Patent ID: 7830306

Claim:
A position calculation method comprising: performing correlation calculations on a received signal in a phase direction, the received signal being a signal that may include an indirect wave in addition to a direct wave from a positioning satellite; identifying a phase that corresponds to a peak correlation value among correlation values obtained by the correlation calculations as a tentative peak phase; setting a variance value calculating range in the phase direction based on the tentative peak phase; providing a window having a phase range that is narrower than the variance value calculating range, and moving the window in the phase direction within the variance value calculating range; calculating a variance value of the correlation value within the window at each phase within a moving range of the window; identifying a beginning phase that corresponds to a beginning position to a true peak correlation value when the received signal does not include the indirect wave based on the phase of the window that corresponds to a minimum variance value among the calculated variance values; identifying a true peak phase based on the beginning phase; and calculating a current position using the true peak phase.