Mgmrs & Utm map pro for andriod. It's a easier than Atak or Civtak you can import kml files and share . I use it for hunting to mark deerstand and set parimeters plus other scouting reconicense. Several scouts can map points of interest and send know file through briar link where someone can coordinate a master map of of all reconeciense. It's not real time coordination but would work one complete map put together you can go off-line and use as map layer.