An assistive navigational system for deployment in a facility having a global frame of reference includes: a server including a memory storing: a plurality of anchor definitions each containing (i) an anchor position in the global frame of reference, and (ii) a feature set corresponding to physical characteristics of the facility at the anchor position; and a task definition containing (i) a task position defined relative to the anchor position, and (ii) task overlay data; the server further including a communications interface, and a processor configured to: select one of the anchor definitions for association with the task definition; and transmit the selected anchor definition and the task definition to a mobile computing device, the mobile computing device configured to receive the selected anchor definition and the task definition; the mobile computing device further configured to present the task overlay data on a display.