Navigation apparatus for vehicle
US5122961A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Aug 23, 1989 |
| Grant date | Jun 16, 1992 |
| Priority date | — |
| Expiry date | Aug 23, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C21/28
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A navigation apparatus for a vehicle includes a vehicle speed sensor (1-a) for detecting an actual vehicle speed, an odometer (1-b) for detecting a travel distance of the vehicle, a processing unit (5) for calculating a present position from the detection signals from the vehicle speed sensor and the odometer, and a display means for displaying the calculated present position on a map displayed. The actual vehicle speed is compared with an angular velocity of the wheel obtained by the odometer (1-b), and, only when the difference between the actual vehicle speed and the angular velocity of the wheel exceeds a predetermined value, the travel distance is calculated using the actual vehicle speed. The actual vehicle speed sensor (1-a) may include two photosensors. The vehicle speed is operated using the degree of coincidence of the two waveforms. Furthermore, the travel distance is calculated after the vehicle has travelled a fixed distance or for a fixed period of time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.