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Wang, Bin, Shunan Wang, Dan Zeng e Min Wang. "Convolutional Neural Network-Based Radar Antenna Scanning Period Recognition". Electronics 11, n. 9 (26 aprile 2022): 1383. http://dx.doi.org/10.3390/electronics11091383.
Testo completoAbstract (sommario):
The antenna scanning period (ASP) of radar is a crucial parameter in electronic warfare (EW) which is used in many applications, such as radar work pattern recognition and emitter recognition. For antennas of radars and EW systems, which perform scanning circularly, the method based on threshold measurement is invalid. To overcome this shortcoming, this study proposes a method using the convolutional neural network (CNN) to recognize the ASP of radar under the condition that antennas of the radar and EW system both scan circularly. A system model is constructed, and factors affecting the received signal power are analyzed. A CNN model for rapid and accurate ASP radar classification is developed. A large number of received signal time–power images of three separate ASPs are used for the training and testing of the developed model under different experimental conditions. Numerical experiment results and performance comparison demonstrate high classification accuracy and effectiveness of the proposed method in the condition that antennas of radar and EW system are circular scan, where the average recognition accuracy for radar ASP is at least 90% when the signal to-noise ratio (SNR) is not less than 30 dB, which is significantly higher than the recognition accuracy of NAC and AFT methods based on adaptive threshold detection.
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Wang, Bin, Shunan Wang, Dan Zeng e Min Wang. "Convolutional Neural Network-Based Radar Antenna Scanning Period Recognition". Electronics 11, n. 9 (26 aprile 2022): 1383. http://dx.doi.org/10.3390/electronics11091383.
Testo completoAbstract (sommario):
The antenna scanning period (ASP) of radar is a crucial parameter in electronic warfare (EW) which is used in many applications, such as radar work pattern recognition and emitter recognition. For antennas of radars and EW systems, which perform scanning circularly, the method based on threshold measurement is invalid. To overcome this shortcoming, this study proposes a method using the convolutional neural network (CNN) to recognize the ASP of radar under the condition that antennas of the radar and EW system both scan circularly. A system model is constructed, and factors affecting the received signal power are analyzed. A CNN model for rapid and accurate ASP radar classification is developed. A large number of received signal time–power images of three separate ASPs are used for the training and testing of the developed model under different experimental conditions. Numerical experiment results and performance comparison demonstrate high classification accuracy and effectiveness of the proposed method in the condition that antennas of radar and EW system are circular scan, where the average recognition accuracy for radar ASP is at least 90% when the signal to-noise ratio (SNR) is not less than 30 dB, which is significantly higher than the recognition accuracy of NAC and AFT methods based on adaptive threshold detection.
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Wang, Bin, Shunan Wang, Dan Zeng e Min Wang. "Convolutional Neural Network-Based Radar Antenna Scanning Period Recognition". Electronics 11, n. 9 (26 aprile 2022): 1383. http://dx.doi.org/10.3390/electronics11091383.
Testo completoAbstract (sommario):
The antenna scanning period (ASP) of radar is a crucial parameter in electronic warfare (EW) which is used in many applications, such as radar work pattern recognition and emitter recognition. For antennas of radars and EW systems, which perform scanning circularly, the method based on threshold measurement is invalid. To overcome this shortcoming, this study proposes a method using the convolutional neural network (CNN) to recognize the ASP of radar under the condition that antennas of the radar and EW system both scan circularly. A system model is constructed, and factors affecting the received signal power are analyzed. A CNN model for rapid and accurate ASP radar classification is developed. A large number of received signal time–power images of three separate ASPs are used for the training and testing of the developed model under different experimental conditions. Numerical experiment results and performance comparison demonstrate high classification accuracy and effectiveness of the proposed method in the condition that antennas of radar and EW system are circular scan, where the average recognition accuracy for radar ASP is at least 90% when the signal to-noise ratio (SNR) is not less than 30 dB, which is significantly higher than the recognition accuracy of NAC and AFT methods based on adaptive threshold detection.
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MARUDDANI, BASO, EFRI SANDI EFRI SANDI e MUHAMMAD FADHIL NAUFAL SALAM. "Perancangan dan Optimasi Antena Vivaldi pada Sistem Radar Penembus Permukaan (Ground Penetrating Radar)". ELKOMIKA: Jurnal Teknik Energi Elektrik, Teknik Telekomunikasi, & Teknik Elektronika 7, n. 1 (24 gennaio 2019): 151. http://dx.doi.org/10.26760/elkomika.v7i1.151.
Testo completoAbstract (sommario):
ABSTRAKAntena Vivaldi merupakan salah satu jenis antena yang diimplementasikan pada radar penembus permukaan (Ground Penetrating Radar, GPR). GPR adalah salah satu metode non-destructive testing yang biasa digunakan untuk mengetahui kondisi beton/jalan raya. Penelitian ini merancang sebuah antena Vivaldi untuk digunakan pada GPR dengan frekuensi kerja 1 GHz – 2 GHz. Metode yang digunakan untuk merancang dan mengoptimasi antena Vivaldi adalah dengan mengubah beberapa parameter untuk mencapai spesifikasi yang diinginkan. Parameter tersebut antara lain lebar antena, panjang antena dan tapered slot. Optimasi yang dilakukan tetap memperhatikan pola radiasi antena agar tetap terarah. Hasil penelitian ini menghasilkan antena Vivaldi dengan dimensi 350x300 mm dengan return loss di bawah -10 dB pada rentang frekuensi 1 GHz – 2 GHz. Hasil penelitian juga menunjukkan bahwa perubahan nilai parameter lebar antena dan tapered slot menggeser frekuensi kerja antena secara signifikan.Kata kunci: Ground Penetrating Radar, Vivaldi, return loss, parameter antena ABSTRACTThe Vivaldi antenna is one type of antenna that is implemented on Ground Penetrating Radar (GPR). GPR is one of the non-destructive testing methods commonly used to determine the condition of concrete / highway. This studyaim to design a Vivaldi antenna to be used on GPR with a working frequency of 1 GHz - 2 GHz. The method that used to design and optimize Vivaldi antennas is by changing several parameters to achieve the desired specifications. These parameters include antenna width, antenna length and tapered slot. Optimization carried out still observes the radiation pattern of the antenna to keep it directed. The results showed that 350 x 300 mm antennas with return loss below -10 dB in the frequency range of 1 GHz - 2 GHz. The results also show that changes in the parameter width of the antenna and tapered slots shift the antenna working frequency significantly.Keywords: Ground Penetrating Radar, Vivaldi, return loss, antenna parameter
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Chipengo, Ushemadzoro, Peter M. Krenz e Shawn Carpenter. "From Antenna Design to High Fidelity, Full Physics Automotive Radar Sensor Corner Case Simulation". Modelling and Simulation in Engineering 2018 (27 dicembre 2018): 1–19. http://dx.doi.org/10.1155/2018/4239725.
Testo completoAbstract (sommario):
Advanced driver assistance systems (ADAS) have recently been thrust into the spotlight in the automotive industry as carmakers and technology companies pursue effective active safety systems and fully autonomous vehicles. Various sensors such as lidar (light detection and ranging), radar (radio detection and ranging), ultrasonic, and optical cameras are employed to provide situational awareness to vehicles in a highly dynamic environment. Radar has emerged as a primary sensor technology for both active/passive safety and comfort-advanced driver-assistance systems. Physically building and testing radar systems to demonstrate reliability is an expensive and time-consuming process. Simulation emerges as the most practical solution to designing and testing radar systems. This paper provides a complete, full physics simulation workflow for automotive radar using finite element method and asymptotic ray tracing electromagnetic solvers. The design and optimization of both transmitter and receiver antennas is presented. Antenna interaction with vehicle bumper and fascia is also investigated. A full physics-based radar scene corner case is modelled to obtain high-fidelity range-Doppler maps. Finally, this paper investigates the effects of inclined roads on late pedestrian detection and the effects of construction metal plate radar returns on false target identification. Possible solutions are suggested and validated. Results from this study show how pedestrian radar returns can be increased by over 16 dB for early detection along with a 27 dB reduction in road construction plate radar returns to suppress false target identification. Both solutions to the above corner cases can potentially save pedestrian lives and prevent future accidents.
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Bernatek-Jakiel, Anita, e Marta Kondracka. "Detection of Soil Pipes Using Ground Penetrating Radar". Remote Sensing 11, n. 16 (9 agosto 2019): 1864. http://dx.doi.org/10.3390/rs11161864.
