| 摘要 |
PROBLEM TO BE SOLVED: To enable the position determining arithmetic operation by utilizing radio waves receivable as direct-waves from a satellite with giving priority thereto. SOLUTION: A projection of a solid structure seen from own position is formed using three-dimensional data of the solid structure (step S3), a satellite position calculated in step S4 is superposed on the projection (step S5), whether or not the satellite locates on the solid structure in the projection, i.e., whether or not the solid structure shades own position from the satellite is judged (step S6), and unless the solid structure shades own from the satellite, radio waves receivable from the satellite are recognized as direct-waves and the position determining arithmetic operation is performed by utilizing such radio waves from the satellite with giving priority thereto (step S10). |
