Navigation apparatus and program storage medium

• US 20090082953A1
• Filed: 09/23/2008
• Published: 03/26/2009
• Est. Priority Date: 09/25/2007
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Shimizu, Yasuhiro
• Granted Patent: US 8,150,616 B2
• Time in Patent Office: Days
• US Class Current: 701/205
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments

Abstract

A navigation apparatus mounted in a subject vehicle designates an inference destination point based on historical data and calculates a reference route to the inference destination point. If the subject vehicle deviates from the reference route before arriving at the inference destination point, the navigation apparatus records a shift route until the subject vehicle returns to the reference route. When the subject vehicle returns to the reference route, the shift route from a deviation point to a return point is recorded as a difference route.

Claims

1. A navigation apparatus comprising:

a navigation means for calculating a guidance route and navigating along the calculated guidance route;

a destination inference means for reading position information resulting from an act of a user taking place before an immediately preceding start-up and designating an inference destination point based on the read position information without receiving a direct and unique designation for a destination point by the user;

a reference route calculation means for calculating a reference route to reach the designated inference destination point;

a deviation detection means for detecting a deviation of a present position from the calculated reference route;

a return detection means for detecting a return of the present position to the reference route after the deviation is detected; and

a record means for recording as a difference route a shift route from a deviation point where the deviation is detected to a return point where the return is detected,

wherein in calculating a guidance, route, the navigation means is configured to prioritize the difference route over another route, as a part of a guidance route including a segment from the deviation point to the return point.

2. The navigation apparatus according to claim 1, wherein

the destination inference means is configured to designate the inference destination point after the start-up without receiving an operation by the user.

3. The navigation apparatus according to claim 1, further comprising:

a record cancellation means for canceling the recording of the shift route after the deviation is detected when a predetermined cancellation condition is satisfied before the return is detected.

4. The navigation apparatus according to claim 3, wherein

the cancellation condition is satisfied when a main power supply is not turned ON within a reference time period after being turned OFF.

5. The navigation apparatus according to claim 4, wherein

as a time period from when the main power supply is turned ON to when the main power supply is turned OFF is longer, the reference time period is longer.

6. The navigation apparatus according to claim 3, wherein

the cancellation condition is satisfied after the deviation is detected when a reference number of times is reached by a number of times of being turned OFF of the main power supply before the return is detected.

7. The navigation apparatus according to claim 6, wherein

as a distance from the deviation point to the return point is longer, the reference number of times is greater.

8. The navigation apparatus according to claim 1, wherein

the destination inference means is configured to designate more than one inference destination point, and

the reference route calculation means is configured to calculate reference routes so as to correspond to the more than one inference destination point.

9. The navigation apparatus according to claim 8, wherein

when a deviation is detected based on one of the more than one reference route, the return detection means is configured to thereafter detect a return to the one of the more than one reference route.

10. A program storage medium containing instructions readable and executable by a computer, the instructions for causing the computer to function as all the means of the navigation apparatus according to claim 1.