1. A method for correcting multislice echo planar imaging (EPI) data for B0 drift effects and N/2 ghosting effects in a magnetic resonance (MR) system, comprising the steps of: (a) generating a plurality of EPI MR image data sets from a volume of a subject to be imaged using a plurality of EPI sequences, wherein: (i) each EPI MR image data set is based on a simultaneous radiofrequency (RF) excitation of a plurality of slices within the volume, and (ii) each EPI sequence comprises an RF excitation pulse and an associated image data readout sequence; (b) generating a plurality of navigator sequences, wherein: (i) each navigator sequence comprises at least three echoes; (ii) at least one navigator sequence is a first type of navigator sequence that is phase encoded and comprises readout gradients that alternate in polarity for each echo; and (iii) at least one navigator sequence is a second type of navigator sequence that is phase encoded and comprises a readout gradient for each echo that is opposite in polarity to the corresponding readout gradient for the first type of navigator sequence; (c) correcting at least one EPI MR image data set for B0 drift effects and N/2 ghosting effects based at least in part on at least one of the first type of navigator sequence and at least one of the second type of navigator sequence; and (d) generating an image of the volume based at least in part on the at least one corrected EPI MR image data set, wherein at least one navigator sequence is a third type of navigator sequence that is not phase encoded, and wherein at least one EPI MR image data set is corrected for B0 drift effects based on at least one of the third type of navigator sequence.