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Towards the Performance Assessment of aMapdrift Autofocus for a P-Band SARMission Implementation
Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
2019 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

In the context of the ESA BIOMASS mission in which for the first time, a P-Band SAR sensor isgoing to be mounted into a spaceborne system. With its penetration capability, it will contributeto the measurement of the biomass and carbon content in the Earth’s forests. An autofocusalgorithm is needed for the correction of phase errors introduced by the changing diffraction indexin the ionosphere. Because of the quickly changing nature of the ionosphere, defocusing has to bemeasured and corrected locally over several sections of a SAR capture.In this thesis, a deep introduction into phase errors is made having in mind that the ionosphereis expected to introduce time varying low frequency errors that can be constructed as a series ofquadratic curves. These quadratic phase errors introduce defocusing that is seen as blur and lossof contrast. An algorithm is proposed and tested for measuring this defocusing, while its strengthsand weaknesses are discussed.The idea of measuring defocusing is to try to recover the temporal phase function that introduceddefocusing in the first place. Here a method to recover this temporal phase function is introduced,and a thorough performance assessment of this retrieval is carried out. The variables involved thequality and reliability of this retrieval are studied one by one.

Place, publisher, year, edition, pages
2019. , p. 67
Keywords [en]
SAR, Autofocus, P-Band, Biomass
National Category
Signal Processing
Identifiers
URN: urn:nbn:se:ltu:diva-76767OAI: oai:DiVA.org:ltu-76767DiVA, id: diva2:1371416
External cooperation
Deutsches Luft- und Raumfahrtzentrum (DLR)
Subject / course
Student thesis, at least 30 credits
Educational program
Space Engineering, master's level (120 credits)
Presentation
2019-11-19, 18:15 (English)
Supervisors
Examiners
Available from: 2019-11-20 Created: 2019-11-19 Last updated: 2019-11-20Bibliographically approved

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2728293031323330 of 78
CiteExportLink to record
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Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
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  • sv-SE
  • Other locale
More languages
Output format
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