This カン is 勘 in kanji. "6th sense" is one of its possible translations, but rather than some supernatural ability, it basically refers to a type of "perception" everyone has (people say あの人は勘がいい/悪い but not あの人には勘がある/ない). It broadly refers to instinct, intuition, hunch, and even random guess. Depending on the context, 勘がいい人 may refer to someone who can dodge bullets using their animal-like instincts, someone who can see through another person's lies intuitively, or someone who is good at games like blackjack.
気配の察知 in a context like this refers to perceiving the presence of a (hidden) person/animal. In some fictional works, such as Dragon Ball, 気配 may refer to something akin to "aura" or "qi" that is constantly emitted by lifeforms. But when an ordinary person like me says 誰かの気配がする, it may actually refer to things like subtle breathing sounds or pure hunch.
See also: What is the sense of 気配がする (けはいがする) versus 気がする?