Articles de revues : « Satellite interferometry »

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Yang, Yichao, Kohei Yamamoto, Miguel Dovale Álvarez, Daikang Wei, Juan José Esteban Delgado, Vitali Müller, Jianjun Jia et Gerhard Heinzel. « On-Axis Optical Bench for Laser Ranging Instruments in Future Gravity Missions ». Sensors 22, n^o 5 (7 mars 2022) : 2070. http://dx.doi.org/10.3390/s22052070.

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The laser ranging interferometer onboard the Gravity Recovery and Climate Experiment Follow-On mission proved the feasibility of an interferometric sensor for inter-satellite length tracking with sub-nanometer precision, establishing an important milestone for space laser interferometry and the general expectation that future gravity missions will employ heterodyne laser interferometry for satellite-to-satellite ranging. In this paper, we present the design of an on-axis optical bench for next-generation laser ranging which enhances the received optical power and the transmit beam divergence, enabling longer interferometer arms and relaxing the optical power requirement of the laser assembly. All design functionalities and requirements are verified by means of computer simulations. A thermal analysis is carried out to investigate the robustness of the proposed optical bench to the temperature fluctuations found in orbit.

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Noordam, J. E. « European Space Interferometry ». Symposium - International Astronomical Union 166 (1995) : 345. http://dx.doi.org/10.1017/s0074180900228349.

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Optical interferometry is ensconced as an ‘area of future interest’ (a socalled Green Dream) in Horizon 2000, the long-term scientific plan of ESA. Over the years, there have been three large ESA workshops on Space interferometry, where many different concepts and designs were proposed, and several ESA committees have studied the possibilities. These committees were also involved, in an advisory role, in a modest technological research program (TRP) by ESTEC. In 1990, the Space Interferometry Study Team (SIST) recommended building an optical interferometer, consisting of 10-15 small telescopes attached to an 100m inflatable structure, as a scientifically interesting first step. The SIST even produced a workable design. It quickly became clear, however, that such an undertaking would cost much more than an ESA cornerstone mission, and was thus far too ambitious. Simultaneously, another ESA study team (LIST) came to the conclusion that the Moon, contrary to earlier beliefs, does not offer a particularly suitable environment for interferometry. At the Beaulieu workshop in 1992, it was decided to try to achieve cornerstone status for one or two smaller interferometry missions in Space: a 10m UV imaging interferometer, or an interferometric successor to the astrometry satellite Hipparchos. The latter seems to have a good chance at the moment, in the form of the GAIA proposal which has been selected for further study for the new ‘post-Horizon 2000’ program. GAIA may have some limited imaging capability, but a true imaging interferometer in Space will have to wait for a few decades yet.

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Li, Genger. « InSAR terrain mapping error sources based on satellite interferometry ». Open Physics 20, n^o 1 (1 janvier 2022) : 668–79. http://dx.doi.org/10.1515/phys-2022-0064.

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Abstract To improve the accuracy of interferometric synthetic aperture radar (InSAR) topographic mapping, an error source analysis method of InSAR topographic mapping based on satellite interferometry is proposed. According to the basic principle of InSAR altimetry, the preconditions of SAR satellite interferometry are quantitatively analyzed, and the phase error experiment is carried out. The error sources of formation satellite InSAR system are studied. Finally, the error sources affecting the formation satellite InSAR system are systematically analyzed. The experimental results show that this method has good analytical performance, quantitatively evaluates the propagation law of each error, and provides a basic reference for practical application.

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Sun, Yu, Dong et Luo. « ScanSAR Interferometry of the Gaofen-3 Satellite with Unsynchronized Repeat-Pass Images ». Sensors 19, n^o 21 (28 octobre 2019) : 4689. http://dx.doi.org/10.3390/s19214689.

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Gaofen-3 is a Chinese remote sensing satellite with multiple working modes, among which the scanning synthetic aperture radar (ScanSAR) mode is used for wide-swath imaging. synthetic aperture radar (SAR) interferometry in the ScanSAR mode provides the most rapid way to obtain a global digital elevation model (DEM), which can also be realized by Gaofen-3. Gaofen-3 ScanSAR interferometry works in the repeat-pass mode, and image pair non-synchronizations can influence its performance. Non-synchronizations can include differences of burst central times, satellite velocities, and burst durations. Therefore, it is necessary to analyze their influences and improve the interferometric coherence. Meanwhile, interferometric phase compensation and rapid DEM geolocation also need to be considered in interferometric processing. In this paper, interferometric coherence was analyzed in detail, followed by an iterative filtering method, which helped to improve the interferometric performance. Further, a phase compensation method for Gaofen-3 was proposed to compensate for the phase error caused by the unsynchronized azimuth time offset of image pair, and a closed-form solution of DEM geolocation with ground control point (GCP) information was derived. Application of our methods to a pair of Gaofen-3 interferometric images showed that these methods were able to process the images with good accuracy and efficiency. Notably, these analysis and processing methods can also be applied to other SAR satellites in the ScanSAR mode to obtain DEMs with high quality.

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Massonnet, Didier. « Satellite Radar Interferometry ». Scientific American 276, n^o 2 (février 1997) : 46–53. http://dx.doi.org/10.1038/scientificamerican0297-46.

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Nicolás-Álvarez, Jorge, Xavier Carreño-Megias, Estel Ferrer, Miquel Albert-Galí, Judith Rodríguez-Tersa, Albert Aguasca et Antoni Broquetas. « Interferometric Orbit Determination System for Geosynchronous SAR Missions : Experimental Proof of Concept ». Remote Sensing 14, n^o 19 (29 septembre 2022) : 4871. http://dx.doi.org/10.3390/rs14194871.

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Future Geosynchronous Synthetic Aperture Radar (GEOSAR) missions will provide permanent monitoring of continental areas of the planet with revisit times of less than 24 h. Several GEOSAR missions have been studied in the USA, Europe, and China with different applications, including water cycle monitoring and early warning of disasters. GEOSAR missions require unprecedented orbit determination precision in order to form focused Synthetic Aperture Radar (SAR) images from Geosynchronous Orbit (GEO). A precise orbit determination technique based on interferometry is proposed, including a proof of concept based on an experimental interferometer using three antennas separated 10–15 m. They provide continuous orbit observations of present communication satellites operating at GEO as illuminators of opportunity. The relative phases measured between the receivers are used to estimate the satellite position. The experimental results prove the interferometer is able to track GEOSAR satellites based on the transmitted signals. This communication demonstrates the consistency and feasibility of the technique in order to foster further research with longer interferometric baselines that provide observables delivering higher orbital precision.

