field artillery observation battalion

field artillery howitzer battalion

field artillery battalion

glider field artillery battalion

field artillery target acquisition battalion

observation point / observation post (OP)

observation battalion (Obsn Bn)

Siberian Battalion (SB) / Sibir Battalion

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

artillery observation post

artillery observation unit

forward artillery observation point

anti-aircraft artillery observation aircraft

artillery group observation post

artillery groupment observation post

artillery instrumental observation

artillery observation

artillery observation aeroplane

artillery observation aircraft

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

air defense artillery battalion

antiaircraft artillery missile battalion

antitank artillery battalion