scholarly journals Radar and UAV: georeferencing and airspace surveillance system

2018 ◽  
Vol 11 (2) ◽  
pp. 190-199
Author(s):  
Jonnathan Navarro Roa ◽  
Félix Parca Acevedo ◽  
Giovani Mancilla Gaona
Keyword(s):  
Surveillance System ◽  
Electromagnetic Waves ◽  
Radar System ◽  
Synthetic Aperture ◽  
Electromagnetic Signal ◽  
Radio Detection ◽  
Aerial Vehicle ◽  
The Doppler Effect ◽  
The Waves ◽  
Support Research

A ¨RADAR¨ system, from the English Acronym ¨Radio Detention and Ranging¨. Better known as ¨Radio Detection and Location¨ RDL.  It is a system for detecting and positioning objects through shipping and reflection of electromagnetic waves in terms of the time of issue and the return of the waves and their speed (calculated by the Doppler effect of the electromagnetic signal received).  Meanwhile, an autonomous unmanned vehicle, also known as Unmanned Aerial Vehicle, UAV, which is defined as an aircraft which does not carry a human operator, and uses aerodynamic forces to provide airlift by itself. Therefore, it can fly autonomously or it can be operated by remote control.  This article focuses on the review of experiences where these two technologies are integrated, particularly UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar). This is done in order to support research concerning the combination thereof to be applied in georeferencing humanitarian missions or military missions that require monitoring of airspace. 

Recognition of jet engines via sparse decomposition of ISAR images using a waveguide scattering model

2017 ◽  
Vol 9 (6) ◽  
pp. 1339-1343 ◽  
Author(s):  
Simon Wagner ◽  
Joachim Ender
Keyword(s):  
Electromagnetic Waves ◽  
Radar System ◽  
Synthetic Aperture ◽  
Jet Engines ◽  
Signal Model ◽  
Common Assumption ◽  
Sparse Decomposition ◽  
Imaging Radar ◽  
Scattering Centers ◽  
The Common

Air target recognition is a critical step in the radar processing chain and reliable features are necessary to make a decision. The number and position of jet engines are useful features to perform a pre-classification and give a list of possible targets. To extract these features, a sparse decomposition framework for inverse synthetic aperture radar (ISAR) images is presented. With this framework different components of the target can be detected, if signal models for these parts are available. To use it for the detection of jet engines, a review of a signal model for air intakes, which was developed by Borden, is given. This model is based on the common assumption that the propagation of electromagnetic waves inside jet engines has the same dispersive behavior as inside waveguides. With this model a decomposition of a real ISAR image, measured with the tracking and imaging radar system of Fraunhofer FHR, into point-like scattering centers and jet engines is presented.

scholarly journals Impact of Polarization Distortions on Geometrical Structure Retrieval of Moving Man-Made Targets in ISAR Images

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 373 ◽  
Author(s):  
Qiaoling Liu ◽  
Chen Pang ◽  
Yongzhen Li ◽  
Xuesong Wang
Keyword(s):  
Geometrical Structure ◽  
Phase Error ◽  
Real Data ◽  
Decomposition Methods ◽  
Scattering Matrix ◽  
Radar System ◽  
Synthetic Aperture ◽  
Residual Phase ◽  
Aerial Vehicle ◽  
The Impact

In this paper, the impact of several polarization distortions on geometrical structure retrieval of man-made targets in inverse synthetic aperture radar (ISAR) images is assessed. For polarimetric ISAR, the polarization distortions are usually composed of crosstalk and channel imbalance. For non-stationary targets, a residual phase error exists between two columns of the scattering matrix in the alternate transmission and simultaneous reception (ATSR) mode, especially when the radar frequency is high. These two kinds of distortions have varying influences on different targets, as well as different decomposition methods. Some theoretical derivations and numerical analyses are given to reveal the impact of these distortions on Cameron decomposition. To evaluate the impact of these distortions on geometrical structure retrieval, we use the numerical results and real data of an unmanned aerial vehicle (UAV) called Frontier to perform error analysis of both the decomposition and the retrieved size of the designated structures of the UAV. Some numerical evaluations were conducted from the perspective of system design, and these results can be useful for the practical radar system.

scholarly journals Anomalous Anderson localization behavior in gain-loss balanced non-Hermitian systems

Nanophotonics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 443-452
Author(s):  
Tianshu Jiang ◽  
Anan Fang ◽  
Zhao-Qing Zhang ◽  
Che Ting Chan
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Waves ◽  
Anderson Localization ◽  
Random Media ◽  
Normal Incidence ◽  
Disordered Media ◽  
One Dimensional ◽  
Gain Loss ◽  
The Waves ◽  
Localization Behavior

AbstractIt has been shown recently that the backscattering of wave propagation in one-dimensional disordered media can be entirely suppressed for normal incidence by adding sample-specific gain and loss components to the medium. Here, we study the Anderson localization behaviors of electromagnetic waves in such gain-loss balanced random non-Hermitian systems when the waves are obliquely incident on the random media. We also study the case of normal incidence when the sample-specific gain-loss profile is slightly altered so that the Anderson localization occurs. Our results show that the Anderson localization in the non-Hermitian system behaves differently from random Hermitian systems in which the backscattering is suppressed.

