Patent attributes
An area determination system includes a decision unit, a calculation unit, and a determination unit. The decision unit decides, based on a strength of a radio signal transmitted from a transmitter and received by a receiver, a location of the transmitter. The calculation unit calculates a presence determination value. The presence determination value is based on a number of times that the location of the transmitter is determined to be in a presence determination region during a presence determination time period. The presence determination region corresponds to a target area. The determination unit, when a presence condition is satisfied, determine that the transmitter is in the target area. The presence condition is that a state where the presence determination value is greater than or equal to a presence threshold continues for a presence determination time.