Testo completoAbstract (sommario):
Soil piping leads to land degradation in almost all morphoclimatic regions. However, the detection of soil pipes is still a methodological challenge. Therefore, this study aims at testing ground penetrating radar (GPR) to identify soil pipes and to present the complexity of soil pipe networks. The GPR surveys were conducted at three sites in the Bieszczady Mountains (SE Poland), where pipes develop in Cambisols. In total, 36 GPR profiles longitudinal and transverse to piping systems were made and used to provide spatial visualization of pipe networks. Soil pipes were identified as reflection hyperbolas on radargrams, which were verified with the surface indicators of piping, i.e., sagging of the ground and the occurrence of pipe roof collapses. Antennas of 500 MHz and 800 MHz were tested, which made possible the penetration of the subsurface up to 3.2 m and 2 m, respectively. Concerning ground properties, antenna frequencies and processing techniques, there was a potential possibility to detect pipes with a minimum diameter of 3.5 cm (using the antenna of lower frequency), and 2.2 cm (with the antenna of higher frequency). The results have proved that soil pipes meander horizontally and vertically and their networks become more complicated and extensive down the slope. GPR is a useful method to detect soil pipes, although it requires field verification and the proper selection of antenna frequency.
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Langston, Glen. "NRAO 43-m telescope operation at 170-1700 MHz: a Bi-Static Radar Collaboration". Proceedings of the International Astronomical Union 2, n. 14 (agosto 2006): 367. http://dx.doi.org/10.1017/s1743921307011015.
Testo completoAbstract (sommario):
AbstractThe NRAO 43m telescope has been refurbished and begun regular observations in the frequency range 170 - 1700 MHz. The 43 m operations support a Bi-Static Radar Collaboration to measure the Earth's ionospheric turbulence. Researchers from Chalmers University of Technology in Sweden have designed and built a unique design wide-band feed, 150 - 1700 MHz. Lincoln Laboratories/MIT has packaged the feed with room temperature low noise amplifiers. Lincoln Laboratories has installed a high-dynamic range RF system together with a wide-band sampler system. The NRAO operates the 43 m telescope according to schedules authored by Lincoln Laboratories. Currently the 43 m telescope is tracking spacecraft 48 hr a week. The tracking antenna operation is completely automated. A group at MIT/Haystack have installed a second radar experiment at the 43 m as well as an array of 6 ‘discone’ antennas. Their experiment is testing the use of reflected FM radio stations as probes of the ionosphere.
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Galajda, Pavol, Alena Galajdova, Stanislav Slovak, Martin Pecovsky, Milos Drutarovsky, Marek Sukop e Ihab BA Samaneh. "Robot vision ultra-wideband wireless sensor in non-cooperative industrial environments". International Journal of Advanced Robotic Systems 15, n. 4 (1 luglio 2018): 172988141879576. http://dx.doi.org/10.1177/1729881418795767.
Testo completoAbstract (sommario):
In this article, the ultra-wideband technology for localization and tracking of the robot gripper (behind the obstacles) in industrial environments is presented. We explore the possibilities of ultra-wideband radar sensor network employing the centralized data fusion method that can significantly improve tracking capabilities in a complex environment. In this article, we present ultra-wideband radar sensor network hardware demonstrator that uses a new wireless ultra-wideband sensor with an embedded controller to detect and track online or off-line movement of the robot gripper. This sensor uses M-sequence ultra-wideband radars front-end and low-cost powerful processors on a system on chip with the advanced RISC machines (ARM) architecture as a main signal processing block. The ARM-based single board computer ODROID-XU4 platform used in our ultra-wideband sensor can provide processing power for the preprocessing of received raw radar signals, algorithms for detection and estimation of target’s coordinates, and finally, compression of data sent to the data fusion center. Data streams of compressed target coordinates are sent from each sensor node to the data fusion center in the central node using standard the wireless local area network (WLAN) interface that is the feature of the ODROID-XU4 platform. The article contains experimental results from measurements where sensors and antennas are located behind the wall or opaque material. Experimental testing confirmed capability of real-time performance of developed ultra-wideband radar sensor network hardware and acceptable precision of software. The introduced modular architecture of ultra-wideband radar sensor network can be used for fast development and testing of new real-time localization and tracking applications in industrial environments.
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Pryshchenko, Oleksandr A., Vadym Plakhtii, Oleksandr M. Dumin, Gennadiy P. Pochanin, Vadym P. Ruban, Lorenzo Capineri e Fronefield Crawford. "Implementation of an Artificial Intelligence Approach to GPR Systems for Landmine Detection". Remote Sensing 14, n. 17 (5 settembre 2022): 4421. http://dx.doi.org/10.3390/rs14174421.
Testo completoAbstract (sommario):
Artificial Neural Network (ANN) approaches are applied to detect and determine the object class using a special set of the UltraWideBand (UWB) pulse Ground Penetrating Radar (GPR) sounding results. It used the results of GPR sounding with the antenna system, consisting of one radiator and four receiving antennas located around the transmitting antenna. The presence of four receiving antennas and, accordingly, the signals received from four spatially separated positions of the antennas provide a collection of signals received after reflection from an object at different angles and, due to this, to determine the location of the object in a coordinate system, connected to the antenna. We considered the sums and differences of signals received by two of the four antennas in six possible combinations: (1 and 2, 1 and 3, 2 and 3, 1 and 4, etc.). These combinations were then stacked sequentially one by one into one long signal. Synthetic signals constructed in such a way contain many more notable differences and specific information about the class to which the object belongs as well as the location of the searched object compared to the signals obtained by an antenna system with just one radiating and one receiving antenna. It therefore increases the accuracy in determining the object’s coordinates and its classification. The pulse radiation, propagation, and scattering are numerically simulated by the finite difference time domain (FDTD) method. Results from the experiment on mine detection are used to examine ANN too. The set of signals from different objects having different distances from the GPR was used as a training and testing dataset for ANN. The training aims to recognize and classify the detected object as a landmine or other object and to determine its location. The influence of Gaussian noise added to the signals on noise immunity of ANN was investigated. The recognition results obtained by using an ANN ensemble are presented. The ensemble consists of fully connected and recurrent neural networks, gated recurrent units, and a long-short term memory network. The results of the recognition by all ANNs are processed by a meta network to provide a better quality of underground object classification.
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Ajith, K. K., e Amitabha Bhattacharya. "Improving the GPR Detectability Using a Novel Loop Bowtie Antenna". Journal of Telecommunications and Information Technology, n. 3 (2017): 9–16. http://dx.doi.org/10.26636/jtit.2017.120917.
Testo completoAbstract (sommario):
The Ground Penetrating Radar (GPR) technique finds immense applications in civil engineering today, as the most suitable approach for non-destructive testing of pavements, highways, concrete structures, and more. The major challenge in carrying out a GPR evaluation is that the properties of the probed medium are usually unknown. The permittivity and conductivity of the medium may vary from those of air to water. The electromagnetic waves also have a frequency dependent attenuation. The ability of GPR to detect signals reflected and scattered by the targets largely depends upon the antenna performance. This paper studies a novel 11:1 wideband loop bowtie antenna with very good radiation properties in the entire operating bandwidth. Synthetic and experimental results are presented for the return loss and gain of the antenna. Furthermore, experimental results are presented for the radiation patterns in the E- and H-plane. We also used the antenna to measure B-scans over two different pipes, a bamboo, and a reinforced concrete structure. All results obtained with the proposed antenna have been compared with results obtained by using a RC loaded antenna. It has been found that the loop bowtie antenna has excellent detection capability and produces less clutter. The loop loading technique can be applied to existing antennas for improved GPR imaging. This will improve the detectability of GPR by improving the target return signal.
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Ionescu, Liviu, Alexandru Rusu-Casandra, Calin Bira, Alexandru Tatomirescu, Ionut Tramandan, Roberto Scagnoli, Dan Istriteanu e Andrei-Edward Popa. "Development of the Romanian Radar Sensor for Space Surveillance and Tracking Activities". Sensors 22, n. 9 (6 maggio 2022): 3546. http://dx.doi.org/10.3390/s22093546.
Testo completoAbstract (sommario):
The constant increase in the number of space objects and debris orbiting the Earth poses risks to satellites and other spacecraft, both in orbit and during the launching process. Therefore, the monitoring of space hazards to assess risk and prevent collisions has become part of the European Space Policy and requires the establishment of a dedicated Framework for Space Surveillance and Tracking (EU SST) Support. This article presents the CHEIA SST Radar, a new space tracking radar sensor developed and installed in Romania with the purpose of being included in the EU SST sensor network and of contributing to the joint database of space objects orbiting the Earth. The paper describes the processes of design, simulation, and implementation of the hardware and software building blocks that make up the radar system. It emphasizes the particular case of using an already existing system of two large parabolic antennas requiring an innovative retrofitting design to include them as the basis for a new quasi-monostatic radar using LFMCW probing signals. The preliminary design was validated by extensive simulations, and the initial operational testing carried out in December 2021 demonstrated the good performance of the radar in the measuring range and radial speed of LEO space objects.
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Wassie, Y., M. Crosetto, G. Luzi, O. Monserrat, A. Barra, R. Palamá, M. Cuevas-González, S. M. Mirmazloumi, P. Espín-López e B. Crippa. "ACTIVE REFLECTORS FOR INTERFEROMETRIC SAR DEFORMATION MEASUREMENT". International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B3-2021 (28 giugno 2021): 177–82. http://dx.doi.org/10.5194/isprs-archives-xliii-b3-2021-177-2021.
