The following corrections can be computed (depending on the satellites):

  • USO correction (Ultra-Stable Oscillator)
    Correction for drift of onboard oscillators used to generate the internal clock needed for sending radar pulses. The degree of the drift depends on the oscillator frequency.
    Order of magnitude: 1 cm
  • Centre of Gravity (CoG)
    Correction for variations in the satellite’s centre of gravity, due to fuel consumption, solar panel orientation and other factors (the presence of this correction depends on the satellites).
  • Correction tables
    Corrections for instrument and algorithm effects that cannot be modelled. These tables are derived from altimeter simulations (the presence of this correction depends on the satellites).
    Order of magnitude: a few centimetres
  • Applied to Waveforms (before retracking)
    Correction for effects due to filters used to eliminate certain frequencies in the return radar signal.
    Order of magnitude: a few centimetres