Fog of War?

totaly new here, trying to figure out whats possible for a 4X Strategy game…

Is it possible to create a “Fog of War”

so that when one player moves its ships/fleets around, the other does not see it, until there are on the same field or engage each other?

If not, is there a workaround, like giving a fleet an attribute that marks on which possition it is, to be unconvert and verified later?