Testo completoAbstract (sommario):
Abstract. This paper is focused on the design, implementation and testing of an active reflector, to be used to support deformation monitoring studies based on Synthetic Aperture Radar interferometry. The device is designed to work in C-band with Sentinel-1 data, operating at 5.405 GHz ± 50 MHz. A brief description of the active reflector is provided. It consists of two antennas and an amplifying section. The active reflector has been tested in different experiments. In this paper, we describe the experiment carried out in the Parc Mediterrani de la Tecnologia (Castelldefels, Barcelona). The result shows a strong correlation with temperature. A calibration test was carried out to experimentally derive a calibration curve to correct the effect of temperature on phase stability.
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Choudhary, Vipin, e Daniel Rönnow. "A Nondestructive Testing Method for the Determination of the Complex Refractive Index Using Ultra Wideband Radar in Industrial Applications". Sensors 20, n. 11 (2 giugno 2020): 3161. http://dx.doi.org/10.3390/s20113161.
Testo completoAbstract (sommario):
An ultra-wide band radar reflection measurement technique for industrial applications is introduced. A new method for determining the complex refractive index (or equivalently the relative permittivity) of objects with planar interfaces is presented. The object thickness can also be obtained experimentally. The method is a combination of time and frequency domain techniques. The objects can be finite in size and at a finite distance. The limits in size and distance for the method to be valid are experimentally investigated. The method is relatively insensitive to hardware impairments such as frequency dependence of antennas and analog front end. The method is designed for industrial in-line measurements on objects on conveyor belts. Results are presented for solid wood and wood chips; the complex refractive index is determined in the frequency range 0.5 to 2.0 GHz for the moisture content of 3.6–10% for solid wood and 30–50% for wood chips. Polarimetric measurements are used; wood and wood chips are anisotropic.
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Holt, J. M., P. J. Erickson, A. M. Gorczyca e T. Grydeland. "MIDAS-W: a workstation-based incoherent scatter radar data acquisition system". Annales Geophysicae 18, n. 9 (30 settembre 2000): 1231–41. http://dx.doi.org/10.1007/s00585-000-1231-3.
Testo completoAbstract (sommario):
Abstract. The Millstone Hill Incoherent Scatter Data Acquisition System (MIDAS) is based on an abstract model of an incoherent scatter radar. This model is implemented in a hierarchical software system, which serves to isolate hardware and low-level software implementation details from higher levels of the system. Inherent in this is the idea that implementation details can easily be changed in response to technological advances. MIDAS is an evolutionary system, and the MIDAS hardware has, in fact, evolved while the basic software model has remained unchanged. From the earliest days of MIDAS, it was realized that some functions implemented in specialized hardware might eventually be implemented by software in a general-purpose computer. MIDAS-W is the realization of this concept. The core component of MIDAS-W is a Sun Microsystems UltraSparc 10 workstation equipped with an Ultrarad 1280 PCI bus analog to digital (A/D) converter board. In the current implementation, a 2.25 MHz intermediate frequency (IF) is bandpass sampled at 1 µs intervals and these samples are multicast over a high-speed Ethernet which serves as a raw data bus. A second workstation receives the samples, converts them to filtered, decimated, complex baseband samples and computes the lag-profile matrix of the decimated samples. Overall performance is approximately ten times better than the previous MIDAS system, which utilizes a custom digital filtering module and array processor based correlator. A major advantage of MIDAS-W is its flexibility. A portable, single-workstation data acquisition system can be implemented by moving the software receiver and correlator programs to the workstation with the A/D converter. When the data samples are multicast, additional data processing systems, for example for raw data recording, can be implemented simply by adding another workstation with suitable software to the high-speed network. Testing of new data processing software is also greatly simplified, because a workstation with the new software can be added to the network without impacting the production system. MIDAS-W has been operated in parallel with the existing MIDAS-1 system to verify that incoherent scatter measurements by the two systems agree. MIDAS-W has also been used in a high-bandwidth mode to collect data on the November, 1999, Leonid meteor shower.Key words: Electromagnetics (instruments and techniques; signal processing and adaptive antennas) – Ionosphere (instruments and techniques)
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Kyzioł, Lesław, Katarzyna Panasiuk, Grzegorz Hajdukiewicz e Krzysztof Dudzik. "Acoustic Emission and K-S Metric Entropy as Methods for Determining Mechanical Properties of Composite Materials". Sensors 21, n. 1 (28 dicembre 2020): 145. http://dx.doi.org/10.3390/s21010145.
Testo completoAbstract (sommario):
Due to the unique properties of polymer composites, these materials are used in many industries, including shipbuilding (hulls of boats, yachts, motorboats, cutters, ship and cooling doors, pontoons and floats, torpedo tubes and missiles, protective shields, antenna masts, radar shields, and antennas, etc.). Modern measurement methods and tools allow to determine the properties of the composite material, already during its design. The article presents the use of the method of acoustic emission and Kolmogorov-Sinai (K-S) metric entropy to determine the mechanical properties of composites. The tested materials were polyester-glass laminate without additives and with a 10% content of polyester-glass waste. The changes taking place in the composite material during loading were visualized using a piezoelectric sensor used in the acoustic emission method. Thanks to the analysis of the RMS parameter (root mean square of the acoustic emission signal), it is possible to determine the range of stresses at which significant changes occur in the material in terms of its use as a construction material. In the K-S entropy method, an important measuring tool is the extensometer, namely the displacement sensor built into it. The results obtained during the static tensile test with the use of an extensometer allow them to be used to calculate the K-S metric entropy. Many materials, including composite materials, do not have a yield point. In principle, there are no methods for determining the transition of a material from elastic to plastic phase. The authors showed that, with the use of a modern testing machine and very high-quality instrumentation to record measurement data using the Kolmogorov-Sinai (K-S) metric entropy method and the acoustic emission (AE) method, it is possible to determine the material transition from elastic to plastic phase. Determining the yield strength of composite materials is extremely important information when designing a structure.
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Guliyev, Etibar, Rashad Allahverdiyev e Qezale Kheyrabadi. "Identification of the patterns of influence the number of reinforcing elements and the inhomogeneity parameter of the shell material on frequencies of a reinforced inhomogeneous orthotropic spherical shell with a medium". Eastern-European Journal of Enterprise Technologies 5, n. 7 (119) (31 ottobre 2022): 35–43. http://dx.doi.org/10.15587/1729-4061.2022.266166.
Testo completoAbstract (sommario):
Spherical shells are used in many areas of the national economy. Spherical domes are widely used in the construction of various structures (technoparks, testing laboratories, entertainment complexes, reservoirs, etc.). They are also used in aircraft, ship structures, radar antennas and other structures. It is known that coatings have sufficient strength and durability even with a small thickness. However, to increase the working life of coatings, to ensure their long-term operation, as well as to increase their hardness, it is necessary to strengthen them on the surface or inside with rods. Sometimes it is possible to reduce the weight of the structure and save material consumption by strengthening it with. One of the advantages of these structures is that they give the maximum useful volume, being both load-bearing and enclosing structures. Checking the shells for stability is a priority task, since it is known that the shells, even with an insignificant thickness, have great strength and therefore their insufficient stability can be a criterion determining the bearing capacity. This article is devoted to identifying the regularities of the influence of the number of reinforcing elements and the inhomogeneity parameter of the shell material on the frequencies supported by an inhomogeneous orthotropic spherical shell with a medium. To solve the problem under consideration, the Hamilton-Ostrogradsky variation principle is applied. The frequency equation is constructed and implemented numerically. Such studies have not been considered for a reinforced spherical shell with a no uniform filler in thickness
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Konopel'kin, M. Yu, S. V. Petrov e D. A. Smirnyagina. "Implementation of stochastic signal processing algorithms in radar CAD". Russian Technological Journal 10, n. 5 (21 ottobre 2022): 49–59. http://dx.doi.org/10.32362/2500-316x-2022-10-5-49-59.
Testo completoAbstract (sommario):
Objectives. In 2020, development work on the creation of a Russian computer-assisted design system for radars (radar CAD) was completed. Radar CAD provides extensive opportunities for creating simulation models for developing the hardware-software complex of radar algorithms, which take into account the specific conditions of aerospace environment observation. The purpose of the present work is to review and demonstrate the capabilities of radar CAD in terms of implementing and testing algorithms for processing stochastic signals.Methods. The work is based on the mathematical apparatus of linear algebra. Analysis of algorithms characteristics was carried out using the simulation method.Results. A simulation model of a sector surveillance radar with a digital antenna array was created in the radar CAD visual functional editor. The passive channel included the following algorithms: algorithm for detecting stochastic signals; algorithm for estimating the number of stochastic signals; direction finding algorithm for stochastic signal sources; adaptive spatial filtering algorithm. In the process of simulation, the algorithms for detecting and estimating the number of stochastic signals produced a correct detection sign and an estimate of the number of signals. The direction-finding algorithm estimated the angular position of the sources with an accuracy of fractions of degrees. The adaptive spatial filtering algorithm suppressed interfering signals to a level below the antenna's intrinsic noise power.Conclusions. The processing of various types of signals can be simulated in detail on the basis of the Russian radar CAD system for the development of functional radar models. According to the results of the simulation, coordinates of observing objects were obtained and an assessment of the effectiveness of the algorithms was given. The obtained results are fully consistent with the theoretical prediction. The capabilities of radar CAD systems demonstrated in this work can be used by specialists in the field of radar and signal processing.
