Coherent change detection between multiple synthetic aperture sonar (SAS) images is reliant on the images being co-registered with sub-pixel accuracy. In this paper we suggest a technique using available navigation data to reconstruct the images onto a common grid. Data obtained using the MUD SAS system is used to demonstrate this method. We show that even with high quality navigation data there is still a misregistration which causes a loss of coherence. Additional data-driven alignment is required in order to use the images for coherent change detection.