Copernicus Sentinel-6 in action

The Copernicus Sentinel-6 Poseidon-4 dual-frequency (C- and Ku-band) radar altimeter uses an innovative interleaved mode that has improved performance compared to previous satellite altimeter designs. A radar altimeter derives the height of the satellite above Earth by accurately and precisely measuring the time it takes for a transmitted radar pulse to reflect Earth’s surface. The returned echo pulse from the sea surface provides a waveform that is processed to determine sea-surface height (from the radar range), the significant wave height (from the slope of the waveform leading edge) and the surface wind speed from the ocean roughness (determined from the strength of the power returns). Sentinel-6 uses radar pulses that are transmitted and received using a timing arrangement that allows both conventional ‘pulse-limited’ (low-resolution mode) data to be acquired simultaneously with high-resolution ‘delay-Doppler’ measurements. This arrangement allows unfocussed synthetic aperture radar (SAR) data process