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Zhou, Daochuan, e Haitang Zhu. "Application of Ground Penetrating Radar in Detecting Deeply Embedded Reinforcing Bars in Pile Foundation". Advances in Civil Engineering 2021 (17 aprile 2021): 1–13. http://dx.doi.org/10.1155/2021/4813415.
Testo completoAbstract (sommario):
Ground penetrating radar (GPR) has been widely used for nondestructive testings in civil engineering. However, the GPR has not been adequately applied in detecting deeply embedded reinforcing bars, which is usually difficult to be revealed in radar image due to the wave interference and attenuation in large depth penetration. This study presents a new approach for the GPR detection of deeply embedded reinforcing bars in the reinforced concrete pile foundation. The aim of the GPR survey is to determine the existence and the depth of internal reinforcing bars in the pile foundation for solving engineering dispute. Low centre frequency antenna was used in GPR field testing to obtain the reflected raw data. Optimized procedures of digital filtering techniques were applied to process the GPR raw data. The deeply embedded reinforcing bars are revealed in the radar image after the field testing and postprocessing procedures. The depth of the reinforcing bars was estimated based on the hyperbola match method. The GPR test results were validated by the excavation of the pile foundation. The low centre frequency antenna has been found to be essential to obtain the reflected wave signals of deeply embedded reinforcing bars. The optimized processing procedures is useful to identify and display the reinforcing bars in radar image. The combination of low centre frequency antenna and the postprocessing procedures make the detection of deeply embedded reinforcing bars feasible. The proposed GPR testing method has been found to be effective to estimate the depth of deeply embedded reinforcing bars, which provides the key information for solving engineering dispute.
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Volosyuk, Valeriy, e Semen Zhyla. "Statistical Theory of Optimal Stochastic Signals Processing in Multichannel Aerospace Imaging Radar Systems". Computation 10, n. 12 (18 dicembre 2022): 224. http://dx.doi.org/10.3390/computation10120224.
Testo completoAbstract (sommario):
The work is devoted to solving current scientific and applied problems of the development of radar imaging methods. These developments are based on statistical theory of optimal signal processing. These developments allow researchers to create coherent high-resolution information-enriched images as well as incoherent images. These methods can be practically applied in multichannel aerospace radars through the proposed programs and algorithms. Firstly, the following models of stochastic signals at the output of multichannel registration regions of scattered electro-magnetic fields, internal noise, and observation equations are developed and their statistical characteristics investigated. For the considered models of observation equations, the likelihood functional is defined. This definition is an important stage in optimizing spatial and temporal signal processing. These signals are distorted by internal receiver noises in radar systems. Secondly, by synthesising and analysing methods of measuring a radar cross section, the problem of incoherent imaging by aerospace radars with planar antenna array is solved. Thirdly, the obtained optimal mathematical operations are physically interpreted. The proposed interpretation helps to implement a quasi-optimal algorithm of radar cross section estimation in aerospace radar systems. Finally, to verify the proposed theory, a semi-natural experiment of real radio holograms processing was performed. These radio holograms are digital recordings of spatial and temporal signals by an airborne synthetic aperture radar (SAR) system. The results of the semi-natural experiment are presented and analysed in the paper. All the calculations, developments and results in this paper can be applied to new developments in areas such as remote sensing or non-destructive testing.
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Mahdi, Sultan, e Syahfrizal Tahcfulloh. "DOA Signal Identification Based on Amplitude and Phase Estimation for Subarray MIMO Radar Applications". Jurnal Elektronika dan Telekomunikasi 22, n. 2 (31 dicembre 2022): 48. http://dx.doi.org/10.55981/jet.498.
Testo completoAbstract (sommario):
The overlapped equal subarray transmit radar, which is also known as the Subarray Multiple-Input Multiple-Output radar, utilizes the key advantages simultaneously of both types of multi-antenna radar, i.e. the phased array and MIMO radars, so that it is able to detect multiple targets even though it has a radar cross section (RCS) of a weak or small target. In this paper, it is proposed to develop a parameter estimation approach called amplitude and phase estimation (APES). This approach provides improved resolution to the estimation of the amplitude and direction of arrival (DoA) of the target reflection signal on the radar compared to the existing conventional estimation methods such as least squares (LS). The formulation of the APES method on this radar is based on the tested parameters such as DoA and RCS and continuously being evaluated. The results show that the performance of the APES method of this radar can detect targets very precisely when the number of subarrays (M) is greater than the number of detection targets (P), precisely M > P. For the results of DoA and RCS accuracy from the APES method, this radar is more accurate than the LS when testing the angular resolution between the two targets, an angle resolution of 2° is obtained for the APES method which is superior to the LS with an angle resolution of 5.8°. In these conditions, the APES method is able to accurately distinguish between two targets while the LS method is only able to detect one target.
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Françoso, Maria Teresa, Carolina Oyama Mota, Tadeu Rosanti Sugahara Medeiros Lima e Creso De Franco Peixoto. "Nondestructive Testing in Asphalt Pavements Using Ground Penetrating Radar (GPR)". Applied Mechanics and Materials 303-306 (febbraio 2013): 525–28. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.525.
Testo completoAbstract (sommario):
This paper presents the results of using the system GPR (Ground Penetrating Radar), as an alternative that uses radio waves at frequencies from 10 to 2500 MHz to get data that enable non-destructive conduct inspections of underground or concrete structures in real time. The research aims to investigate asphalt pavements, analyzing the variations in the responses, which can reveal the presence of pathologies or defects. A case study was made acquiring data, at the State University of Campinas - UNICAMP, in Campinas – SP – Brazil, with antennae 270 and 1600 MHz, in pavements with visible defects of patching and alligator cracks, initially with the dry structure and later, wet. The results were processed in specialized software (Radan 7.0) to generate terrain profiles. The GPR showed effective when there is a change in material employed as in the case of patching, because it was possible to detect layers compromised by intensive request of traffic, the start and end of application of the patching and even deformations in the new layer. In contrast, the alligator cracking did not reach the same result, not presenting accuracy in recognizing the defect. The extent of defect was the only well defined feature in the images.
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Mbotshwa, Cosygyn, Felix Mazunga e Joseph Singadi. "Design, Fabrication and Testing of an Ultra-Wide Band Bowtie Antenna for Wireless Radar (UHF, L and S Band) Communication". International Journal of Advanced Networking and Applications 14, n. 01 (2022): 5261–65. http://dx.doi.org/10.35444/ijana.2022.14104.
Testo completoAbstract (sommario):
A low-cost and light-weight ultra-wideband bowtie antenna for radar applications was simulated, fabricated and tested. A concise and easy to follow step-by-step description of the performed bowtie antenna simulation in Ansys HFSS software is presented. Optimized antenna parameters were utilized to fabricate the antenna. Fabrication was achieved by utilizing an FR4 PCB. The prototype was tested using a spectrum analyzer. The fabricated bowtie antenna results were used to validate the simulation results. The results obtained from the simulation platform were in close agreement to those of the prototype antenna. Results on effect of substrate thickness and frequency on S11 are also presented. The prototype produced improved overall S11 as compared to the simulation. The results indicate that the fabricated antenna satisfies bandwidth requirements for the UHF, L and S bands.
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Yu, Bi Qiong. "Azimuths Scan Servo System Design of the Radar". Applied Mechanics and Materials 321-324 (giugno 2013): 680–83. http://dx.doi.org/10.4028/www.scientific.net/amm.321-324.680.
Testo completoAbstract (sommario):
For the special requirements of the radar antenna, a servo system was designed to drive a certain type of weather radar azimuth scan. The control segment consists of the PC and the stepper motor motion control card, in which the stepper motor was used as the actuator and the motor drive circuit was built by the specific integrated driver chips of the stepper motor. By testing the vibration, the shock and the temperature of system, it shows that the designed azimuths scan servo system can meet the requirements of the weather radar azimuth scan.
24
Ukhanov, E. V. Ukhanov. "SOLVING THE PROBLEM OF OPTIMAL RADAR RECOGNITION OF MOBILE AERIAL OBJECTS BASED ON THE THEORY OF STATISTICAL HYPOTHESIS TESTING". T-Comm 16, n. 11 (2022): 30–34. http://dx.doi.org/10.36724/2072-8735-2022-16-11-30-34.