scholarly journals Effects of Motion Compensation Residual Error and Polarization Distortion on UAV-Borne PolInSAR

2021 ◽  
Vol 13 (4) ◽  
pp. 618
Author(s):  
Zexin Lv ◽  
Fangfang Li ◽  
Xiaolan Qiu ◽  
Chibiao Ding
Keyword(s):  
Motion Compensation ◽  
Residual Error ◽  
Synthetic Aperture ◽  
Interferometric Synthetic Aperture Radar ◽  
Practical Application ◽  
Aerial Vehicle ◽  
Application Potential ◽  
Large Motion ◽  
Simulation Results ◽  
Interferometric Sar

Polarimetric Interferometric Synthetic Aperture Radar (PolInSAR) can improve interferometric coherence and phase quality, which has good application potential. With the development of the Mini-SAR system, Unmanned Aerial Vehicle borne (UAV-borne) PolInSAR systems became a reality. However, UAV-borne PolInSAR is easily affected by air currents and other factors, which may cause large motion errors and polarization distortion inevitably exists. However, there are few pieces of research which are about motion compensation residual error (MCRE) and polarization distortion effects on PolInSAR. Though the effects of MCRE on Interferometric SAR (InSAR) and polarization distortion on PolInSAR were studied, respectively, these two parts are independently modeled and analyzed. In this paper, a model that simultaneously considers the effects of these two kinds of errors is proposed, and simulation results are given to validate the model. Then, a quantitative analysis based on a real Quadcopter UAV PolInSAR system is performed according to the model, which is valuable for system design and practical application of the UAV-borne PolInSAR system.

scholarly journals Terrestrial aurora: astrophysical laboratory for anomalous abundances in stellar systems

2014 ◽  
Vol 32 (2) ◽  
pp. 77-82 ◽  
Author(s):  
I. Roth
Keyword(s):  
Solar Flares ◽  
Heavy Ions ◽  
Electromagnetic Waves ◽  
Stellar System ◽  
Decay Product ◽  
Early Solar System ◽  
Physical Processes ◽  
In Situ Observations ◽  
The Waves

Abstract. The unique magnetic structure of the terrestrial aurora as a conduit of information between the ionosphere and magnetosphere can be utilized as a laboratory for physical processes at similar magnetic configurations and applied to various evolutionary phases of the solar (stellar) system. The most spectacular heliospheric abundance enhancement involves the 3He isotope and selective heavy elements in impulsive solar flares. In situ observations of electromagnetic waves on active aurora are extrapolated to flaring corona in an analysis of solar acceleration processes of 3He, the only element that may resonate strongly with the waves, as well as heavy ions with specific charge-to-mass ratios, which may resonate weaker via their higher gyroharmonics. These results are applied to two observed anomalous astrophysical abundances: (1) enhanced abundance of 3He and possibly 13C in the late stellar evolutionary stages of planetary nebulae; and (2) enhanced abundance of the observed fossil element 26Mg in meteorites as a decay product of radioactive 26Al isotope due to interaction with the flare-energized 3He in the early solar system.

scholarly journals EVALUASI HASIL INTEGRASI BERBAGAI KETELITIAN DATA MODEL ELEVASI DIGITAL

GEOMATIKA ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 39
Author(s):  
Fanny Zafira Mukti ◽  
Harintaka Harintaka ◽  
Djurdjani Djurdjani
Keyword(s):  
Synthetic Aperture Radar ◽  
Data Model ◽  
Thermal Emission ◽  
Light Detection And Ranging ◽  
Synthetic Aperture ◽  
Interferometric Synthetic Aperture Radar ◽  
Light Detection ◽  
Aster Gdem ◽  
Radio Detection ◽  
Global Data

