1. A receiving apparatus, comprising: a receiver which respectively receives a plurality of signals that contain known signals continuously within a predetermined period, via a plurality of antennas; a signal generator which respectively generates a plurality of phase rotation signals for synchronizing the phase of the plurality of signals received by said receiver, at least over the period that contains known signals; a phase rotation unit which rotates the phase of the plurality of received signals by the plurality of phase rotation signals generated by said signal generator; a classification unit which selects one of the plurality of signals which are phase-rotated by said phase rotation unit as a representative signal and which classifies the remaining phase rotated signals as signals to be processed; an error detector which respectively detects errors in phase components of the signals to be processed relative to a phase component of the representative signal, after the end of the period that contains the known signals; and an update unit which respectively updates the phase rotated signals corresponding to the signals to be processed, based on the errors in phase components detected by said error detector.