Testo completoAbstract (sommario):
The materials of this article are devoted to the development of one of the main aspects of artificial intelligence systems - pattern recognition. The relevance of the materials is due to the rapid development of radar systems for various purposes and the transition in some directions from radar to radio vision. Currently, much attention is paid to the development of radar systems with synthesizing the antenna aperture, for remote sensing of the earth and recognition of stationary ground objects, however, according to the author, radar recognition of mobile aerial objects is an important issue. The purpose of this article is to propose a solution to the problem of recognizing moving aerial objects by their radar portraits, based on the theory of statistical hypothesis testing. At the moment there are many methods of pattern recognition, this article discusses an algorithm that implements the function of matching the current image and the reference from a pre-formed catalog. As the current image, an azimuth-range radar portrait is considered, which is formed by super-resolution in azimuth, by synthesizing the aperture of the antenna and in range, using ultra-wideband signal. The author suggests, with a statistical approach to solving the problem of radar recognition, not to be tied to finding the probability of an object belonging to each of the pre-formed classes using a selected feature with a known probability distribution density of values, but to consider this process from the position of the signal at the output of the optimal recognition system to a specific image. A new approach to the description of probabilistic events when making a recognition decision is proposed. As a statistical classifier, it is proposed to use the Neumann-Pearson theory of statistical solutions.
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Spagnolo, Matteo, Edward C. King, David W. Ashmore, Brice R. Rea, Jeremy C. Ely e Chris D. Clark. "Looking through drumlins: testing the application of ground-penetrating rada". Journal of Glaciology 60, n. 224 (2014): 1126–34. http://dx.doi.org/10.3189/2014jog14j110.
Testo completoAbstract (sommario):
AbstractGround-penetrating radar (GPR) is becoming a commonly applied technique in geomorphology. However, its use in the study of subglacial bedforms has yet to be fully explored and exploited. This paper presents the results of a GPR feasibility study conducted on a drumlinized terrain in Cumbria, UK, where five drumlins were investigated using multiple radar antenna frequencies. The site was selected for the presence of nearby bedrock outcrops, suggesting a shallow drumlinized diamict–bedrock contact and a permeable lithology. Despite the clayey sediment and unfavourable weather conditions, a considerable penetration depth of ~12 m was achieved when using a 50 MHz antenna, with a separation of 1 m, trace spacing of 1 m and 128-fold vertical stack. Results indicate that the drumlinized diamict is in direct erosional contact with the bedrock. While the internal drumlin geometry is generally chaotic on the stoss side, evidence of layering dipping downflow at an angle greater than the drumlin surface profile was found on the lee side. The inter-drumlin areas comprise ~4 m of infill sediment that masks part of the original drumlin profile. Overall, this study indicates that GPR can be deployed successfully in the study of glacial bedform sedimentary architecture.
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Ehrnsperger, Matthias G., Uwe Siart, Michael Moosbühler, Emil Daporta e Thomas F. Eibert. "Signal degradation through sediments on safety-critical radar sensors". Advances in Radio Science 17 (19 settembre 2019): 91–100. http://dx.doi.org/10.5194/ars-17-91-2019.
Testo completoAbstract (sommario):
Abstract. This paper focusses on a transmission line (TL) based model which allows to investigate the impact of multilayered obstructions in the propagating path of a radar signal at different distances and in combination with disturbances. Those disturbances can be water, snow, ice, and foliage at different densities, temperatures, positions, with a given thickness and layer combination. For the evaluation of the detectability of objects, the impulse response of the system can be obtained. Investigations employing state-of-the-art radar hardware confirm the consistency of theoretical and experimental results for 24 and 77 GHz. The analysis in this paper supports testing the specifications for radar systems, before carrier frequency and antenna layout are finally decided. Thereby, the radar system parameters can be adjusted toward employed carrier frequency, bandwidth, required sensitivity, antenna and amplifier gain. Since automotive standards define operational environmental conditions such as temperature, rain rate, and layer thickness, these parameters can be included and adapted. A novel optimisation methodology for radomes is presented which allows to boost the dynamic range by almost 6 dB with presence of a worst-case cover layer of water. The findings can be utilised to properly design radar systems for automotive applications in autonomous driving, in which other vulnerable road users have to be protected under all circumstances.
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Lakshmaiah, Akumalla, N. N. S. S. R. K. Prasad e K. P. Ray. "Investigations on Monolithic Radome Interactions with Active Electronically Scanned Array on Fighter Platform". Defence Science Journal 71, n. 5 (2 settembre 2021): 662–69. http://dx.doi.org/10.14429/dsj.71.16398.
Testo completoAbstract (sommario):
The conventional fighter aircrafts are often equipped with fire control radar (FCR) using mechanically scanned antenna (MSA) with passive slots enclosed with monolithic conical radome. When the fighter platforms get upgraded with the modern active electronically steered array (AESA) FCR for better mission capabilities, even though radome change is desirable for optimum performance of AESA, it may not be feasible due to development time. This necessitate the evaluation of AESA radar with the existing monolithic radome. Hence active antenna aperture radiation pattern is required to be assessed with monolithic radome. To address this issue, simulation is preferred over physical testing, due to the reduced cost, time and complexity in measurements and ability to verify compatibility. In the present paper, the influence of monolithic radome on the active antenna radiation patterns are simulated and analysed. The characterisation studies helped for better optimisation of active aperture, optimum size for new radome development and additional space on fighter platforms that can be used for integration of new subsystems. Simulations are performed at two different locations of antenna inside radome. Experimental validations have been carried out to prove the efficacy of simulated results, which are in agreement.
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Norrdine, Abdelmoumen, Harun Cetinkaya e Reinhold Herschel. "Radar Wave Based Positioning of Spatially Distributed MIMO Radar Antenna Systems for Near-Field Nondestructive Testing". IEEE Sensors Letters 4, n. 5 (maggio 2020): 1–4. http://dx.doi.org/10.1109/lsens.2020.2989546.
Testo completo
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Wu, Yuxuan, Feng Shen, Yue Yuan e Dingjie Xu. "An Improved Modified Universal Ultra-Wideband Antenna Designed for Step Frequency Continuous Wave Ground Penetrating Radar System". Sensors 19, n. 5 (1 marzo 2019): 1045. http://dx.doi.org/10.3390/s19051045.
Testo completoAbstract (sommario):
Step Frequency Continuous Wave Ground Penetrating Radar (SFCW-GPR), as a tool for nondestructive testing of shallow soil surface targets, the realization of the function of SFCW-GPR is mainly based on the theory of refraction, reflection and scattering of electromagnetic wave in the discontinuity of dielectric constant. So, the UWB antenna system, an important part of SFCW-GPR, becomes more indispensable. In this paper, an improved modified universal antenna is designed, simulated and fabricated. Based on a typical Bow-tie antenna, it is modified by the methods of lumped loads, cavity-backed loading and structure loading. The simulated and measured results show that the UWB antenna has 1.36 GHz bandwidth from 0.64 to 2.0 GHz with three resonant wavelength peaks, and having been modified and improved, the UWB antenna performances including voltage standing-wave ratio (VSWR), input impedance, the boresight gain and current distribution, are much better than the typical Bow-tie antenna. In addition, the results of verification experiment of Step Frequency Continuous Wave (SFCW) show that the antenna can be applied to the working scenarios of SFCW-GPR.
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Qiua, Dong Dong, Yong Jiang Sun, Hua Song Jin e Jian Cheng Yu. "Directional Pattern Measuring System Research of a TT&C Antenna". Advanced Materials Research 774-776 (settembre 2013): 1518–22. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.1518.
Testo completoAbstract (sommario):
Directional pattern is a clear visual representation form of antenna radiation characteristics. Taking a certain kind of shipborne radar as example, the basic principle of the directional pattern measurement was analyzed, the basic methods and execution scheme were introduced in detail. A directional pattern automatic testing system which was based on Lavbiew was researched on the basis of existed testing techniques, and finally the directional pattern automatic measurement was realized through the use of virtual instrument GPIB and serial interface techniques.
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Azizi, Mussyazwann Azizi Mustafa, Mohammad Nazrin Mohd Noh, Idnin Pasya, Ahmad Ihsan Mohd Yassin e Megat Syahirul Amin Megat Ali. "Pedestrian detection using Doppler radar and LSTM neural network". IAES International Journal of Artificial Intelligence (IJ-AI) 9, n. 3 (1 settembre 2020): 394. http://dx.doi.org/10.11591/ijai.v9.i3.pp394-401.
Testo completoAbstract (sommario):
<span lang="EN-US">Integration of radar systems as primary sensor with deep learning algorithms in driver assist systems is still limited. Its implementation would greatly help in continuous monitoring of visual blind spots from incoming pedestrians. Hence, this study proposes a single-input single-output based Doppler radar and long short-term memory (LSTM) neural network for pedestrian detection. The radar is placed in monostatic configuration at an angle of 45 degree from line of sight. Continuous wave with frequency of 1.9 GHz are continuously transmitted from the antenna. The returning signal from the approaching subjects is characterized by the branching peaks higher than the transmitted frequency. A total of 1108 spectrum traces with Doppler shifts characteristics is acquired from eight volunteers. Another 1108 spectrum traces without Doppler shifts are used for control purposes. The traces are then fed to LSTM neural network for training, validation and testing. Generally, the proposed method was able to detect pedestrian with 88.9% accuracy for training and 87.3% accuracy for testing.</span>
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Ullah, Raza, Sadiq Ullah, Farooq Faisal, Rizwan Ullah, Dong-you Choi, Ashfaq Ahmad e Babar Kamal. "High-Gain Vivaldi Antenna with Wide Bandwidth Characteristics for 5G Mobile and Ku-Band Radar Applications". Electronics 10, n. 6 (12 marzo 2021): 667. http://dx.doi.org/10.3390/electronics10060667.
