comparing Open Area Test Site and Resonant Chamber for Unmanned Aerial Vehicle's High-Intensity Radiated Field Testing
(Institute of Electrical and Electronics Engineers, 2018-01-18) Fernández Romero, S.; López Rodríguez, P.; Escot Bocanegra, D.; Poyatos Martínez, D.; Añón Cancela, M.; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI)
Open area test sites (OATS) have been traditionally employed for aircraft electromagnetic compatibility certification tests because of the large size of these items. In this regard, unmanned aerial vehicles (UAVs) have emerged in the last years and, albeit being sometimes notably smaller, yet they have to accomplish for the same certification process. This paper investigates into the possibility of using a reverberation chamber for performing two aircraft low-level coupling tests, namely, low-level direct drive and low-level swept fields, and compares the results with those obtained in an OATS, in both cases using a representative part of a UAV.
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Comparison of Facilities for Low Level Coupling Tests in UAV EMC Certification
(Institute of Electrical and Electronics Engineers, 2017-11-30) Fernández Romero, S.; Escot Bocanegra, D.; Poyatos Martínez, D.; Añón Cancela, M.; López Rodríguez, P.; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI)
The rise in the utilization of Unmanned Aerial Vehicles (UAVs) in the last years has also brought concerns in terms of Electromagnetic Compatibility (EMC) regulation of these platforms. Depending on the nature and operations of the UAVs, they are being required to go through the same processes than an aircraft EMC certification of aircraft involves a wide variety of tests. This paper deals with two aircraft low level coupling tests, namely, Low Level Direct Drive (LLDD) and Low Level Swept Fields (LLSF) and compares the results obtained in two different sites. On one hand, an Open Area Test Site (OATS) will be employed and, on the other hand, a Reverberation Chamber (RC) will be the other facility examined. The object under test will be a representative part of an UAV.
Acceso Abierto
Comparison of Metal-Backed Free-Space and Open-Ended Coaxial Probe Techniques for the Dielectric Characterization of Aeronautical Composites
(Multidisciplinary Digital Publishing Institute (MDPI), 2016-06-24) López Rodríguez, P.; Escot Bocanegra, D.; Poyatos Martínez, D.; Weinmann, F.; Instituto Nacional de Técnica Aeroespacial (INTA); Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI)
The trend in the last few decades is that current unmanned aerial vehicles are completely made of composite materials rather than metallic, such as carbon-fiber or fiberglass composites. From the electromagnetic point of view, this fact forces engineers and scientists to assess how these materials may affect their radar response or their electronics in terms of electromagnetic compatibility. In order to evaluate this, electromagnetic characterization of different composite materials has become a need. Several techniques exist to perform this characterization, all of them based on the utilization of different sensors for measuring different parameters. In this paper, an implementation of the metal-backed free-space technique, based on the employment of antenna probes, is utilized for the characterization of composite materials that belong to an actual drone. Their extracted properties are compared with those given by a commercial solution, an open-ended coaxial probe (OECP). The discrepancies found between both techniques along with a further evaluation of the methodologies, including measurements with a split-cavity resonator, conclude that the implemented free-space technique provides more reliable results for this kind of composites than the OECP technique
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Complex permittivity estimation by bio-inspired algorithms for target identification improvement
(Springer Link, 2007-05-14) Poyatos Martínez, D.; Escot Bocanegra, D.; Montiel, I.; Olmeda, I.; Instituto Nacional de Técnica Aeroespacial (INTA)
Identification of aircrafts by means of radar when no cooperation exists (Non-Cooperative Target Identification, NCTI) tends to be based on simulations. To improve them, and hence the probability of correct identification, right values of permittivity and permeability need to be used. This paper describes a method for the estimation of the electromagnetic properties of materials as a part of the NCTI problem. Different heuristic optimization algorithms such as Genetic Algorithms (GA) and Particle Swarm Optimization (PSO), as well as other approaches like Artificial Neural Networks (ANN), are applied to the reflection coefficient obtained via free-space measurements in an anechoic chamber. Prior to the comparison with real samples, artificial synthetic materials are generated to test the performance of these bio-inspired algorithms.