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Imperatore, Pasquale, Antonio Pepe et Eugenio Sansosti. « High Performance Computing in Satellite SAR Interferometry : A Critical Perspective ». Remote Sensing 13, n^o 23 (24 novembre 2021) : 4756. http://dx.doi.org/10.3390/rs13234756.

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Synthetic aperture radar (SAR) interferometry has rapidly evolved in the last decade and can be considered today as a mature technology, which incorporates computationally intensive and data-intensive tasks. In this paper, a perspective on the state-of-the-art of high performance computing (HPC) methodologies applied to spaceborne SAR interferometry (InSAR) is presented, and the different parallel algorithms for interferometric processing of SAR data are critically discussed at different levels. Emphasis is placed on the key processing steps, which typically occur in the interferometric techniques, categorized according to their computational relevance. Existing implementations of the different InSAR stages using diverse parallel strategies and architectures are examined and their performance discussed. Furthermore, some InSAR computational schemes selected in the literature are analyzed at the level of the entire processing chain, thus emphasizing their potentialities and limitations. Therefore, the survey focuses on the inherent computational approaches enabling large-scale interferometric SAR processing, thus offering insight into some open issues, and outlining future trends in the field.

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Murodov, Suhrob D., et Alexander Yu Chermoshentsev. « METHODOLOGY FOR MONITORING DISPLACEMENTS OF BUILDINGS AND STRUCTURES USING SPACE RADAR SURVEY ». Interexpo GEO-Siberia 6, n^o 2 (8 juillet 2020) : 36–40. http://dx.doi.org/10.33764/2618-981x-2020-6-2-36-40.

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The article is devoted to monitoring the deformation of structures using persistent scattereres interferometry according to the satellite Sentinel-1. The Persistant Scatterers Interferometry technique is described, which is used for processing interferometric pairs of images in SNAP and StaMPS software. As a result, differential interferograms characterizing the change in the height of individual points over a certain period of time are obtained.

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Darbeheshti, Neda, Henry Wegener, Vitali Müller, Majid Naeimi, Gerhard Heinzel et Martin Hewitson. « Instrument data simulations for GRACE Follow-on : observation and noise models ». Earth System Science Data 9, n^o 2 (17 novembre 2017) : 833–48. http://dx.doi.org/10.5194/essd-9-833-2017.

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Abstract. The Gravity Recovery and Climate Experiment (GRACE) mission has yielded data on the Earth's gravity field to monitor temporal changes for more than 15 years. The GRACE twin satellites use microwave ranging with micrometre precision to measure the distance variations between two satellites caused by the Earth's global gravitational field. GRACE Follow-on (GRACE-FO) will be the first satellite mission to use inter-satellite laser interferometry in space. The laser ranging instrument (LRI) will provide two additional measurements compared to the GRACE mission: interferometric inter-satellite ranging with nanometre precision and inter-satellite pointing information. We have designed a set of simulated GRACE-FO data, which include LRI measurements, apart from all other GRACE instrument data needed for the Earth's gravity field recovery. The simulated data files are publicly available via https://doi.org/10.22027/AMDC2 and can be used to derive gravity field solutions like from GRACE data. This paper describes the scientific basis and technical approaches used to simulate the GRACE-FO instrument data.

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Crosetto, M., O. Monserrat, N. Devanthéry, M. Cuevas-González, A. Barra et B. Crippa. « PERSISTENT SCATTERER INTERFEROMETRY USING SENTINEL-1 DATA ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (22 juin 2016) : 835–39. http://dx.doi.org/10.5194/isprs-archives-xli-b7-835-2016.

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This paper is focused on deformation monitoring using a Persistent Scatterer Interferometry technique and the interferometric SAR data acquired by the Sentinel-1 satellite of the European Space Agency. The first part of the paper describes the procedure used to process and analyze Sentinel-1 interferometric SAR data. Two main approaches are described. The first one is a simplified Persistent Scatterer Interferometry approach that exploits two key properties of the Sentinel-1 data: the high coherence of the 12-day interferograms and the reduced orbital tube. The second approach is a full Persistent Scatterer Interferometry approach, where a more sophisticate data treatment is employed. The second part of the paper illustrates the results obtained with the two processing approaches. Two case studies are described. The first one concerns landslide detection and monitoring. In this case, the simplified Persistent Scatterer Interferometry approach was used. The second one regards the deformation monitoring of an urban area. In this case, a full Persistent Scatterer Interferometry approach was used.

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Crosetto, M., O. Monserrat, N. Devanthéry, M. Cuevas-González, A. Barra et B. Crippa. « PERSISTENT SCATTERER INTERFEROMETRY USING SENTINEL-1 DATA ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B7 (22 juin 2016) : 835–39. http://dx.doi.org/10.5194/isprsarchives-xli-b7-835-2016.

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This paper is focused on deformation monitoring using a Persistent Scatterer Interferometry technique and the interferometric SAR data acquired by the Sentinel-1 satellite of the European Space Agency. The first part of the paper describes the procedure used to process and analyze Sentinel-1 interferometric SAR data. Two main approaches are described. The first one is a simplified Persistent Scatterer Interferometry approach that exploits two key properties of the Sentinel-1 data: the high coherence of the 12-day interferograms and the reduced orbital tube. The second approach is a full Persistent Scatterer Interferometry approach, where a more sophisticate data treatment is employed. The second part of the paper illustrates the results obtained with the two processing approaches. Two case studies are described. The first one concerns landslide detection and monitoring. In this case, the simplified Persistent Scatterer Interferometry approach was used. The second one regards the deformation monitoring of an urban area. In this case, a full Persistent Scatterer Interferometry approach was used.

