anti-aircraft artillery observation aircraft

artillery observation aircraft

observation point / observation post (OP)

anti-aircraft artillery system

light anti-aircraft artillery

self-propelled AA / air-defense / anti-aircraft artillery

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

artillery observation post

artillery observation unit

field artillery observation battalion

forward artillery observation point

artillery group observation post

artillery groupment observation post

artillery instrumental observation

artillery observation

artillery observation aeroplane

artillery observation helicopter

artillery observation plane

artillery observation post vehicle

artillery observation tank

artillery observation tower

artillery observation vehicle

artillery reconnaissance and observation

forward artillery observation post

mobile artillery observation post

vehicle-mounted artillery observation post

artillery forward observation officer

anti-personnel-anti-material projectile

AV/AT mines (anti-vehicle / anti-tank mines)

observation aircraft (O; obsn acft)

observation aircraft

observation and surveillance aircraft

main artillery (major caliber artillery)