Patent ID: 8243136

Claim:
A position identifying system comprising: a radio terminal device carried by a monitoring target; and a sensor device provided with a radio communication unit for communicating by radio with the radio terminal device and an image pickup unit for taking an image of the monitoring target; wherein the radio terminal device comprises: a discrimination information retaining unit for retaining discrimination information specific to the radio terminal device; and a transmission unit for transmitting a detection signal used to detect the position of the radio terminal device along with the discrimination information; and the sensor device comprises: a radio positioning unit for detecting the position of the radio terminal device on the basis of the detection signal containing the discrimination information received by the radio communication unit; an image positioning unit for calculating the position of the monitoring target on the basis of an image taken by the image pickup unit; and an integrated position identifying unit for identifying the position of the monitoring target by linking (i) the position calculated by the image positioning unit and (ii) the position detected by the radio positioning unit and the discrimination information; a correlation unit for correlating the image positioning and radio positioning results of the monitoring target on the basis of a distance between a position calculated by the image positioning unit and a position detected by the radio positioning unit; and a positioning accuracy comparison unit for comparing a positioning accuracy of the image positioning of the monitoring target with a positioning accuracy of the radio positioning thereof, wherein the correlation unit correlates, on the basis of the results of positioning accuracy comparison, the image positioning and radio positioning results of the monitoring target when a position detected by the radio positioning unit exists within a predetermined search area centered on a position calculated by the image positioning unit, when the positioning accuracy of the image positioning is higher, and wherein the correlation unit correlates, on the basis of the results of positioning accuracy comparison, the image positioning and radio positioning results of the monitoring target when a position calculated by the image positioning unit exists within a predetermined search area centered on a position detected by the radio positioning unit, when the positioning accuracy of the radio positioning is higher.