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Tan, Qu Lin, et Chou Xie. « Comparison and Analysis of Permafrost Railway Subgrade Settlement Deformation Monitoring ». Applied Mechanics and Materials 226-228 (novembre 2012) : 1651–54. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.1651.

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Under inclement Qinghai-Tibet plateau environment, monitoring and analysis of railway subgrade deformation in plateau permafrost region has very important engineering significance for stability evaluation and safety management. In the paper, satellite interferometry was applied to measure subgrade deformation in the Beiluhe test site along the Qinghai-Tibet railway with gathered satellite interferometric SAR images. Based on the satellite-interferometry-derived data, the deformation characteristics of six points in different permafrost subgrades (the sliced rock embankment, the crushed rock embankment and railway bridge) along the Qinghai-Tibet railway were analyzed and compared. The analysis results show that settlement is the main behavior of railway subgrade deformation and the deformation amount of railway bridge is less than the sliced or the crushed rock embankment along the Qinghai-Tibet railway in permafrost regions.

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Grzesiak, Karolina, et Wojciech J. Milczarek. « LOS Displacements of Mauna Loa volcano, Hawaii Island, as determined using SBAS-InSAR ». E3S Web of Conferences 55 (2018) : 00006. http://dx.doi.org/10.1051/e3sconf/20185500006.

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This paper presents an overview of the surface displacements retrieval capability of the Differential Synthetic Aperture Radar Interferometry algorithm, using Small Baseline Subset (SBAS) technique, in the context of active volcanic areas. Based on Sentinel-1A images, time series displacements fields of the Mauna Loa volcano area over a 2-year time interval (between 2015 and 2017) were received using batch processing. Based on 35 radar images, a total of 179 interferograms have been calculated. Methodology of Synthetic Aperture Radar (SAR) Sentinel-1 ESA satellite mission data processing with small base (SBAS) interferometric techniques from has been presented. The displacements calculated in the satellite’s Line of Sight (LOS) have been presented graphically on maps and graphs. Application of radar interferometry methods in the case of volcanic surface activity research creates new possibilities in the area of permanent monitoring of this type of areas.

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Chen, Q., T. Li, X. Tang, X. Gao et X. Zhang. « PRELIMINARY GAOFEN-3 INSAR DEM ACCURACY ANALYSIS ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-3 (30 avril 2018) : 173–77. http://dx.doi.org/10.5194/isprs-archives-xlii-3-173-2018.

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GF-3 satellite, the first C band and full-polarization SAR satellite of China with spatial resolution of 1&thinsp;m, was successfully launched in August 2016. We analyze the error sources of GF-3 satellite in this paper, and provide the interferometric calibration model based on range function, Doppler shift equation and interferometric phase function, and interferometric parameters calibrated using the three-dimensional coordinates of ground control points. Then, we conduct the experimental two pairs of images in fine stripmap I mode covering Songshan of Henan Province and Tangshan of Hebei Province, respectively. The DEM data are assessed using SRTM DEM, ICESat-GLAS points, and ground control points database obtained using ZY-3 satellite to validate the accuracy of DEM elevation. The experimental results show that the accuracy of DEM extracted from GF-3 satellite SAR data can meet the requirements of topographic mapping in mountain and alpine regions at the scale of 1&thinsp;:&thinsp;50000 in China. Besides, it proves that GF-3 satellite has the potential of interferometry.

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Rack, Wolfgang, Matt A. King, Oliver J. Marsh, Christian T. Wild et Dana Floricioiu. « Analysis of ice shelf flexure and its InSAR representation in the grounding zone of the southern McMurdo Ice Shelf ». Cryosphere 11, n^o 6 (3 novembre 2017) : 2481–90. http://dx.doi.org/10.5194/tc-11-2481-2017.

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Abstract. We examine tidal flexure in the grounding zone of the McMurdo Ice Shelf, Antarctica, using a combination of TerraSAR-X repeat-pass radar interferometry, a precise digital elevation model, and GPS ground validation data. Satellite and field data were acquired in tandem between October and December 2014. Our GPS data show a horizontal modulation of up to 60 % of the vertical displacement amplitude at tidal periods within a few kilometres of the grounding line. We ascribe the observed oscillatory horizontal motion to varying bending stresses and account for it using a simple elastic beam model. The horizontal surface strain is removed from nine differential interferograms to obtain precise bending curves. They reveal a fixed (as opposed to tidally migrating) grounding-line position and eliminate the possibility of significant upstream bending at this location. The consequence of apparent vertical motion due to uncorrected horizontal strain in interferometric data is a systematic mislocation of the interferometric grounding line by up to the order of one ice thickness, or several hundred metres. While our field site was selected due to its simple boundary conditions and low background velocity, our findings are relevant to other grounding zones studied by satellite interferometry, particularly studies looking at tidally induced velocity changes or interpreting satellite-based flexure profiles.

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Bonaldo, Gianmarco, Amedeo Caprino, Filippo Lorenzoni et Francesca da Porto. « Monitoring Displacements and Damage Detection through Satellite MT-InSAR Techniques : A New Methodology and Application to a Case Study in Rome (Italy) ». Remote Sensing 15, n^o 5 (21 février 2023) : 1177. http://dx.doi.org/10.3390/rs15051177.

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Satellite interferometry has recently developed as a powerful tool for monitoring displacements on structures for structural health monitoring (SHM), as it allows obtaining information on past deformation and performing back analysis on structural behavior. Despite the increasing literature on this subject, the lack of protocols for applying and interpreting interferometric data for structural assessment prevents these techniques from being employed alongside conventional SHM. This paper proposes a methodology for exploiting satellite interferometric data aiming at remotely detecting displacements and buildings’ criticalities at different levels of analysis, i.e., urban scale and single-building scale. Moreover, this research exploits the capability of satellite monitoring for damage diagnosis, comparing the millimeter scale displacements to information derived from on-site inspections. Different data-driven algorithms were applied to detect seasonal and irreversible components of displacements, such as statistical models for damage identification derived from traditional on-site monitoring. Thus, the proposed methodology was applied to a XVI-century case study located in the city center of Rome (Italy), Palazzo Primoli, and two stocks of COSMO-SkyMed (CSK) images processed through the Small BAseline Subset Differential Interferometry (SBAS-DInSAR) technique were used to assess displacements for an eight-year-long (between 2011 and 2019) monitoring period.

