Patent ID: 7969347

Claim:
A position measuring device which measures a position of a signal transmitting device, comprising: a delay profile calculating unit which creates a delay profile representing a correlation between a predetermined code and a signal which is received by a signal receiving device; a received timing calculating unit which determines an incoming wave determination timing which is used to determine a reception of a particular incoming wave transmitted by said signal transmitting device in said signal receiving device and that is a point in time when a value of said delay profile becomes equal to a first threshold, determines a rising timing when said delay profile rises from a noise level and that is a point in time when each value of said delay profile becomes equal to a second threshold which is lower than said first threshold before said incoming wave determination timing, and determines each received timing when said signal receiving device receives said signal as to said incoming wave with reference to said rising timing; and a position calculating unit which calculates each distance between a plurality of said signal receiving devices and said signal transmitting device on the basis of said received timing and measures said position of signal transmitting device from said distances.