<p>Data DEM yang dapat diakses dan digunakan dengan gratis antara lain adalah <em>Shuttle Radar Topography</em> <em>Mission </em>(SRTM) dan <em>Advanced Spaceborne Thermal Emission and Reflection Radiometer </em>Global DEM (ASTER GDEM). Kedua data tersebut mencakup seluruh wilayah di Indonesia, namun ketelitian dan resolusinya rendah, serta masih mengandung kesalahan tinggi. Selain data DEM global, data DEM dapat diperoleh dari hasil perekaman sensor <em>Radio Detection and Ranging </em>(RADAR), <em>Light Detection and Ranging</em> (LIDAR), maupun hasil <em>stereoplotting</em> foto udara dan citra satelit. Masing-masing data tersebut memiliki karakteristik seperti terdapatnya <em>pit</em> dan <em>spire</em>, diskontinuitas pada daerah sambungan dan ketelitian data yang bervariasi. Keberagaman karakteristik pada masing-masing sumber data tersebut dapat menyebabkan inkonsistensi nilai ketinggian antar sumber data. Pada penelitian ini dilakukan pembuatan DEM dengan data DTM Rupa Bumi Indonesia (RBI) skala 1:50.000 dan data DTM <em>Interferometric Synthetic Aperture Radar </em>(IFSAR) di Pulau Kalimantan yang dapat mengatasi inkonsistensi ketinggian tersebut. Metode yang digunakan adalah integrasi dan fusi DEM pada mozaik data-data ketinggian. Pada daerah yang bertampalan, dilakukan dua skenario mozaik yaitu mozaik tanpa bobot dan mozaik berbobot. Uji akurasi vertikal dilakukan dengan menggunakan standar Peraturan Kepala BIG Nomor 15 Tahun 2014 tentang Pedoman Teknis Ketelitian Peta Dasar. Penelitian ini menghasilkan mozaik data DTM yang <em>seamless</em> dan <em>smooth</em> menggunakan metode mozaik berbobot dengan akurasi vertikal sebesar 2,065 meter. Hasil mozaik tanpa bobot masih memiliki beberapa daerah yang tidak <em>seamless</em> dan <em>smooth </em>dengan akurasi vertikal sebesar 2,257 meter. Berdasarkan Tabel Ketelitian Geometri Peta RBI dalam PerKa BIG Nomer 15 Tahun 2014, kedua hasil mozaik tersebut masuk dalam skala 1:10.000.</p><p>Kata kunci: model elevasi digital, mozaik, integrasi, fusi DEM</p>

scholarly journals P-Band InSAR for Geohazard Detection over Forested Terrains: Preliminary Results

2021 ◽  
Vol 13 (22) ◽  
pp. 4575
Author(s):  
Yuankun Xu ◽  
Zhong Lu ◽  
Jin-Woo Kim
Keyword(s):  
Ground Deformation ◽  
Ground Surface ◽  
Radar System ◽  
Synthetic Aperture ◽  
Interferometric Synthetic Aperture Radar ◽  
Forest Canopies ◽  
Jet Propulsion ◽  
Long Wavelength ◽  
Dense Forest ◽  
L Band

Decorrelation of X, C, and L-band InSAR (Interferometric Synthetic Aperture Radar) over densely vegetated regions is a common obstacle for detecting ground deformation beneath forest canopies. Using long-wavelength P-band SAR sensors (wavelength of 69.72 cm), which can penetrate through dense forests and collect relatively consistent signals from ground surface, is one potential solution. Here, we experimented using the NASA JPL (Jet Propulsion Laboratory)’s P-band AirMOSS (Airborne Microwave Observatory of Subcanopy and Subsurface) radar system to collect repeat-pass P-band SAR data over densely vegetated regions in Oregon and California (USA), and generated by far the first P-band InSAR results to test the capability of P-band InSAR for geohazard detection over forested terrains. Our results show that the AirMOSS P-band InSAR could retain coherence two times as high as the L-band satellite ALOS-2 (Advanced Land Observing Satellite-2) data, and was significantly more effective in discovering localized geohazards that were unseen by the ALOS-2 interferograms over densely vegetated areas. Our results suggest that the airborne P-band InSAR could be a revolutionary tool for studying geohazards under dense forest canopies.

scholarly journals The relativity theory of plane waves

1926 ◽  
Vol 111 (757) ◽  
pp. 95-104 ◽  
Keyword(s):  
Gravitational Field ◽  
Electromagnetic Waves ◽  
Small Amplitude ◽  
Plane Waves ◽  
Cumulative Effect ◽  
Relativity Theory ◽  
Transverse Waves ◽  
Propagation Of Light ◽  
Cumulative Change ◽  
The Waves

Weyl has shown that any gravitational wave of small amplitude may be regarded as the result of the superposition of waves of three types, viz.: (i) longitudinal-longitudinal; (ii) longitudinal-transverse; (iii) transverse-transverse. Eddington carried the matter much further by showing that waves of the first two types are spurious; they are “merely sinuosities in the co­ordinate system,” and they disappear on the adoption of an appropriate co-ordinate system. The only physically significant waves are transverse-transverse waves, and these are propagated with the velocity of light. He further considers electromagnetic waves and identifies light with a particular type of transverse-transverse wave. There is, however, a difficulty about the solution as left by Eddington. In its gravitational aspect light is not periodic. The gravitational potentials contain, in addition to periodic terms, an aperiodic term which increases without limit and which seems to indicate that light cannot be propagated indefinitely either in space or time. This is, of course, explained by noting that the propagation of light implies a transfer of energy, and that the consequent change in the distribution of energy will be reflected in a cumulative change in the gravitational field. But, if light cannot be propagated indefinitely, the fact itself is important, whatever be its explana­tion, for the propagation of light over very great distances is one of the primary facts which the relativity theory or any like theory must meet. In endeavouring to throw further light on this question, it seemed desirable to avoid the assumption that the amplitudes of the waves are small; terms neglected on this ground might well have a cumulative effect. All the solu­tions discussed in this paper are exact.

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