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Rott, Helmut. « Advances in interferometric synthetic aperture radar (InSAR) in earth system science ». Progress in Physical Geography : Earth and Environment 33, n^o 6 (12 octobre 2009) : 769–91. http://dx.doi.org/10.1177/0309133309350263.

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During recent years, synthetic aperture radar (SAR) interferometry (InSAR) has become an important tool for precise measurements of the earth’s surface topography and deformation. This paper presents an overview on recent developments in InSAR applications, with emphasis on the use of satellite-borne sensors for applications in geoscience, topographic mapping, natural hazard monitoring and environmental research. InSAR measurement principles are briefly introduced. Recent results on the use of repeat-pass interferometry for mapping seismic and volcanic deformation, monitoring landslides and subsidence, and mapping glacier motion are described. Other InSAR applications introduced in the paper are: topographic mapping, retrieval of biogeophysical parameters on land surfaces, and measurements of water currents. Examples of interferometric products are shown for satellite-borne SAR systems operating at X-band, C-band and L-band radar frequencies. An outlook is provided on upcoming SAR systems which will spur further advances in InSAR techniques and applications.

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Garcia-Mondéjar, Albert, Michele Scagliola, Noel Gourmelen, Jerome Bouffard et Mònica Roca. « Roll Calibration for CryoSat-2 : A Comprehensive Approach ». Remote Sensing 13, n^o 2 (16 janvier 2021) : 302. http://dx.doi.org/10.3390/rs13020302.

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CryoSat-2 is the first satellite mission carrying a high pulse repetition frequency radar altimeter with interferometric capability on board. Across track interferometry allows the angle to the point of closest approach to be determined by combining echoes received by two antennas and knowledge of their orientation. Accurate information of the platform mispointing angles, in particular of the roll, is crucial to determine the angle of arrival in the across-track direction with sufficient accuracy. As a consequence, different methods were designed in the CryoSat-2 calibration plan in order to estimate interferometer performance along with the mission and to assess the roll’s contribution to the accuracy of the angle of arrival. In this paper, we present the comprehensive approach used in the CryoSat-2 Mission to calibrate the roll mispointing angle, combining analysis from external calibration of both man-made targets, i.e., transponder and natural targets. The roll calibration approach for CryoSat-2 is proven to guarantee that the interferometric measurements are exceeding the expected performance.

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Intrieri, Emanuele, William Frodella, Federico Raspini, Federica Bardi et Veronica Tofani. « Using Satellite Interferometry to Infer Landslide Sliding Surface Depth and Geometry ». Remote Sensing 12, n^o 9 (5 mai 2020) : 1462. http://dx.doi.org/10.3390/rs12091462.

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Information regarding the shape and depth of a landslide sliding surface (LSS) is fundamental for the estimation of the volume of the unstable masses, which in turn is of primary importance for the assessment of landslide magnitude and risk scenarios as well as in refining stability analyses. To assess an LSS is not an easy task and is generally time-consuming and expensive. In this work, a method existing in the literature, based on the inclination of movement vectors along a cross-section to estimate the depth and geometry LSSs, is used for the first time while exploiting satellite interferometric data. Given the advent of satellite interferometric data and the related increasing availability of spatially dense and accurate measurements, we test the effectiveness of this method—here named the vector inclination method (VIM)—to four case landslides located in Italy characterized by different types of movement, kinematics and volume. Geotechnical and geophysical information of the LSS is used to validate the method. Our results show that each of the presented cases provides useful insight into the validity of VIM using satellite interferometric data. The main advantages of VIM applied to satellite interferometry are that it enables estimation of the LSS with a theoretical worldwide coverage, as well as with no need for onsite instrumentation or even direct access; however, a good density of measurement points in both ascending and descending geometry is necessary. The combined use of VIM and traditional investigations can provide a more accurate LSS model.

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Crosetto, M., et L. Solari. « DEFORMATION MONITORING USING SATELLITE RADAR INTERFEROMETRY ». ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-3/W2-2020 (29 octobre 2020) : 1–6. http://dx.doi.org/10.5194/isprs-annals-iv-3-w2-2020-1-2020.

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Abstract. The paper is focused on the Persistent Scatterer Interferometry (PSI) technique. First, it addresses the substantial evolution of PSI in the last twenty years. Three main factors are identified: the availability of SAR images, the development of advanced data processing techniques, and the increase of the computation capability. The paper then addresses the PSI deformation monitoring initiatives at regional and national scale. Finally, in the last section, it is described a pan European deformation monitoring service: the European Ground Motion Service (EGMS).

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Bock, Yehuda, et Simon Williams. « Integrated satellite interferometry in Southern California ». Eos, Transactions American Geophysical Union 78, n^o 29 (1997) : 293. http://dx.doi.org/10.1029/97eo00192.

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Qiu, X., C. Ding, B. Lei, B. Han et F. Li. « A NOVEL PROPOSAL OF GAOFEN-3 SATELLITE CONSTELLATION FOR MULTI-APPLICATIONS ». ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2/W7 (13 septembre 2017) : 635–39. http://dx.doi.org/10.5194/isprs-archives-xlii-2-w7-635-2017.

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Gaofen-3 is the first C-band fully polarimetric SAR satellite in China, which is widely used in various fields such as ocean monitoring, disaster reduction and so on. In this paper, a new satellite constellation is proposed based on the orbit of Gaofen-3 satellite. The constellation includes Gaofen-3 and other two duplicates. It is able to do repeat-pass interferometry, repeat-pass differential interferometry, along-track interferometry and stereo measurement. With these abilities, it can generate the earth DEM without ground control points and have better performance in moving target identification and monitoring. The performance and the system requirements are analysed, which provides a good reference for the design of spaceborne SAR constellation.

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Abbot, R. I., R. W. King, Y. Bock et C. C. Counselman. « Earth rotation from radio interferometric tracking of GPS satellites ». Symposium - International Astronomical Union 128 (1988) : 209–13. http://dx.doi.org/10.1017/s0074180900119503.

