σ^{0} is calculated by dividing the power received by the conversion factor X, which is a function of the spacecraft and antenna positions. Because it is computationally expensive to calculate X for each data point the X factor algorithms proposes the use of a pre-computed table of nomimal X values for various scan angles and orbit positions. Unfortunately, the table does not take into account any variations in the orbit, or perturbations to the attitude of the spacecraft.

A perturbation correction algorithm is developed which uses the shift in baseband frequency (Δ*f*) resulting from various perturbations to correct the nominal values of X. Using the combination of the X factor table and the Δ*f* correction, σ^{0} can be retrieved rapidly and accurately. This algorithm will be used to calculate σ^{0} for the upcomming Quikscat and Sea Winds missions.