Synthetic Aperture Radar Altimeter (SRAL)

SRAL, the Synthetic Aperture Radar Altimeter, is the Sentinel-3 altimeter used for surface topography measurements.^[1][2][3] It flies on Sentinel-3B and represents the Sentinel-3 altimeter design flown across the series.^[1][3] SRAL uses a 13.575 GHz Ku-band channel for range measurements and a 5.41 GHz C-band channel for dual-band ionospheric correction.^[1][2][3] After early commissioning, the instrument operates continuously in SAR delay-Doppler mode except for punctual calibration sequences.^[2] Its measurement scope covers ocean and ice topography, significant wave height, wind speed, inland-water hydrology, sea ice, and land-ice thematic products.^[1][2][3]