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.