# SAR Interferometer Radar Altimeter (SIRAL)
*component . products*

Ku-band SAR/interferometric radar altimeter on CryoSat-2, optimised for ice-sheet elevation and sea-ice freeboard measurements.

## Specifications
- **manufacturer**: thales-alenia-space
- **deployment context**: orbital
- **entity type**: component
- **last verified date**: 2026-06-16
- **verified by**: agency-doc
- **claim status**: agency-sourced
- **provider**: thales-alenia-space
- **attributes**: {"kind":"component","manufacturer":"thales-alenia-space","deployment_context":"orbital","description":"Ku-band SAR/interferometric radar altimeter on CryoSat-2, optimised for ice-sheet elevation and sea-ice freeboard measurements."}
- **relevance**: in-scope

## Editorial
SIRAL, the SAR Interferometer Radar Altimeter, is the Ku-band radar altimeter flown on CryoSat-2.[^wmo-siral][^aviso-cryosat-siral][^esa-cryosat-handbook] It operates at 13.575 GHz, with WMO listing a 350 MHz bandwidth, and provides CryoSat-2 with a single-frequency radar-altimetry measurement system.[^wmo-siral][^aviso-cryosat-siral][^esa-cryosat-handbook] SIRAL supports low-resolution nadir altimetry, SAR mode, and SAR interferometric mode using two cross-track-aligned antennas.[^wmo-siral][^aviso-cryosat-siral] Those modes let CryoSat-2 measure ice-sheet elevation and sea-ice freeboard while also supporting ocean dynamic topography, significant wave height, and wind speed over sea.[^wmo-siral][^aviso-cryosat-siral] Radar altimetry is demonstrated through SIRAL's CryoSat-2 service record.[^wmo-siral]

## Compositional position
- cryosat-2 (missions) --[mission_payloads]--> SAR Interferometer Radar Altimeter (SIRAL)

## Sources
- [wmo-siral] | WMO OSCAR instrument record: SIRAL | https://space.oscar.wmo.int/instruments/view/siral | tier=agency-doc | accessed=2026-06-16
- [aviso-cryosat-siral] | AVISO+ CryoSat instruments: SIRAL altimeter | https://www.aviso.altimetry.fr/en/missions/current-missions/cryosat/instruments.html | tier=agency-doc | accessed=2026-06-16
- [esa-cryosat-handbook] | CryoSat Product Handbook, ESA Earth Online | https://earth.esa.int/eogateway/documents/20142/37627/CryoSat-Baseline-D-Product-Handbook.pdf | tier=agency-doc | accessed=2026-06-16

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Source: https://eo-atlas.org/products/component/siral
Maintainer: SpectraWorks B.V. (CC-BY 4.0)