2,905 research outputs found
On the Phase Calibration by Multisquint Analysis in TOPSAR and Stripmap Interferometry
No full textThe availability of accurate trajectory information is paramount for the processing and exploitation of synthetic aperture radar (SAR) data. Considering the particular case of spaceborne SARs designed for repeat-pass interferometric applications, errors in the trajectory translate into phase artifacts that affect the interferometric performance. In this paper, we propose a model-based procedure to calibrate the trajectories of spaceborne SAR systems by the multisquint (MS) phase. The technique allows to estimate the along and the derivative of across track geometric errors. The geometric model of the InSAR phase is derived as a function of positioning errors and the MS phase model as derivative of the InSAR phase geometric model, with respect to the squint angle. We perform a sensitivity analysis of the model in order to define which geometric errors can be estimated by the MS phase, justifying the assumption that the MS phase is very poorly affected by the atmospheric phase screen. We particularly concentrate on the TOPSAR acquisition mode, where the phase is very sensitive to geometric errors. We start from the classical two-image case and then consider the extension to the multibaseline case. Experimental results obtained by processing of interferometric pairs acquired by the Sentinel-1A sensor are reported
Multi-Squint Analysis to Separate Geometric and Atmospheric Phase Artifacts in Spaceborne InSAR
No full textThe main issue during phase calibration of spaceborne
SAR system is to properly identify and separate
different contributions to the interferometric phase. In
this paper we suggest to exploit the Multi-Squint (MS)
interferometric phase in order to remove InSAR fringes
due to a linear orbital error, under the key assumption
that the MS phase is very poorly affected by
contributions from the atmospheric delay. Preliminary
results obtained by processing TerraSAR-X stripmap
data appear to confirm the validity of this assumption,
and suggest that MS processing can be operationally
employed for the calibration of spaceborne InSAR datastacks
Rozpor ako východisko, láska ako smer u Simone Weilovej (Contradiction as base, Love as direction in writings of Simone Weil)
No full textArticle is explaining contradiction and love, Simone Weil‘s essential terms of hermeneutics of human Being. It introduces close relation of these terms with her understanding of God as well as with her overall concept of religion. Author also mentions Simone Weil‘s inspirations with philosophical and spiritual concepts of the East
“I beg you to tell me what has become of Djamila”: The Political Mobilization of Simone de Beauvoir’s Readers During the Boupacha Affair
No full textBy Sophia Millman This is a condensed version of a Masters thesis dedicated to the political mobilization of Simone de Beauvoir’s readers. The citations from the letters were translated from French by the author. *** On June 2, 1960, the French government ordered all copies of the daily Algiers edition of Le Monde seized and destroyed to suppress the publication of Simone de Beauvoir’s article “Pour Djamila Boupacha.” Beauvoir, a self-professed “woman of letters”, not “of action[1]”, and one ..
A novel method for noise equivalent sigma nought estimation
No full textIn Synthetic Aperture Radar, Noise Equivalent Sigma Nought (NESZ) is usually verified by measurements over targets with ideally null backscatter, like calm water, or flat surfaces. This condition is quite different from the normal one, in term of quantization, source temperature, ambiguities and received signal energy. We propose a novel method based on interferometry that estimates NESZ in presence of a significant source backscatter. It exploits the principle that noise is the ultimate and unavoidable factor limiting coherence. For each value of backscatter (say in an histogram), a search is made for the target with highest coherence. NESZ is then estimated by fitting the theoretical model of coherence versus signal-to-noise-ratio. The estimate is performed for different range by exploiting narrow strips. The method relies on the existence of some target whose coherence is limited only by thermal noise. Results of processing Sentinel 1A / 1B data over the'Salar de Uyuni' site are here compared with the classical measures over signal-free region
A comparative study of form and theology in the works of Flannery O'Connor and Simone Weil
No full textIn this comparative study of the form and theology of Flannery O'Connor and Simone Weil I interrogate how Weil's philosophical writings and her theology illuminate O'Connor's use of both narrative and non-fictional forms, and her Catholicism. The Introduction analyses how Weil's concept of superposed reading provides a new method of approaching both O'Connor, her writings, and O'Connor
studies, and focuses on how such apparently different women interconnect. Chapter One explores how both Weil and O'Connor attempt to write their theologies on the
souls of their readers yet are each subject to constraints imposed by form. Weil's concept of locating equilibrium between incommensurates is discussed, and her
distinctively philosophical approach to fictions and fictionality is used to investigate O'Connor's notion of prophetic fictions and the writer's role. Chapter Two assesses how both writers revivify Christian paradoxes. Weil's monstrous concept of affiiction, and O'Connor's use of the grotesque genre to jolt secular man into an
awareness of the sacred are scrutinised. Chapter Three studies how both writers consider an encounter between God and man is possible through the action of grace. My Conclusion interrogates how Weil's work can deepen our understanding of O'Connor's writings, and examines how successful O'Connor is at realising a truly
Christian literature. I conclude that despite being a writer of powerful fictions, O'Connor can not be totally successful in her mission as writer-prophet because
ultimately fiction escapes orthodoxy
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