Vehicle navigation apparatus employing node selection, comparison and elimination techniques
US5109344A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 1989 |
| Grant date | Apr 28, 1992 |
| Priority date | — |
| Expiry date | Apr 25, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C21/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A vehicle navigation apparatus which selects possible target nodes stored in memory based on the present position of the vehicle and then eliminates those nodes not possible to reach after comparing the bearing from the present position of the vehicle to each selected node with the present bearing of the vehicle. The navigation apparatus determines that the vehicle is traveling on a road-not-in-memory when the number of possible nodes is reduced to zero. The navigation apparatus repeatedly searches, after each predetermined travel distance, for possible nodes within a progressively widening search circle, the radius of which is related to the distance traveled. When a target is found which is stored in memory the apparatus determines that the vehicle has returned to travel on a road stored in memory.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.