surveillance – n. close observation of something, especially a suspected spy or criminal
intercept – v. to stop and take someone or something from one place to another
monitor – v. to observe and check the progress or quality of something
artificial – adj. made or produced by humans rather than occurring naturally
vessel – n. a ship or large boat
maritime – adj. relating to the sea, especially relating to commercial or military activity
routine – adj. done very often; done or happening as part of a normal job
patrol – n. the act of moving through an area to make sure it is safe