Patent ID: 8022865
Filing Date: 2011-09-20
Classification: G01S

Abstract:
1. A position calculation method that is implemented by a position calculation device that includes a search channel section that searches a positioning satellite, the method comprising: calculating a frequency by using an SNR (Signal to Noise Ratio) that is equal to or greater than a first threshold value as a candidate reception frequency of an acquisition target satellite by causing the search channel section to perform a correlation accumulation process for a first accumulation period within a first search range; determining whether or not the SNR is equal to or greater than a second threshold value that is larger than the first threshold value by causing the search channel section to perform the correlation accumulation process corresponding to the candidate reception frequency for a second accumulation period that is longer than the first accumulation period; calculating a final frequency when it has been determined that the SNR is equal to or greater than the second threshold value by causing the search channel section to perform the correlation accumulation process for a third accumulation period that is longer than the second accumulation period within a second search range that includes the candidate reception frequency and is narrower than the first search range; correcting a search frequency using a difference between an estimated synchronization frequency of the acquisition target satellite and the final frequency; and acquiring the positioning satellite using the search frequency, and calculating a position.