https://cdn.earthdata.nasa.gov/conduit/upload/5182/KeywordsCommunityGuide_Baseline_v1_SIGNED_FINAL.pdf 23.9 2026-05-13T10:52:13.516Z https://gcmd.earthdata.nasa.gov/KeywordViewer/scheme/instruments/2092a1b6-776d-45eb-990a-2838a69c5d86 2020-03-06 Poseidon-4 Radar Altimeter Date=2021-08-04 User Id=sritz Entity=AltLabel Operation=INSERT System Note=insert AltLabel New Value=id: null category: primary text: Poseidon-4 Radar Altimeter language code: en Date=2020-03-06 User Id=mmorahan Entity=BroaderRelation Operation=INSERT User Note=Insert Concept System Note=add broader relation New Value=Poseidon-4 Radar Altimeter [2092a1b6-776d-45eb-990a-2838a69c5d86,559855] - Radar Altimeters [92ddaaca-40b2-4936-bc1a-28cc5743e8b8,544943] Date=2020-03-06 User Id=mmorahan Entity=Definition Operation=INSERT System Note=insert Definition New Value=id: null text: Radar Altimeter (POSEIDON-4): The primary measurement system of SENTINEL-6 (JASON-CS), POSEIDON-4 is a fully redundant normal incidence Ku and C band pulse-width limited radar altimeter with the capability of acquiring phase coherent measurements of a surface allowing synthetic-aperture processing to improve along-track sampling and reducing range and Significant Wave Height (SWH) noise as a function of SWH. Overall performances will be improved with respect to other ocean topography altimeter missions by means of improvements in the design and in an optiminsed pulse timing pattern. The main characteristics of the POSEIDON-4 (SENTINEL-6 Ku/C radar altimeter) are: Radar measurement modes: Interleaved mode (simultaneous LRM and SAR, plus reduced-data-rate-SAR RMC Ku-band central frequency of 13.575 GHz, total bandwidth of 320 MHz C-band secondary frequency, used for ionosphere corrections, central frequency of 5.41 GHz, total bandwidth of 320 MHz Tracking modes: closed and open-loop Pulse repetition frequency: approximately 9 kHz (variable from 9.076 to 9.280 kHz) With the current POSEIDON-4 design theoretical performances have been assessed which demonstrates that SENTINEL-6 will improve on its required performances for both LRM and SAR processing. language code: en Radar Altimeter (POSEIDON-4): The primary measurement system of SENTINEL-6 (JASON-CS), POSEIDON-4 is a fully redundant normal incidence Ku and C band pulse-width limited radar altimeter with the capability of acquiring phase coherent measurements of a surface allowing synthetic-aperture processing to improve along-track sampling and reducing range and Significant Wave Height (SWH) noise as a function of SWH.Overall performances will be improved with respect to other ocean topography altimeter missions by means of improvements in the design and in an optiminsed pulse timing pattern. The main characteristics of the POSEIDON-4 (SENTINEL-6 Ku/C radar altimeter) are: Radar measurement modes: Interleaved mode (simultaneous LRM and SAR, plus reduced-data-rate-SAR RMCKu-band central frequency of 13.575 GHz, total bandwidth of 320 MHzC-band secondary frequency, used for ionosphere corrections, central frequency of 5.41 GHz, total bandwidth of 320 MHzTracking modes: closed and open-loopPulse repetition frequency: approximately 9 kHz (variable from 9.076 to 9.280 kHz)With the current POSEIDON-4 design theoretical performances have been assessed which demonstrates that SENTINEL-6 will improve on its required performances for both LRM and SAR processing. 2021-08-04 17:02:19.0