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Design of a planetary protection cover for EMC testing of a spacial magnetic sensor
(Institute of Electrical and Electronics Engineers, 2019-10-17) Fernández Romero, S.; Parrondo, M. C.; Díaz Michelena, M.; Muñóz Rebate, I.; León Calero, Marina; Martín Iglesias, S.; Plaza Gallardo, B.; Escot Bocanegra, D.; Poyatos Martínez, D.; Jiménez Lorenzo, María; López Sanz, Daniel; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI)
This paper explains the research process carried out for the development and manufacture of the planetary protection cover for carrying out the electromagnetic compatibility (EMC) tests of the an-isotropic magneto-resistance (AMR) sensor of the ExoMars 2020 mission. This mission has strict bioburden requirements. The electromagnetic properties of several materials have been analyzed in order to study their transmission coefficient and the innovation of this project is the use of fused deposition modeling (FDM) technology as manufacturing method. Additive manufacturing is presented as a promising technology in the field of radiofrequency since it can use a wide range of polymeric materials (thermoplastics) with low transmission coefficient. Observing the electromagnetic (EM) characterization results, it was decided to manufacture a protective cover using FDM technology, because it allows control over the grounding of the instrument and facilitates the integration, cleaning and protection against impacts during the manipulation, with great versatility and low cost. Finally, the cover has been verified during the acceptance EMC tests of the flight model AMR instrument.
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EPOD: Jammer de bajo consumo y coste para UAS y aviones blanco
(Ministerio de Defensa: Secretaria General Técnica, 2013-11-07) De Diego Custodio, E.; Escot Bocanegra, D.; Aguilar Rosado, Juan Angel; González Diego, I.; Instituto Nacional de Técnica Aeroespacial (INTA)
EPOD es el primer sistema de guerra electrónica (jamming) de bajo consumo y coste, específicamente diseñado para UAVs y aviones blanco. El sistema es reconfigurable en vuelo de manera remota, lo que permite la reprogramación de diferentes contramedidas y modos de funcionamiento. Además, está dotado de una gran versatilidad para ser instalado en cualquier UAS. El sistema puede operar con sub-bandas específicas S, C, X, Ku, o multibanda y entre sus modos de operación destacan RGPO, VGPO, control de RCS dinámica y estática, modulaciones vectoriales dinámicas y estáticas reconfigurables y ruido. El bajo peso del sistema completo (como máximo 5Kg de peso, incluidas las baterías) y su fácil y flexible instalación en diversas plataformas aéreas, hacen que dicho equipo de GE sea ideal para su instalación tanto en aviones blanco de prestaciones medias como altas.
Acceso Abierto
Evaluación de algoritmos de identificación no cooperativa de blancos aéreos mediante perfiles de alta resolución
(Ministerio de Defensa: Secretaria General Técnica, 2018-11-20) Hernán Vega, O.; López Rodríguez, P.; Escot Bocanegra, D.; Poyatos Martínez, D.; Fernández Recio, R.; Bravo, I.
El principal desafío tecnológico relacionado con la Seguridad y Defensa es la identificación de forma rápida y fiable de diferentes aeronaves en vuelo. La identificación no cooperativa de blancos aéreos basada en perfiles en distancia de alta resolución, permite conocer si un blanco es amigo o enemigo sin necesidad de establecer un enlace de comunicación con él. Este artículo presenta la simulación de un sistema de reconocimiento basado en la aplicación de la descomposición de valores singulares a un conjunto de perfiles sintéticos, para extraer sus características principales. Mediante esta técnica, cada blanco se modela como un subespacio, y de esta manera es posible trabajar con la información más significativa en el dominio transformado, reduciendo efectos no deseados como el ruido u otras posibles interferencias.
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Evaluation of particle swarm optimization applied to single snapshot direction of arrival estimation
(Taylor and Francis Online, 2012-04-03) Poyatos Martínez, D.; Escot Bocanegra, D.; González Santamaría, I.; Sáez de Adana, F.; Cátedra, M. F.; Instituto Nacional de Técnica Aeroespacial (INTA)
A heuristic solver such as particle swarm optimization (PSO) is used for single snapshot direction of arrival (DOA) estimation of a set of signals impinging on a uniform linear array (ULA). A performance analysis for infinite signal-to-noise ratio (SNR) shows the validity of this approach and an example using signal and ULA parameters from a more realistic DOA problem is also included.
