Patent ID: 8762082

Claim:
A movement detection system, comprising: a wireless terminal; a movement detection device connectable via a wireless network to the wireless terminal, wherein the movement detection device transmits detection signals used for detection at a predetermined frequency to the wireless terminal, and the wireless terminal transmits a verification signal in response to each detection signal, and wherein the movement detection device comprises: a detection signal transmission portion that transmits the detection signals; a measurement portion that measures a signal strength of the verification signals transmitted by the wireless terminal, wherein the measured signal strength and the time at which the signal strength is measured are stored as mapped measurement data in a memory device; and a detection portion configured for performing a movement detection process comprising: retrieving the mapped measurement data from the memory device, the mapped measurement data including the measured signal strength and the time; smoothing a curve representing a relationship between the measured signal strength of the verification signals and the time within a time period; applying an approximation function to fit the smoothed curve; determining a difference between the curve and the approximation function; and detecting spatial movement of the wireless terminal based on a result of comparison between the difference and a threshold value.