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Radio-interferometric tracking of the Global Positioning System (GPS) satellites offers a new technique for regular monitoring of variations in the earth's rotation. The observations are sensitive to pole position and length-of-day, at a level of precision which may make this technique competitive with satellite and lunar laser ranging and very long baseline interferometry (VLBI). The present limitations are the number of satellites and tracking stations available and inadequate modeling of non-gravitational forces on the satellites. The potential advantages are rapid turn-around and minimal incremental cost. We have performed a preliminary analysis using six days of observations from a four-station network. Comparison of earth rotation values from our GPS analysis with values obtained by VLBI and laser ranging reveals differences after five days of 0.9 ms in UT1, 0.04″ in x and 0.07″ in y. These differences reflect errors in the GPS determinations due primarily to inadequate modeling of non-gravitational forces.

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Skirmante, K., N. Jekabsons, K. Salmins, V. Bezrukovs et M. Nechaeva. « The Joint SLR (Optical Range) and Radar-VLBI Satellite Observations using VIRAC Radio Telescope RT32, RT16 and SLR Station Riga ». Latvian Journal of Physics and Technical Sciences 57, n^o 1-2 (1 avril 2020) : 62–70. http://dx.doi.org/10.2478/lpts-2020-0008.

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AbstractJoint VLBI and SLR satellite tracking is a novel tracking approach to explore potential applications and to work out common procedures to coordinate observations between astronomical observatories in Latvia. Global Navigation Satellite System (GNSS) satellites equipped with laser retroreflectors have been chosen as test targets because they are accessible by both measuring techniques – satellite laser ranging (SLR) and Very Long Base Interferometry (VLBI).The first Joint SLR and VLBI observations of selected GNSS satellites using three of Latvian large-scale astronomical utilities – VIRAC radio telescopes RT32 and RT16 (Ventspils International Radio Astronomy Centre of Ventspils University of Applied Sciences) with L band receivers and SLR station Riga (Institute of Astronomy of University of Latvia) were obtained in 2016 (NKA16) and 2017 (NKA41 and NKA42).

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Farolfi, Gregorio, Aldo Piombino et Filippo Catani. « Fusion of GNSS and Satellite Radar Interferometry : Determination of 3D Fine-Scale Map of Present-Day Surface Displacements in Italy as Expressions of Geodynamic Processes ». Remote Sensing 11, n^o 4 (15 février 2019) : 394. http://dx.doi.org/10.3390/rs11040394.

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We present a detailed map of ground movement in Italy derived from the combination of the Global Navigation Satellite System (GNSS) and Satellite Synthetic Aperture Radar (SAR) interferometry. These techniques are two of the most used space geodetic techniques to study Earth surface deformation. The above techniques provide displacements with respect to different components of the ground point position; GNSSs use the geocentric International Terrestrial Reference System 1989 (ITRS89), whereas the satellite SAR interferometry components are identified by the Lines of Sight (LOSs) between a satellite and ground points. Moreover, SAR interferometry is a differential technique, and for that reason, displacements have no absolute reference datum. We performed datum alignment of InSAR products using precise velocity fields derived from GNSS permanent stations. The result is a coherent ground velocity field with detailed boundaries of velocity patterns that provide new information about the complex geodynamics involved on the Italian peninsula and about local movements.

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Maltese, Antonino, Claudia Pipitone, Gino Dardanelli, Fulvio Capodici et Jan-Peter Muller. « Toward a Comprehensive Dam Monitoring : On-Site and Remote-Retrieved Forcing Factors and Resulting Displacements (GNSS and PS–InSAR) ». Remote Sensing 13, n^o 8 (16 avril 2021) : 1543. http://dx.doi.org/10.3390/rs13081543.

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Many factors can influence the displacements of a dam, including water level variability and environmental temperatures, in addition to the dam composition. In this work, optical-based classification, thermal diachronic analysis, and a quasi-PS (Persistent Scatter) Interferometric SAR technique have been applied to determine both forcing factors and resulting displacements of the crest of the Castello dam (South Italy) over a one-year time period. The dataset includes Sentinel-1A images acquired in Interferometric Wide swath mode using the Terrain Observation with Progressive Scans SAR (TOPSAR); Landsat 8 Thermal Infrared Sensor (TIRS) thermal images, and Global Navigation Satellite System (GNSS) for interpreting the motion of the top of the dam retrieved via interferometry. Results suggest that it is possible to monitor both dam water level and temperature periodic forcing factors and resulting displacements via a synergistic use of different satellite images.

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Yuwono, B. D., S. Subiyanto, A. S. Pratomo et Najib. « Time Series of Land subsidence rate on Coastal Demak Using GNSS CORS UDIP and DINSAR ». E3S Web of Conferences 94 (2019) : 04004. http://dx.doi.org/10.1051/e3sconf/20199404004.

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Most of the studies land subsidence and impact have been done on the north coastal area of Java, especially Semarang and Demak. This landsubsidence has a very serious impact both in the infra structure, the economy and the environment. Techniques of observing landsubsidence using geodetic methods have been widely practiced. Geodetic technology is undergoing rapid development, especially in GNSS navigation satellite technology as well as satellite radar interferometry. Both have advantages and disadvantages of each. In this study will examine the application of DinSAR interferometric techniques and GNSS technology to predict the rate of land subsidence coastal of Demak regency. This paper also emphasize the role of GNSS and DinSAR application in deformation especially for landsubsidence monitoring.

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Delacourt, Christophe, Pascal Allemand, Etienne Berthier, Daniel Raucoules, Bérangère Casson, Philippe Grandjean, Claude Pambrun et Eric Varel. « Remote-sensing techniques for analysing landslide kinematics : a review ». Bulletin de la Société Géologique de France 178, n^o 2 (1 mars 2007) : 89–100. http://dx.doi.org/10.2113/gssgfbull.178.2.89.