Testo completoAbstract (sommario):
In this paper, antipodal Vivaldi antenna is designed for 5th generation (5G) mobile communication and Ku-band applications. The proposed designed has three layers. The upper layer consists of eight-element array of split-shaped leaf structures, which is fed by a 1-to-8 power divider network. Middle layer is a substrate made of Rogers 5880. The bottom layer consists of truncated ground and shorter mirror-image split leaf structures. The overall size of the designed antenna is confined significantly to 33.31 × 54.96 × 0.787 (volume in mm3), which is equivalent to 2λo× 3.3λo× 0.05λo (λo is free-space wavelength at 18 GHz). Proposed eight elements antenna is multi-band in nature covering Ku-bands (14.44–20.98 GHz), two millimeter wave (mmW) bands i.e., 24.34–29 GHz and 33–40 GHz, which are candidate frequency bands for 5G communications. The Ku-Band is suitable for radar applications. Proposed eight elements antenna is very efficient and has stable gain for 5G mobile communication and Ku-band applications. The simulation results are experimentally validated by testing the fabricated prototypes of the proposed design.
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Chen, Wei, Guiling Hu, Wenyang Han, Xiaomeng Zhang, Jincheng Wei, Xizhong Xu e Xiangpeng Yan. "Research on the Quality of Asphalt Pavement Construction Based on Nondestructive Testing Technology". Coatings 12, n. 3 (14 marzo 2022): 379. http://dx.doi.org/10.3390/coatings12030379.
Testo completoAbstract (sommario):
In order to better evaluate the construction quality of asphalt pavement, nondestructive testing techniques are used to inspect newly paved asphalt mixture pavement. The proposed system for the evaluation of asphalt pavement construction quality uses three-dimensional ground-penetrating radar (GPR) and a non-nuclear density gauge. The GPR and the non-nuclear density gauge test results were used to establish a dielectric constant–porosity model by fitting. This approach can more accurately determine the dielectric constant selection scheme of the GPR based on the average value of every 10 dielectric constant data points in the length direction of the radar antenna and every three data channels in the width direction. The GPR collected the dielectric constants of the road surface based on the total reflection method and used the average value of the local dielectric constant to evaluate the construction quality of the road. The non-nuclear density gauge used the local porosity to assess the construction quality of the road. It is recommended that the two testing schemes described above be used to evaluate the quality of asphalt pavement construction. They can provide theoretical guidance for future applications in practical processes.
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Campean, Emilia, Tiberiu Pavel Itul, Ionela Tanase e Adrian Pisla. "Workspace Generation for a 2 - DOF Parallel Mechanism Using Neural Networks". Applied Mechanics and Materials 162 (marzo 2012): 121–30. http://dx.doi.org/10.4028/www.scientific.net/amm.162.121.
Testo completoAbstract (sommario):
The main purpose of the paper is to develop a neural network application destined to the workspace generation of a parallel mechanism, as an performant alternative to the workspace representation based on inverse kinematic model. The paper describes both algorithms. The initial testing was made for a parallel mechanism with two degrees of freedom that could be applied for the orientation of different systems like a TV satellite dish antennas, sun trackers, telescopes, cameras, radars etc.
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Urata, Katia, Josaphat Tetuko, Cahya E. Santosa e Tor Viscor. "Development of an L-Band SAR Microsatellite Antenna for Earth Observation". Aerospace 5, n. 4 (17 dicembre 2018): 128. http://dx.doi.org/10.3390/aerospace5040128.
Testo completoAbstract (sommario):
A compact synthetic aperture radar microsatellite antenna operating in the L-band is presented. To reduce size and weight of the small spaceborne SAR, we utilize a lightweight deployable parabolic mesh reflector and operate at low Earth orbital altitudes. The antenna is a wrap-rib center-fed parabolic reflector with dedicated receiving and transmitting feeds. Antenna requirements are: gain better than 30 dBic, center frequency of 1.275 GHz with bandwidth of 28 MHz and circular polarization with axial ratio better than 3 dB. This work describes the development of a compact Circularly Polarized SAR L-band antenna system and the design considerations suitable for small spacecrafts. Simulation of the parabolic reflector and effects of different structural elements to the main radiation pattern were analyzed, which include ribs, struts, feed blockage, and mesh surface. A research model of the parabolic reflector was constructed, and the reflector surface verification was realized using two different approaches, a laser distance meter along ribs and the other using 3D scanning of the reflector surface. RMS errors wree 1.92 mm and 3.86 mm, respectively, both below required 4.55 mm of surface accuracy. Near-field antenna measurements of the deployable reflector mesh antenna was realized for final antenna validation, presenting good agreement with the simulation results. Future work comprises prototyping and testing of the full polarimetric feed assembly.
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Gao, Lan, Chiara Dachena, Kaijun Wu, Alessandro Fedeli, Matteo Pastorino, Andrea Randazzo, Xiaoping Wu e Sébastien Lambot. "Full-Wave Modeling and Inversion of UWB Radar Data for Wave Propagation in Cylindrical Objects". Remote Sensing 13, n. 12 (17 giugno 2021): 2370. http://dx.doi.org/10.3390/rs13122370.
Testo completoAbstract (sommario):
The nondestructive characterization of cylindrical objects is needed in many fields, such as medical diagnostics, tree trunk inspection, or concrete column testing. In this study, the radar equation of Lambot et al. is combined with cylindrical Green’s functions to fully model and invert ultra-wideband (UWB) ground-penetrating radar (GPR) data and retrieve the properties of cylindrical objects. Inversion is carried out using a lookup table (LUT) approach followed by local optimization to ensure retrieval of the global minimum of the objective function. Numerical experiments were conducted to analyze the capabilities of the developed inversion procedure to estimate the radius, permittivity, and conductivity of the cylinders. The full-wave model was validated in laboratory conditions on metallic and plastic pipes of different sizes. The adopted radar system consists of a lightweight vector network analyzer (VNA) connected to a single transmitting and receiving horn antenna. The numerical experiments highlighted the complexity of the inverse problem, mainly originating from the multiple propagation modes within cylindrical objects. The laboratory measurements demonstrated the accuracy of the forward modeling and reconstructions in far-field conditions.
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Zhai, Shao Xiong. "Research on Drive Control Method of Scanning Mechanism of Radar Scatterometer Antenna". Advanced Materials Research 139-141 (ottobre 2010): 1605–11. http://dx.doi.org/10.4028/www.scientific.net/amr.139-141.1605.
Testo completoAbstract (sommario):
A set of drive control system has been developed for the scanning drive system of radar scatterometer antenna, according to the requirements of its scanning motion for speed stability with three-phase AC permanent-magnet synchronous motor(PMSM) driven by sine wave current as the execute component. The system can achieve the aim of controlling motion trace. The system composition, matching design of characteristic parameters such as speed and torque as well as control realization method, are described in this paper and the testing of main system performances such as speed stability is also briefly introduced. It is shown from the simulation and test that the designed system can complete the control of motion track with speed ability of up to 0.5% and can satisfy the given index requirements.
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Delgado, Alfredo, Alexandre Novo e Dirk B. Hays. "Data Acquisition Methodologies Utilizing Ground Penetrating Radar for Cassava (Manihot esculenta Crantz) Root Architecture". Geosciences 9, n. 4 (15 aprile 2019): 171. http://dx.doi.org/10.3390/geosciences9040171.
Testo completoAbstract (sommario):
Cassava (Manihot esculenta Crantz), a root crop utilized as food and industrial starch product, develops and maintains its marketable product sub-surface. Often, however, it is difficult to determine the potentially marketable goods available at any given time due to the sub-surface nature of the product and the inability to non-destructively sample. This dilemma has provided an avenue for application of ground penetrating radar. Relatively available designs of this technology, however, are cumbersome and do not provide the efficiencies for field applications. The objective of this research was to determine the functionality of a two Gigahertz frequency IDS GeoRadar C-Thrue antenna for the detection and parameterization of root architecture to be utilized for estimating marketable product. Cassava roots were buried across three horizontal and two vertical orientations to simulate the multi-directional nature of cassava roots. The antenna has dual polarization which also allowed to testing efficacy of polarization for detecting the varying root orientations. This study found that the C-Thrue system, more specifically, the Vertical transmit and Vertical receive polarization, was the most effective at accurately estimating cassava root length and widths at varying angles that simulate root development in true fields.
