| 摘要 |
PROBLEM TO BE SOLVED: To accurately determine an estimated position of a vehicle in even such a condition that GPS is difficult to receive, or the speed of the vehicle is not high. SOLUTION: The navigation system is provided with a current point detecting means 2 that detects a current position of the vehicle, a receiving means 5 that receives radio waves from plural measuring satellites, a vehicle speed detecting means that detects the speed of the vehicle, and a control means 4 that judges whether the vehicle runs on an expressway or an ordinary road on the basis of at least one of the two kinds of information from the measuring satellites and the speed of the vehicle and on the basis of threshold values of the information. The control means includes a threshold varying means that varies the threshold value on the basis of the information about the current position. |
