The Sentinel-6 altimeter, Poseidon-4, transmits half the number of pulses in C-band as compared to previous Jason mission altimeters. As a results, the C-band echoes appear more noisy and current estimations in the operational products show degraded quality especially in low Significant Wave Height conditions. We will discuss and present some options to improve the quality of the C-band estimations. The first option relies on C-band processing only, using a multi-pass retracking approach. On-board echoes are processed and accumulated on ground to generate 1Hz echoes. The second option simply uses Ku-band SWH estimations to constrain C-Band retracking.
We will present the relative performance and the impact on the Sentinel-6 ionosphere correction.