| 摘要 |
PROBLEM TO BE SOLVED: To perform positioning having higher reliability by evaluating quantitatively an influence exerted by multipath on the reception state, even when the number of receivable signals is limited to four in positioning using a GPS signal. SOLUTION: When the number of satellites from which the GPS signal can be received is four (step S0), a GPS receiving device selects a value having higher positioning accuracy between an altitude value acquired by performing three-dimensional positioning and an altitude value acquired by a navigation device (step S1-S5), and selects three GPS satellites of different combinations from among the four satellites. When performing four kinds of two-dimensional positioning by adding the selected altitude value (step S8), the device operates a dispersion relative to four kinds of two-dimensional positioning results and evaluates the dispersion (step S9). When the evaluated dispersion exceeds a tolerance ('NO' in step S10), the device issues a command so as to detect the present position by using autonomous navigation performed by the navigation device (step S12). COPYRIGHT: (C)2005,JPO&NCIPI
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