| 摘要 |
PROBLEM TO BE SOLVED: To reduce lowering of estimation precision for a position of a measuring point even when interference such as a multipath is generated. SOLUTION: A received electric power calculation means 11 calculates a received electric power level of each reception signal, and a storage means 12 stores the calculated received electric power level. A determination means 13 compares the calculated received electric power level in the present time with a threshold value found from the stored received electric power level in the past, to determine a height of the received electric power level in the present time, as to the each reception signal. A phase difference detecting means 14 detects a phase difference between reception signals from two reception antennas 3, a phase difference selecting means 15 selects the phase difference as to the reception signals having the received electric power level larger than the threshold value, based on a determination result by the determination means 13, and a positioning calculation means 16 estimates the position of the measuring point, based on the selected phase difference. COPYRIGHT: (C)2005,JPO&NCIPI
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