Earth Observation with GNSS Reflections E-GEM – GNSS-R Earth Monitoring D4.1 State of the Art Description Document 13 - Jan 15 Prepared by: Estel Cardellach (ICE-CSIC/IEEC), Sections 1, 2, 3, 4, 5 Tiago Peres and Rita Castro, Nuno Catarino (DEIMOS), Section 2.3 Nilda Sanchez (USAL), Maria Piles, Adriano Camps (UPC) section 5.4.4 Leila Guerriero (TOV-DICII), review of Sections 5.4 and 5.5 Nazzareno Pierdicca (DIET), review of Sections 5.4 and 5.5 Jorge Bandeiras (DEIMOS), document formatting andApproved review by: E-GEM Steering Committee REF: E- GEM- CSC- TEC- TNO01 VER: 35 Earth Observation with GNSS Reflections Table of Contents 1 Introduction ................................................................................................................................................................. 6 1.1 Basics of GNSS-RefLectometry ............................................................................................................................. 6 2 ConsteLLations and SignaLs ............................................................................................................................................ 9 2.1 Systems and ConstelLations ................................................................................................................................ 9 2.2 Spatial Coverage ................................................................................................................................................ 10 2.3 GNSS SignaLs ...................................................................................................................................................... 11 2.3.1 Definition .................................................................................................................................................. 11 2.3.2 Signals Description .................................................................................................................................... 12 3 GNSS-R Observables and ModeLLing .......................................................................................................................... 16 3.1 Basic GNSS-R Observables ................................................................................................................................. 16 3.2 Electromagnetic Scattering ModeLs ................................................................................................................... 18 4 Receiver-level Data Acquisition ................................................................................................................................. 21 4.1 Existing GNSS-R Receivers ................................................................................................................................. 24 5 Scientific AppLications and Requirements ................................................................................................................. 27 5.1 Ocean: ALtimetry ............................................................................................................................................... 28 5.1.1 GNSS-R Status on Altimetric Applications and RetrievaL Algorithms ........................................................ 29 5.1.2 GNSS-R Altimetric Missions ...................................................................................................................... 33 5.1.3 Other ReLated Techniques ........................................................................................................................ 33 5.1.4 E-GEM AppLicabiLity .................................................................................................................................. 33 5.2 Ocean: Surface Roughness, Wind and TropicaL Storms/CycLones ..................................................................... 34 5.2.1 GNSS-R Status on Ocean Scatterometric Applications and RetrievaL Algorithms ..................................... 38 5.2.2 GNSS-R Scatterometric Missions .............................................................................................................. 41 5.2.3 Other ReLated Techniques ........................................................................................................................ 41 5.2.4 E-GEM AppLicabiLity .................................................................................................................................. 42 E-GEM-CSC-TEC-TNO01 13–Jan-2015 www.e-gem.eu Version: 35 E-GEM PROJECT REFERENCE: 607126 2 of 88 Earth Observation with GNSS Reflections 5.3 Ocean: SaLinity ................................................................................................................................................... 42 5.3.1 GNSS-R Status on Sea Surface SaLinity Applications and RetrievaL Algorithms ......................................... 43 5.3.2 GNSS-R Sea Surface SaLinity Missions ....................................................................................................... 43 5.3.3 Other ReLated Techniques ........................................................................................................................ 43 5.3.4 E-GEM AppLicabiLity .................................................................................................................................. 44 5.4 Land: SoiL Moisture ............................................................................................................................................ 44 5.4.1 GNSS-R Status on SoiL Moisture Applications and RetrievaL Algorithms .................................................. 45 5.4.2 GNSS-R SoiL-Moisture Missions ................................................................................................................. 46 5.4.3 Other ReLated Techniques ........................................................................................................................ 47 5.4.4 E-GEM AppLicabiLity .................................................................................................................................. 48 5.5 Land: Vegetation and Biomass .......................................................................................................................... 50 5.5.1 GNSS-R Status on Vegetation Applications and RetrievaL Algorithms ...................................................... 51 5.5.2 GNSS-R VEGETATION Missions ................................................................................................................. 52 5.5.3 Other ReLated Techniques ........................................................................................................................ 52 5.5.4 E-EGM AppLicabLiLity .................................................................................................................................. 53 5.6 HydroLogy: InLand-water Bodies ........................................................................................................................ 54 5.7 Cryosphere: Snow .............................................................................................................................................. 54 5.7.1 GNSS-R Status on Snow Applications and RetrievaL Algorithms ............................................................... 55 5.7.2 GNSS-R Snow Missions: ............................................................................................................................ 56 5.7.3 Other ReLated Techniques: ....................................................................................................................... 56 5.7.4 E-GEM ApLicabiLLity .................................................................................................................................... 57 5.8 Cryosphere: Sea Ice ........................................................................................................................................... 57 5.8.1 GNSS-R Status on Sea-Ice Applications and Retrieval Algorithms: ........................................................... 58 5.8.2 GNSS-R Sea-Ice Missions ........................................................................................................................... 60 5.8.3 Other ReLated Techniques ........................................................................................................................ 60 5.8.4 E-GEM AppLicabiLity .................................................................................................................................. 61 E-GEM-CSC-TEC-TNO01 13–Jan-2015 www.e-gem.eu Version: 35 E-GEM PROJECT REFERENCE: 607126 3 of 88 Earth Observation with GNSS Reflections 5.9 Cryosphere: GLaciers .......................................................................................................................................... 62 5.10 Atmosphere ....................................................................................................................................................... 62 5.11 CiviLian Applications: Ship Detection ................................................................................................................. 63 5.12 CiviLian Applications: Buried MetaLLic Bodies .................................................................................................... 64 6 REFERENCES .............................................................................................................................................................. 65 7 ACRONYMS 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