Abstract: A vehicle navigation apparatus for producing navigation information about a set of road maps, the starting position, current position and destination of a vehicle, a first optimum travel route having the vehicle travel to the destination from the starting position with a shortest driving time interval, and a second optimum travel route having the vehicle travel to the destination from the current position with a shortest driving time interval. The second optimum travel route includes a return travel route having a leading route end junction connected to the first optimum travel route and a trailing end point representative of the current position, and a detour travel route having a detour starting point where the vehicle starts to detour from the first optimum travel route and a detour ending point where the vehicle returns to the first optimum travel route.

Abstract: A heading of a vehicle is detected by correcting an output of a gyro with an offset value stored in an offset memory. A location detecting unit estimates a current location of the vehicle by dead reckoning. When the vehicle continues to travel over a predetermined period of time, the headings of links before and after the current location of the vehicle are read out of a road map memory, and a difference between the two link headings is detected as a first heading change amount. The location detecting unit accumulates outputs of the gyro obtained during a period corresponding to the first heading change amount after the offset correction, and this accumulated value is detected as a second heading change amount. Based on the first and second heading change amounts, a new offset value is calculated. This new offset value is stored in the offset memory.