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Abstract Surface displacement field of landslides is a key parameter to access to their geometries and mechanical properties. Surface displacements can be calculated using remote-sensing methods such as interferometry for radar data and image correlation for optical data. These methods have been elaborated this last decade and successfully applied on sensors (radar, cameras, terrestrial 3D laser scanner imaging) either attached to space or aerial platforms such as satellites, planes, and unmanned radio-controlled platforms (drones and helicopters) or settled at fixed positions emplaced in the front of landslides. This paper reviews the techniques of image analysis (interferometry and optical data correlation) to measure displacements and examines the performance of each type of platforms. Examples of applications of these techniques in French South Alps are shown. Depending on the landslide characteristics (exposure conditions, size, velocity) as well as the goal of the study (operational or scientific purpose), one or a combination of several techniques and data (characterized by several resolution, accuracy, covered surface, revisiting time) have to be used. Radar satellite data processed with differential interferometric or PS methods are mainly suitable for scientific purposes due to various application limitations in mountainous area. Optical satellite and aerial images can be used for scientific studies at fairly high resolution but are strongly dependant on atmospheric conditions. Platforms and sensors such as drone, fixed camera, fixed radar and Lidar have the advantage of high adaptability. They can be used to obtain very high resolution and precise 3D data (of centimetric accuracy) suitable for both scientific and operational purposes.

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MATSUOKA, Yoichi, et Seiichiro KAWASE. « Study on Satellite Interferometry for Position Determination ». Transactions of the Society of Instrument and Control Engineers 26, n^o 2 (1990) : 137–44. http://dx.doi.org/10.9746/sicetr1965.26.137.

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Park, Jeong-Won, Jung-Hyun Choi, Yoon-Kyung Lee et Joong-Sun Won. « Intertidal DEM Generation Using Satellite Radar Interferometry ». Korean Journal of Remote Sensing 28, n^o 1 (29 février 2012) : 121–28. http://dx.doi.org/10.7780/kjrs.2012.28.1.121.

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Chang, Ling, Rolf P. B. J. Dollevoet et Ramon F. Hanssen. « Nationwide Railway Monitoring Using Satellite SAR Interferometry ». IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 10, n^o 2 (février 2017) : 596–604. http://dx.doi.org/10.1109/jstars.2016.2584783.

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Sadeghi, Mohammad, Fereidoon Behnia et Hamed Haghshenas. « Positioning of Geostationary Satellite by Radio Interferometry ». IEEE Transactions on Aerospace and Electronic Systems 55, n^o 2 (avril 2019) : 903–17. http://dx.doi.org/10.1109/taes.2018.2866610.

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Vasco, D. W., Charles Wicks, Kenzi Karasaki et Osni Marques. « Geodetic imaging : reservoir monitoring using satellite interferometry ». Geophysical Journal International 149, n^o 3 (26 mai 2002) : 555–71. http://dx.doi.org/10.1046/j.1365-246x.2002.01569.x.

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Grey, William, et Adrian Luckman. « Mapping Urban Extent Using Satellite Radar Interferometry ». Photogrammetric Engineering & ; Remote Sensing 69, n^o 9 (1 septembre 2003) : 957–61. http://dx.doi.org/10.14358/pers.69.9.957.

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Chang, Wen-Yen, Chih-Tien Wang, Chih-Yuan Chu et Jyun-Ru Kao. « Mapping Geo-Hazard by Satellite Radar Interferometry ». Proceedings of the IEEE 100, n^o 10 (octobre 2012) : 2835–50. http://dx.doi.org/10.1109/jproc.2012.2194629.

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Goldstein, Richard M., Howard A. Zebker et Charles L. Werner. « Satellite radar interferometry : Two-dimensional phase unwrapping ». Radio Science 23, n^o 4 (juillet 1988) : 713–20. http://dx.doi.org/10.1029/rs023i004p00713.

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Zieliński, J. B., et E. Butkiewicz. « Satellite orbit determination from radio interferometry data ». Advances in Space Research 5, n^o 2 (janvier 1985) : 193–97. http://dx.doi.org/10.1016/0273-1177(85)90404-1.

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van de Kerkhof, Bas, Victor Pankratius, Ling Chang, Rob van Swol et Ramon F. Hanssen. « Individual Scatterer Model Learning for Satellite Interferometry ». IEEE Transactions on Geoscience and Remote Sensing 58, n^o 2 (février 2020) : 1273–80. http://dx.doi.org/10.1109/tgrs.2019.2945370.

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Fielding, Eric Jameson, Zhen Liu, Oliver L. Stephenson, Minyan Zhong, Cunren Liang, Angelyn Moore, Sang-Ho Yun et Mark Simons. « Surface Deformation Related to the 2019 Mw 7.1 and 6.4 Ridgecrest Earthquakes in California from GPS, SAR Interferometry, and SAR Pixel Offsets ». Seismological Research Letters 91, n^o 4 (4 mars 2020) : 2035–46. http://dx.doi.org/10.1785/0220190302.

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Abstract We analyzed Synthetic Aperture Radar (SAR) images from Copernicus Sentinel-1A and 1B satellites operated by the European Space Agency and the Advanced Land Observation Satellite-2 (ALOS-2) satellite operated by the Japan Aerospace Exploration Agency and Global Navigation Satellite System (GNSS) data from the Network of the Americas for the 4 July 2019 Mw 6.4 and 5 July (local; 6 July UTC) Mw 7.1 Ridgecrest earthquakes. We integrated geodetic measurements for the 3D vector field of coseismic surface deformation for the two events, using SAR data from Sentinel-1 and ALOS-2 satellites. We combined less precise large-scale displacements from SAR images by pixel offset tracking or matching, including the along-track component, with the more precise SAR interferometry (Interferometric Synthetic Aperture Radar [InSAR]) measurements in the radar line of sight (LoS) direction and intermediate-precision along-track InSAR to estimate all three components of the surface displacement for the two events together. We also estimated the coseismic deformation for the two earthquakes from time-series processing of continuous Global Navigation Satellite System data stations in the area. InSAR coherence and coherence change maps the surface disruptions due to fault ruptures reaching the surface. Large slip in the Mw 6.4 earthquake was on a NE-striking fault that intersects with the NW-striking fault that was the main rupture in the Mw 7.1 earthquake. The main fault bifurcates towards the southeast ending 3 km from the Garlock Fault. The Garlock fault had triggered slip of about 20 mm in the radar LoS along a short section directly south of the main rupture. About 3 km northwest of the Mw 7.1 epicenter, the surface fault separates into two strands that form a pull-apart with about 1 m of down-drop. Further northwest is a wide zone of complex deformation.

