1
general::
noun ADJ. close, constant, regular, round-the-clock, routine | covert | aerial, CCTV/closed-circuit television, electronic, satellite, video | military, police VERB + SURVEILLANCE be under The suspects are under police surveillance. | keep/place/put sb/sth under The country's borders are kept under constant surveillance. | carry out, mount The army carried out covert surveillance of the building for several months. | increase, reduce SURVEILLANCE + NOUN camera, device, equipment | method, operation, system | aircraft | flight | team
Oxford Collocations Dictionary