| 摘要 |
PROBLEM TO BE SOLVED: To stably specify a more precise current position. SOLUTION: A portable navigation device 1 detects a current position (X, Y) by GPS satellites C and D to be received and transmits GPS information C and D to an onvehicle navigation device 2. The onboard navigation device 2 also detects a current position (Xs, Ys) from the same GPS satellites C and D. Since the position (Xs, Ys) and the position (X, Y) detected by the portable navigation device 1 are ones detected from the same GPS satellites C and D, almost similar errors occur. Accordingly, the onboard navigation device 2 calculates a difference between current positions (Xb, Yb) and (Xs, Ys) detected highly precisely by GPS satellites A to D and another sensor (α) to be received and transmits this difference as correction information to the portable navigation device 1. In the portable navigation device 1, the current position is corrected by adding (Δx,Δy) to (X, Y). |