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Raspini, F., C. Loupasakis, D. Rozos et S. Moretti. « Basin and local scale detection of ground subsidence through persistent scatterer interferometry : The Anthemountas Basin (Northern Greece) case study. » Bulletin of the Geological Society of Greece 47, n^o 3 (21 décembre 2016) : 1510. http://dx.doi.org/10.12681/bgsg.10989.

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In the framework of the Terrafirma Extension project, a study has been established for ground motion detection and mapping in the Anthemountas basin (Central Macedonia). Terrafirma promotes the exploitation of Persistent Scatterer Interferometry (PSI) techniques, a remote sensing technology based on multi-temporal satellite Synthetic Aperture Radar (SAR) imagery. The potential of SAR interferometry has been exploited through the innovative Wide Area Mapping approach, recently implemented by the German Space Agency (DLR) and aimed at measuring land deformation over large areas. Interferometric results from 1995-2001 by ERS1/2 satellites has been analyzed at a basin scale to investigate spatial patterns of land motion in the wider Anthemountas plain, where subsidence phenomena related to intense groundwater extraction is clearly manifested. The WAP results turned out to be a valuable tool for the characterization at local scale of the land subsidence in the runaways area of the Macedonia airport and in the village of Perea, affected in 2005-2006 by a series of tensile ground ruptures due to excessive groundwater withdrawal. Besides the study of the phenomenon, this work confirmed the suitability of PSI techniques to detect and measure surface displacements with millimetre accuracy and also to reconstruct the deformations history of the investigated areas through displacement time series analysis.

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Rahnama, Peyman, Yves J. Rochon, Ian C. McDade, Gordon G. Shepherd, William A. Gault et Alan Scott. « Satellite Measurement of Stratospheric Winds and Ozone Using Doppler Michelson Interferometry. Part I : Instrument Model and Measurement Simulation ». Journal of Atmospheric and Oceanic Technology 23, n^o 6 (1 juin 2006) : 753–69. http://dx.doi.org/10.1175/jtech1880.1.

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Abstract This paper presents an instrument model and observation simulations for the measurement of stratospheric winds and ozone concentration using a satellite instrument employing imaging and the Doppler Michelson interferometery technique. The measurement technique and instrument concept are described. The instrument model and simulations are based on initial design characteristics of the Canadian Stratospheric Wind Interferometer for Transport Studies (SWIFT) satellite instrument. SWIFT employs an imaging array and a field-widened Michelson interferometer. It will measure stratospheric winds and ozone densities using the wind-induced phase shifts of interferograms from atmospheric limb radiance spectra in the vicinity of the vibration–rotation ozone line at 1133.4335 cm−1. The measurement simulation and analysis tools have been developed to assess the SWIFT instrument performance and to evaluate the impact of instrument and measurement characteristics on expected wind and ozone errors. Sample results of the measurement simulation and the related line-of-sight wind error noise levels are presented.

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Vidal-Páez, Paulina, Dominique Derauw, Alfonso Fernandez-Sarría et Miguel Peralta. « Monitoring of Mining Subsidence in a Sector of Central Chile through the Processing of a Time Series of Sentinel 1 Images Using Differential Interferometry Techniques (DInSAR) ». Proceedings 19, n^o 1 (15 juillet 2019) : 10. http://dx.doi.org/10.3390/proceedings2019019010.

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The objective of this work is to monitor the mining subsidence in a mountain range sector of central Chile between 2014 and 2018 through the processing of a time series of Sentinel 1 images using differential interferometry techniques (DInSAR). As a pretest, nine interferometric pairs were considered and processed using SNAP and SNAPHU software. Coherence levels obtained in complex topography sectors were low, due to both temporal and geometrical decorrelation. However, it is proposed that data from the PAZ project (X-band) and the Argentinean SAOCOM satellite (L-band) be used in the future.

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ADLER, RONALD J., HOLGER MUELLER et MARTIN L. PERL. « A TERRESTRIAL SEARCH FOR DARK CONTENTS OF THE VACUUM, SUCH AS DARK ENERGY, USING ATOM INTERFEROMETRY ». International Journal of Modern Physics A 26, n^o 29 (20 novembre 2011) : 4959–79. http://dx.doi.org/10.1142/s0217751x11054814.

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We describe the theory and first experimental work on our concept for searching on earth for the presence of dark contents of the vacuum (DCV) using atom interferometry. Specifically, we have in mind any DCV that has not yet been detected on a laboratory scale, but which might manifest itself as dark energy on the cosmological scale. The experimental method uses two atom interferometers to cancel the effect of earth's gravity and diverse noise sources. It depends upon two assumptions: first, that the DCV possesses some space inhomogeneity in density, and second that it exerts a sufficiently strong nongravitational force on matter. The motion of the apparatus through the DCV should then lead to an irregular variation in the detected matter–wave phase shift. We discuss the nature of this signal and note the problem of distinguishing it from instrumental noise. We also discuss the relation of our experiment to what might be learned by studying the noise in gravitational wave detectors such as LIGO. The paper concludes with a projection that a future search of this nature might be carried out using an atom interferometer in an orbiting satellite. The laboratory apparatus is now being constructed

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Marr, J. M., A. E. E. Rogers, V. L. Fish, F. P. Wilkin, M. B. Arndt, G. Holodak et K. Durkota. « Demonstrating the Principles of Aperture Synthesis with Table- Top Laboratory Exercises ». EPJ Web of Conferences 200 (2019) : 02004. http://dx.doi.org/10.1051/epjconf/201920002004.

