Patent ID: 8005172

Claim:
An acquisition apparatus comprising: a first phase-calculating section that includes a first correlator that calculates a first correlation value by performing correlating operation of a reception signal and a reference signal and determines whether or not the first correlation value is equal to or greater than a first threshold; a threshold calculating section that calculates a second threshold by performing averaging operation of the first correlation value and the first threshold when the first correlation value is equal to or greater than the first threshold; and a second phase-calculating section that includes a second correlator that calculates a second correlation value by performing correlating operation of the reception signal and the reference signal on a basis of a phase of the reference signal which realizes the first correlation value equal to or greater than the first threshold, and determines whether or not the second correlation value is equal to or greater than the second threshold, wherein the threshold calculating section calculates the first threshold by performing an averaging operation of the second correlation value and the second threshold value when the second correlation value is smaller than the second threshold.