1. A method of suppressing co-channel interference in a satellite communication system, the satellite communication system including a receive antenna having a plurality of antenna elements, each antenna element arranged to provide a respective antenna element signal, the method comprising: digitising each antenna element signal, and processing each digitised antenna element signal to separate received signal components in respective frequency channels present in the element signal; deriving a plurality of beam signals from received signal components in one of the frequency channels; calculating complex weighting values for one or more of said plurality of derived beam signals in said one of the frequency channels; adjusting the one or more of the derived beam signals in accordance with the calculated complex weighting values; and cancelling co-channel interference in at least one derived beam signal in said one of the frequency channels using the one or more adjusted derived beam signals to provide an interference suppressed output signal, wherein calculating complex weighting values comprises using a constant modulus algorithm to determine the weighting values.