| 摘要 |
PROBLEM TO BE SOLVED: To appropriately determine according to receiving environment which one out of increase in positioning accuracy and reduction in TTFF should be given priority to, on the occasion of outputting first positioning results. SOLUTION: In the first positioning, a positioning process that calculates the present position based on acquired GPS satellite signals (step A3) is performed a plurality of times repeatedly. A number of times that the difference (position difference)ΔP between the calculated present located position and the preceding located position is successively equal to or less than a predetermined value is counted using a position counter, and a number of times that the difference (time difference)ΔT between the present time error and the preceding time error is successively equal to or less than a predetermined value is counted using a time counter each time the positioning process is performed (step A5). A position threshold value and a time threshold value are determined by changing a reference threshold value by an amount corresponding to an APR average value (step A7). When the position count value has reached the position threshold value (step A9: YES) and the time count value has reached the time threshold value (step A11: YES), the present located position is determined to be the first located position and output (step A13). COPYRIGHT: (C)2009,JPO&INPIT |
