forward artillery observation post

forward observer (FO), forward observation officer; (artillery) observer / spotter

observation point / observation post (OP)

forward observation post

forward observation post observer

forward artillery observation point

artillery forward observation officer

artillery observation post

artillery group observation post

artillery groupment observation post

artillery observation post vehicle

mobile artillery observation post

vehicle-mounted artillery observation post

forward observation

forward observation point

commando forward observation regiment

forward observation unit

command-and-observation post

control observation post

air observation post observer

amount of command of observation post

antiaircraft observation post

battery observation post

cross-observation post

flash-spotting observation post

fort-observation post

groupment observation post

armored observation post

sound ranging observation post

air observation post

air observation post flight

air observation post squadron

command p.-observation post