The AltiKa altimeter records the reflection of K a -band radar pulses from the Earth's surface, with the commonly used waveform product involving the summation of 96 returns to provide average echoes at 40 Hz. Occasionally there are 1-second recordings of the complex individual echoes (IEs), which facilitate the evaluation of on-board processing and offers the potential for new processing strategies. Our investigation of these IEs over the ocean confirms the on-board operations, whilst noting

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... at data quantization limits the accuracy in the thermal noise region. By constructing average waveforms from 32 IEs at a time, and applying an innovative subwaveform retracker, we demonstrate that accurate height and wave height information can be retrieved from very short sections of data. Early exploration of the complex echoes reveals structure in the phase information similar to that noted for Envisat's IEs.