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Ivashov, Sergey I., Lorenzo Capineri, Timothy D. Bechtel, Vladimir V. Razevig, Masaharu Inagaki, Nikolay L. Gueorguiev e Ahmet Kizilay. "Design and Applications of Multi-Frequency Holographic Subsurface Radar: Review and Case Histories". Remote Sensing 13, n. 17 (2 settembre 2021): 3487. http://dx.doi.org/10.3390/rs13173487.
Testo completoAbstract (sommario):
Holographic subsurface radar (HSR) is not currently in widespread usage. This is due to a historical perspective in the ground-penetrating radar (GPR) community that the high attenuation of electromagnetic waves in most media of interest and the inability to apply time-varying gain to the continuous-wave (CW) HSR signal preclude sufficient effective penetration depth. While it is true that the fundamental physics of HSR, with its use of a CW signal, does not allow amplification of later (i.e., deeper) arrivals in lossy media (as is possible with impulse subsurface radar (ISR)), HSR has distinct advantages. The most important of these is the ability to do shallow subsurface imaging with a resolution that is not possible with ISR. In addition, the design of an HSR system is simpler than for ISR due to the relatively low-tech transmitting and receiving antennae. This paper provides a review of the main principles of HSR through an optical analogy and describes possible algorithms for radar hologram reconstruction. We also present a review of the history of development of systems and applications of the RASCAN type, which is possibly the only commercially available holographic subsurface radar. Among the subsurface imaging and remote sensing applications considered are humanitarian demining, construction inspection, nondestructive testing of dielectric aerospace materials, surveys of historic architecture and artworks, paleontology, and security screening. Each application is illustrated with relevant data acquired in laboratory and/or field experiments.
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Schwäbig, Christopher, Siying Wang e Sabine Gütgemann. "Development of a millimetre wave based SAR real-time imaging system for three-dimensional non-destructive testing". tm - Technisches Messen 88, n. 7-8 (24 giugno 2021): 488–97. http://dx.doi.org/10.1515/teme-2021-0029.
Testo completoAbstract (sommario):
Abstract The following article describes the development of a millimetre wave based real-time imaging system for three dimensional non-destructive testing of goods. For this purpose a rotating antenna is used which is fed from an FMCW radar. The received measuring data is processed with a SAR algorithm. Due to the fact that a reflexive measurement method is used, the integration of the system into existing systems is simplified. To make the computing power-intensive SAR image processing possible, the complete signal processing chain of the image processing is executed on the graphics card. The article elucidates the concept for calculating the measurement parameters which have to be elaborated for the implementation of the image processing of the whole system.
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Dérobert, Xavier, Vincent Baltazart, Jean-Michel Simonin, Shreedhar Savant Todkar, Christophe Norgeot e Ho-Yan Hui. "GPR Monitoring of Artificial Debonded Pavement Structures throughout Its Life Cycle during Accelerated Pavement Testing". Remote Sensing 13, n. 8 (11 aprile 2021): 1474. http://dx.doi.org/10.3390/rs13081474.
Testo completoAbstract (sommario):
The paper gives an overview of a ground penetrating radar (GPR) experiment to survey debonding areas within pavement structure during accelerated pavement tests (APT) conducted on the university Gustave Eiffel’s fatigue carrousel. Thirteen artificial defect sections composed of three types of defects (Tack-free, Geotextile, and Sand-based) were embedded during the construction phase between the top and the base layers. The data were collected in two stages covering the entire life cycle of the pavement structure using four GPR systems: An air-coupled ultra-wideband GPR (SF-GPR), two wideband 2D ground coupled GPRs (a SIR-4000 with a 1.5 GHz antenna and a 2.6 GHz-StructureScan from GSSI manufacturer), and a wideband 3D GPR (from 3D-radar manufacturer). The first stage of the experiments took place in 2012–2013 and lasted up to 300 K loadings. During this stage, the pavement structure presented no clear degradation. The second stage of experiments was conducted in 2019 and continued until the pavement surface demonstrated a strong degradation, which was observed at 800 K loadings. At the end of the GPR experiments, several trenches were cut at various sections to get the ground truth of the pavement structure. Finally, the GPR data are processed using the conventional amplitude ratio test to study the evolution of the echoes coming from the debonded areas.
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Kauffmann, Jens, Ganesh Rajagopalan, Kazunori Akiyama, Vincent Fish, Colin Lonsdale, Lynn D. Matthews e Thushara Pillai. "The Haystack Telescope as an Astronomical Instrument". Galaxies 11, n. 1 (4 gennaio 2023): 9. http://dx.doi.org/10.3390/galaxies11010009.
Testo completoAbstract (sommario):
The Haystack Telescope is an antenna with a diameter of 37 m and an elevation-dependent surface accuracy of ≤100μm that is capable of millimeter-wave observations. The radome-enclosed instrument serves as a radar sensor for space situational awareness, with about one-third of the time available for research by MIT Haystack Observatory. Ongoing testing with the K-band (18–26 GHz) and W-band receivers (currently 85–93 GHz) is preparing the inclusion of the telescope into the Event Horizon Telescope (EHT) array and the use as a single-dish research telescope. Given its geographic location, the addition of the Haystack Telescope to current and future versions of the EHT array would substantially improve the image quality.
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Widodo, Widodo, Kurnia Anwar Ra’if, Muhammad Aldi Firdaus e Ibnu Thoriq Hidayatullah. "GMODL: An Indonesian MATLAB-based ground-penetrating radar data modeling and processing software". IOP Conference Series: Earth and Environmental Science 1031, n. 1 (1 maggio 2022): 012026. http://dx.doi.org/10.1088/1755-1315/1031/1/012026.
Testo completoAbstract (sommario):
Abstract Ground-penetrating radar (GPR) data modeling and processing is crucial to near-surface geophysics. Its use in geohazard mitigation, construction, shallow hydrocarbon contamination, and other shallow subsurface detection is undeniable due to its high-resolution imaging. GPR software (MATGPR) that we used currently requires access to MATLAB which not everybody can use because of its licensing prices. Thus, we developed this program (GMODL) that uses finite-difference time-domain (FDTD) and split-step Fourier algorithms. To test the software, we created synthetic models. The synthetic model used for the testing is a river model for flood mitigation that consists of a layer of freshwater with ρ = 20 Ωm, k = 81 and μ r = 1 of depth 5 m, two layers of sandstone with ρ = 850 Ωm, k = 2.5 and μ r = 1 of total depth 4 m, and a layer of claystone with ρ = 120 Ωm, k = 11 and μ r = 1 of depth 1 m. The GPR antenna frequency is set to 250 MHz. The testing algorithm of GMODL shows that it can create a synthetic radargram for the river model. The boundary layers are obvious to identify. Also, the freshwater thickness can be determined from the radargram.
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Tatu, Serioja Ovidiu, e Emilia Moldovan. "Millimeter Wave Multi-Port Interferometric Radar Sensors: Evolution of Fabrication and Characterization Technologies". Sensors 20, n. 19 (24 settembre 2020): 5477. http://dx.doi.org/10.3390/s20195477.
Testo completoAbstract (sommario):
Recent advances in millimeter wave technologies, both in component and system design, in line with important size and cost reductions, have opened up new applications in ultra-high-speed wireless communications, radar and imaging sensors. The paper presents the evolution of millimeter wave circuit and modules fabrication and characterization technologies in the past decades. Novel planar low-cost fabrication technologies have been successfully developed in this period. In combination with the standard rectangular wave-guide technology, these offer great opportunities for prototyping and testing of future millimeter wave transceivers or front-ends, which integrate antenna arrays, down-converters, modulators, amplifiers, etc., in a compact fixture. The paper uses, as a suggestive example, the evolution of the multi-port interferometric front-ends implementation from millimeter wave bulky components and systems to miniaturized and high-efficient ones. Circuit and system designs are carefully done to avoid (as much as possible) complicated calibration methods or difficult post-processing of baseband data. This requires an increased effort in design and fabrication, but it allows miniaturization, low-power consumption, while keeping very good overall performances. Useful and straightforward laboratory characterization techniques of circuits and systems are described in detail.
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Darnitskyi, Y., V. Lyashenko, S. Shvets e T. Pavliuk. "ANALYSIS OF PECULIARITIES FOR USE OF MUZZLE VELOCITY MEASUREMENT SYSTEM SL – 520PЕ AND DOPPLER RADAR TRAJECTORY MEASUREMENT SYSTEM MFTR–2100/40 DURING TESTS OF ROCKET AND ARTILLERY ARMAMENT". Наукові праці Державного науково-дослідного інституту випробувань і сертифікації озброєння та військової техніки, n. 12 (5 luglio 2022): 29–40. http://dx.doi.org/10.37701/dndivsovt.12.2022.04.
Testo completoAbstract (sommario):
The article presents a comparative analysis of test results in which the SL–520PЕ muzzle velocity measurement system and the MFTR – 2100/40 Doppler radar system were used. A set of recommendations is proposed, which are aimed at improving the efficiency of the organization and the quality of tests during which the parameters of the initial (muzzle) velocity of the measured objects are determined.
Qualitative testing of a wide range of new and modernized models of rocket and artillery armament largely depends on modern radar measurement systems.