Acceso Abierto
Firma Radar de Vehículos Aéreos no Tripulados: Revisión de datos publicados y tendencias actuales
(Ministerio de Defensa: Secretaria General Técnica, 2018-10-23) Jenaro, G.; Poyatos Martínez, D.; Escot Bocanegra, D.; Agencia Estatal de Investigación (AEI)
En la actualidad, Lla detección temprana de las plataformas aéreas no tripuladas y a su vez la reducción de la detectabilidad indetectabilidad de las propias es imprescindible en los ámbitos de Defensa y Seguridad para la seguridad. La probabilidad de detección de una plataforma aérea no tripulada (UAV) mediante radar depende en gran medida de su firma radar, también denominada sección transversal radar (Radar Cross Section - RCS). Este valor puede llegar a ser muy pequeño, especialmente en sistemas tipo Mini y Micro UAV, hasta el punto de que estos sistemas pueden tener una RCS comparable a la de los pájaros. Además, las señales procedentes del terreno (background clutter), la frecuencia del radar, la velocidad radial y la trayectoria seguida por el UAV pueden hacer aún más difícil la detección. Diversas técnicas, como por ejemplo el análisis micro-Doppler, permiten identificar a las plataformas. En este artículo se hace una revisión de las líneas de investigación y los datos publicados en este campo, y se esbozan muestran las principales líneas de trabajo, por un lado, para conocer las características de reflectividad de varios UAVs operativos, y por otro lado para definir las metodologías de reducción de la sección transversal radar de los nuevos sistemas.
Acceso Abierto
FS electromagnetic characterisation of a flexible and scalable X-band RAM
(The Institution of Engeering and Technology, 2018-03-12) Aguirre, A.; Torres de Pedro, C.; Plaza Gallardo, B.; Poyatos Martínez, D.; Escot Bocanegra, D.; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); Universidad Nacional de San Martín (UNSAM)
Along the years, RADAR absorbing materials (RAM's) have been widely introduced in aeronautic applications and platforms. However, this kind of materials presents three main problems for certain applications when they are intended to be used in real operations. First, they must be scalable from a laboratory sample to actual size, at a reasonable cost. Second, they must be able to work without metal backing for applications in non-metallic vehicles or other objects which surface might not be flat. Indeed, they should also be flexible and surface adaptable. Finally, their absorbing properties against electromagnetic fields should be preferably characterised under real conditions, that is, in free space (FS), in order to design and fabricate an appropriate material for the intended application. In this study, a self-developed, low-cost, bilayer, X-band RAM, composed of a lower layer of polyaniline silicon rubber and a top layer of silicon rubber with graphite was characterised in a bistatic anechoic chamber called BIANCHA, and the results are presented, analysed and compared with software simulation and with the typical single polarisation waveguide measurement method, showing the adequacy of FS measurements for the development of this type of RAM.
Restringido
Identificación no cooperativa de blancos reales aéreos mediante radar utilizando una base de datos sintética y descomposición en valores singulares
(Ministerio de Defensa: Secretaria General Técnica, 2013-11-07) López Rodríguez, P.; Fernández Recio, R.; Bravo, I.; De Diego Custodio, E.; Poyatos Martínez, D.; Escot Bocanegra, D.; Instituto Nacional de Técnica Aeroespacial (INTA)
El reconocimiento de blancos aéreos no cooperativos mediante perfiles de alta resolución es un procedimiento de gran interés en el ámbito de la defensa. La creación de la base de datos para el reconocimiento a partir de simulaciones electromagnéticas es un tema recursivo en el mundo de la identificación no cooperativa. Se trata de una solución de bajo coste que permite tener información de todos los posibles blancos, rangos de frecuencia y diferentes ángulos de aspecto. Sin embargo, el uso de simulaciones electromagnéticas como base de datos en el reconocimiento de aviones reales hace del proceso una tarea complicada. Mediante la descomposición en valores singulares de un conjunto de perfiles se consigue la reducción de dimensionalidad añadiendo la capacidad de trabajar en el dominio transformado para realizar el proceso de identificación. La principal dificultad de este estudio estriba en el reconocimiento de medidas reales con la utilización de una base de datos construida sintéticamente mediante simulaciones electromagnéticas de modelos CAD de aeronaves.