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Poseidon-3C Altimeter

Compiled from public sources on 2026-06-16. Not independently verified by Centre National d'Etudes Spatiales.

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Missions → Surface Water and Ocean Topography (SWOT) (operational)

Dual-frequency nadir radar altimeter on SWOT, collecting measurements in the gap between KaRIn swaths.

Poseidon-3C is a nadir, dual-frequency Ku/C radar altimeter in the Poseidon and Jason heritage line, flown on SWOT rather than on Jason-3.^[1]^[2]^[3] The instrument operates around 13.575-13.6 GHz in Ku band and around 5.3 GHz in C band, giving SWOT a conventional nadir-altimetry channel alongside its wide-swath Ka-band interferometer.^[2]^[3]^[4] Its measurements support sea-surface height, significant wave height, wind speed, ionospheric correction, KaRIn calibration, and continuity across the nadir gap between SWOT swaths.^[1]^[4]^[3] Poseidon-3C is operational on SWOT, with WMO listing a 2023-2029 utilisation window and PO.DAAC distributing SWOT nadir-altimeter products from 2022-Dec-16 to present.^[2]^[4]

Where this fits, supply chain

Compositional position

Surface Water and Ocean Topography (SWOT) ——— this payload

Sources

[1]Description and In-Flight Assessment of the POSEIDON-3C Altimeter of the SWOT Missionpeer reviewed2024-11-092026-06-16
[2]WMO OSCAR instrument record: Poseidon-3Cagency doc-2026-06-16
[3]AVISO+ Poseidon-3C instrument pageagency doc-2026-06-16
[4]SWOT Level 2 Nadir Altimeter IGDR Version D, PO.DAACagency doc-2026-06-16

Cite https://eo-atlas.org/products/component/poseidon-3c Markdown twin → Field definitions →