Recently, the Armed Forces of Ukraine (Armed Forces of Ukraine) have been using the SL – 520PЕ muzzle velocity measurement system and the Doppler radar system MFTR – 2100/40 to determine the initial (muzzle) velocity and trajectory measurements of rocket and artillery armament.
The issue of checking the compliance of the parameters of modern models of rocket and artillery armament with the stated specifications is well-timed and is constantly in the focus of attention of the leadership of the Armed Forces of Ukraine.
The above mentioned determines the relevance of scientific research to solve the problem of testing rocket and artillery armament by developing a set of recommendations aimed at improving the efficiency of the organization and quality of tests during which the parameters of the initial (muzzle) velocity of measured objects are determined.
Thus, anticipating the urgency of this issue there was an initiation of research on the feasibility for use of SL–520PЕ muzzle velocity measurement system and the MFTR – 2100/40 Doppler radar system, taking into account their practical employment. Therefore, the author's team considers it appropriate to contemplate certain test methods using the above measurement systems.
The conducted research makes it possible to offer recommendations on setting the options Maximum Velocity, Tracking Time; to determine the magnitude of the minimum value of the start signal level, source of signal, and the optimal value of the angle (Elevation) of the SL–520PЕ antenna for reliable measurement of the initial (muzzle) velocity of artillery shells (mines) during a single shot or a series of shots of the artillery system; determination of the average initial (muzzle) velocity of artillery shells (min) in a series of shots; ensuring the transmission of measured data to the automated fire control system for calculation of ballistic range correction in the process of artillery firing and more efficient testing and certification of artillery weapons offered for procurement to the Armed Forces of Ukraine.
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Wahab, S. W., D. N. Chapman, C. D. F. Rogers, K. Y. Foo, N. Metje, S. W. Nawawi, M. N. Isa e A. Madun. "ASSESSING THE CONDITION OF BURIED PIPE USING GROUND PENETRATING RADAR (GPR)". ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W9 (26 ottobre 2018): 77–81. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w9-77-2018.
Testo completoAbstract (sommario):
<p><strong>Abstract.</strong> The invention of Ground Penetrating Radar (GPR) technology has facilitated the possibility of detecting buried utilities and has been used primarily in civil engineering for detecting structural defects, such as voids and cavities in road pavements, slabs and bridge decks, but has not been used to assess the condition of buried pipes. Pipe deterioration can be defined as pipes where, for example, cracking, differential deflection, missing bricks, collapses, holes, fractures and corrosion exists. Assessing the deterioration of underground pipes is important for service efficiency and asset management. This paper describes a research project that focused on the use of GPR for assessing the condition of buried pipes. The research involved the construction of a suitable GPR test facility in the laboratory to conduct controlled testing in a dry sand. Plastic pipes were chosen for the experiments. A series of laboratory experiments were conducted to determine the validity and effectiveness of standard commercially available GPR technology in assessing the condition of buried utilities with common types of damage. Several types of damage to the plastic pipe were investigated with respect to different GPR antenna frequencies. The GPR surveys were carried out in order to obtain signal signatures from damaged and undamaged pipes buried at 0.5<span class="thinspace"></span>m depth. These surveys were organised on a grid pattern across the surface of the sand in the test facility. The results presented in this paper show that GPR can identify certain types of damage associated with a buried pipe under these controlled laboratory conditions.</p>
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Zou, Lilong, Yan Wang, Iraklis Giannakis, Fabio Tosti, Amir M. Alani e Motoyuki Sato. "Mapping and Assessment of Tree Roots Using Ground Penetrating Radar with Low-Cost GPS". Remote Sensing 12, n. 8 (20 aprile 2020): 1300. http://dx.doi.org/10.3390/rs12081300.
Testo completoAbstract (sommario):
In this paper, we have presented a methodology combining ground penetrating radar (GPR) and a low-cost GPS receiver for three-dimensional detection of tree roots. This research aims to provide an effective and affordable testing tool to assess the root system of a number of trees. For this purpose, a low-cost GPS receiver was used, which recorded the approximate position of each GPR track, collected with a 500 MHz RAMAC shielded antenna. A dedicated post-processing methodology based on the precise position of the satellite data, satellite clock offsets data, and a local reference Global Navigation Satellite System (GNSS) Earth Observation Network System (GEONET) Station close to the survey site was developed. Firstly, the positioning information of local GEONET stations was used to filter out the errors caused by satellite position error, satellite clock offset, and ionosphere. In addition, the advanced Kalman filter was designed to minimise receiver offset and the multipath error, in order to obtain a high precision position of each GPR track. Kirchhoff migration considering near-field effect was used to identify the three-dimensional distribution of the root. In a later stage, a novel processing scheme was used to detect and clearly map the coarse roots of the investigated tree. A successful case study is proposed, which supports the following premise: the current scheme is an affordable and accurate mapping method of the root system architecture.
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Palandro, David, Tim Nedwed, Steve Altobelli, Eiichi Fukushima, Mark Conradi, Nick Sowko e Erik DeMicco. "Oil in and under Ice Detection using Nuclear Magnetic Resonance". International Oil Spill Conference Proceedings 2017, n. 1 (1 maggio 2017): 1877–89. http://dx.doi.org/10.7901/2169-3358-2017.1.1877.
Testo completoAbstract (sommario):
ABSTRACT (2017-387) The application of existing remote sensing sensors and technologies for the detection of oil in and under ice is an ongoing and active research area. Currently, the suite of sensors that have and are being tested include acoustic, radar, optical and fluorosensors. Another technology being tested is Nuclear Magnetic Resonance (NMR) in the earth’s magnetic field. NMR to detect oil in and under ice has undergone extensive testing since 2006 and results to date have been promising. Field tests performed using a prototype 1 × 1 m flat transmitting/receiving antenna coil have differentiated seawater and Crisco® oil, a crude-oil surrogate. Research has been focused on scaling-up the 1 m2 prototype to increase the signal-to-noise ratio (SNR) and allow the sensor to detect oil beneath ice that is up to 1 m thick. The coil currently being tested has a diameter of 6 m in a modified figure-8 pattern. This coil was being tested at Cold Regions Research and Engineering Laboratory (CRREL) in Hanover, New Hampshire, USA. The final phase of feasibility testing was completed in late 2016 with the use of a ruggedized NMR system flown under a helicopter over a pond. The ruggedized NMR system was able to detect a 1.0 cm thick layer of a crude oil surrogate under ~ 110 cm of simulated ice.
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Schouten, Girmi, Wouter Jansen e Jan Steckel. "Simulation of Pulse-Echo Radar for Vehicle Control and SLAM". Sensors 21, n. 2 (13 gennaio 2021): 523. http://dx.doi.org/10.3390/s21020523.
Testo completoAbstract (sommario):
Pulse-echo sensing is the driving principle behind biological echolocation as well as biologically-inspired sonar and radar sensors. In biological echolocation, a single emitter sends a self-generated pulse into the environment which reflects off objects. A fraction of these reflections are captured by two receivers as echoes, from which information about the objects, such as their position in 3D space, can be deduced by means of timing, intensity and spectral analysis. This is opposed to frequency-modulated continuous-wave radar, which analyses the shift in frequency of the returning signal to determine distance, and requires an array of antenna to obtain directional information. In this work, we present a novel simulator which can generate synthetic pulse-echo measurements for a simulated sensor in a virtual environment. The simulation is implemented by replicating the relevant physical processes underlying the pulse-echo sensing modality, while achieving high performance at update rates above 50 Hz. The system is built to perform design space exploration of sensor hardware and software, with the goals of rapid prototyping and preliminary safety testing in mind. We demonstrate the validity of the simulator by replicating real-world experiments from previous work. In the first case, a subsumption architecture vehicle controller is set to navigate an unknown environment using the virtual sensor. We see the same trajectory pattern emerge in the simulated environment rebuilt from the real experiment, as well as similar activation times for the high-priority behaviors (±1.9%), and low-priority behaviors (±0.2%). In a second experiment, the simulated signals are used as input to a biologically-inspired direct simultaneous mapping and localization (SLAM) algorithm. Using only path integration, 83% of the positional errors are larger than 10 m, while for the SLAM algorithm 95% of the errors are smaller than 3.2 m. Additionally, we perform design space exploration using the simulator. By creating a synthetic radiation pattern with increased spatiospectral variance, we are able to reduce the average localization error of the system by 11%. From these results, we conclude that the simulation is sufficiently accurate to be of use in developing vehicle controllers and SLAM algorithms for pulse-echo radar sensors.
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Joo, Jeong-Myeong, Jin-Young Hong, Sang-Jin Shin, Dong-Hyeon Kim e Yisok Oh. "Effects of Antenna Modeling in 2-D FDTD Simulation of an Ultra-Wide Band Radar for Nondestructive Testing of a Concrete Wall". Journal of Korean Institute of Electromagnetic Engineering and Science 24, n. 1 (30 gennaio 2013): 98–105. http://dx.doi.org/10.5515/kjkiees.2013.24.1.98.
Testo completo