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Many undergraduate radio astronomy courses are unable to give a detailed treatment of aperture synthesis due to time constraints and limited math backgrounds of students. We have taken a laboratory-based approach to teaching radio interferometry using a set of college-level, table-top exercises. These are performed with the Very Small Radio Telescope (VSRT), an interferometer developed at the Haystack Observatory using satellite TV electronics as detectors and compact fluorescent light bulbs as microwave signal sources. The hands-on experience provided by the VSRT in these labs allows students to gain a conceptual understanding of radio interferometry and aperture synthesis without the rigorous mathematical background traditionally required. The data are quickly and easily processed using a user-friendly data analysis Java package, VSRTI_Plotter.jar. This software can also be used in the absence of the equipment as an interactive computer activity to demonstrate an interferometer’s responses to assorted surface brightness distributions. The students also gain some familiarity with Fourier transforms and an appreciation for the Fourier relations in interferometry using another Java package, the Tool for Interactive Fourier Transforms (TIFT). We have successfully used these tools in multiple offerings of our radio astronomy course at Union College

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PARCHARIDIS, I. S., et E. LAGIOS. « Deformation in Nisyros volcano (Greece) using differential radar interferometry ». Bulletin of the Geological Society of Greece 34, n^o 4 (1 janvier 2001) : 1587. http://dx.doi.org/10.12681/bgsg.17267.

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Nisyros Volcano located at the southeastern Aegean Sea (Greece) has recently shown (1996-97) a high seismic activity, associated with a significant deformation has determined by DGPS measurements. The determination of the overall deformation of the island was also attempted by Differential Radar Interferometry (DInSAR). The DInSAR analysis has been applied using the ERS-2 satellite data, covering the period 1996-1999. The removal of the interferometric phase related to the topography has been done using an external high resolution DEM. Two areas of the island show a good coherence, the southwestern and the eastern part. Almost two interferometric fringes were respectively recognized and evaluated. These two zones coincide with the main tectonic fractures of the island. The time separation and resolution, which consist important factors, for the extraction of the effective information and the quality of the finally produced differential interferogram, seem however that influence very slight its accuracy. The deformation outlined by the interferogram is compatible with the existing differential GPS observations.

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Lu, Z., D. Mann et J. Freymueller. « Satellite radar interferometry measures deformation at Okmok volcano ». Eos, Transactions American Geophysical Union 79, n^o 39 (1998) : 461. http://dx.doi.org/10.1029/98eo00348.

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Lin-lin, Ge, E. Cheng, D. Polonska, C. Rizos, C. Collins et C. Smith. « Earthquake monitoring in australia using satellite radar interferometry ». Wuhan University Journal of Natural Sciences 8, n^o 2 (juin 2003) : 649–58. http://dx.doi.org/10.1007/bf02899830.

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NI, WEI-TOU. « EMPIRICAL FOUNDATIONS OF THE RELATIVISTIC GRAVITY ». International Journal of Modern Physics D 14, n^o 06 (juin 2005) : 901–21. http://dx.doi.org/10.1142/s0218271805007139.

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In 1859, Le Verrier discovered the mercury perihelion advance anomaly. This anomaly turned out to be the first relativistic-gravity effect observed. During the 141 years to 2000, the precisions of laboratory and space experiments, and astrophysical and cosmological observations on relativistic gravity have been improved by 3 orders of magnitude. In 1999, we envisaged a 3–6 order improvement in the next 30 years in all directions of tests of relativistic gravity. In 2000, the interferometric gravitational wave detectors began their runs to accumulate data. In 2003, the measurement of relativistic Shapiro time-delay of the Cassini spacecraft determined the relativistic-gravity parameter γ to be 1.000021 ± 0.000023 of general relativity — a 1.5-order improvement. In October 2004, Ciufolini and Pavlis reported a measurement of the Lense–Thirring effect on the LAGEOS and LAGEOS2 satellites to be 0.99 ± 0.10 of the value predicted by general relativity. In April 2004, Gravity Probe B (Stanford relativity gyroscope experiment to measure the Lense–Thirring effect to 1%) was launched and has been accumulating science data for more than 170 days now. μSCOPE (MICROSCOPE: MICRO-Satellite à trainée Compensée pour l'Observation du Principle d'Équivalence) is on its way for a 2008 launch to test Galileo equivalence principle to 10-15. LISA Pathfinder (SMART2), the technological demonstrator for the LISA (Laser Interferometer Space Antenna) mission is well on its way for a 2009 launch. STEP (Satellite Test of Equivalence Principle), and ASTROD (Astrodynamical Space Test of Relativity using Optical Devices) are in good planning stage. Various astrophysical tests and cosmological tests of relativistic gravity will reach precision and ultra-precision stages. Clock tests and atomic interferometry tests of relativistic gravity will reach an ever-increasing precision. These will give revived interest and development both in experimental and theoretical aspects of gravity, and may lead to answers to some profound questions of gravity and the cosmos.

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Onrubia, Raul, Daniel Pascual, Jorge Querol, Hyuk Park et Adriano Camps. « The Global Navigation Satellite Systems Reflectometry (GNSS-R) Microwave Interferometric Reflectometer : Hardware, Calibration, and Validation Experiments ». Sensors 19, n^o 5 (27 février 2019) : 1019. http://dx.doi.org/10.3390/s19051019.

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This manuscript describes the Microwave Interferometric Reflectometer (MIR) instrument, a multi-beam dual-band GNSS-Reflectometer with beam-steering capabilities built to assess the performance of a PAssive Reflectrometry and Interferometry System—In Orbit Demonstrator (PARIS-IoD) like instrument and to compare the performance of different GNSS-R techniques and signals. The instrument is capable of tracking up to 4 different GNSS satellites, two at L1/E1 band, and two at L5/E5 band. The calibration procedure of the up- and down-looking arrays is presented, the calibration performance is evaluated, and the results of the validation experiments carried out before the field experiments are shown in this paper.

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Moran, J. M. « Very Long Baseline Interferometry ». Highlights of Astronomy 8 (1989) : 553–54. http://dx.doi.org/10.1017/s1539299600008303.

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The technique of very long baseline interferometry (VLBI) has undergone two decades of steady growth and refinement since its inception in 1967. In the beginning, only crude measurements of visibility on single baselines were possible. Now 18-station arrays have been used to produce images with dynamic ranges exceeding 2000:1; relative motions of cosmic masers have been tracked at the microarcsecond level of accuracy; and angular size measurements have been made with baseline lengths up to 2 two earth diameters with an orbiting satellite as a receiving element.

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