Method for pan sharpening a synoptic pair of multispectral images. Each multispectral image contains multiple spectral bands of M band groups, where M is a number of band groups in a range of 1 to M. A panchromatic image associated with the synoptic pair and having a p band is also provided. for each band group m in the range of 1 to M, the method includes the steps of (a) upsampling band group m; (b) pan sharpening band group m using the p band; (c) producing a pan sharpened result for band group m; and repeating steps (a)-(c) to produce pan sharpened results for each band group from 1 to M. Pan sharpened results for band groups 1 to M are fused together to produce a master fused image.