| 摘要 |
Whether a target GPS signal is successfully captured is determined more accurately than the conventional method. Integrated correlation values are acquired with all code phases by setting a plurality of frequencies at intervals of 1,000 Hz determined based on a code cycle of a GPS signal into a single group (S101). A peak correlation value Peak(i) that is a highest integrated correlation value with each frequency i forming the group is acquired (S102). The peak correlation values Peak(i) of the respective frequencies i are compared to each other, a highest value thereof is set to be a highest peak value Tpeak, and a peak correlation value Peak(i) that is a second highest value is set to be a highest noise value Np. If a ratio Ratio between the highest peak value Tpeak and the highest noise value Np is lower than a threshold Th, it is determined that cross-correlation occurred (S104: YES), and if the ratio Ratio is higher than the threshold Th, the highest peak value Tpeak is determined to be from the target GPS signal (S104: NO), and the GPS signal is captured (S105). |
