Apparatus for indicating the direction of a vehicle with abnormal field sensing circuits
US4480226A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 5, 1980 |
| Grant date | Oct 30, 1984 |
| Priority date | — |
| Expiry date | Sep 5, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C17/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A vehicle's heading indicating apparatus includes a direction-finding sensor having a pair of external field sensing windings wound perpendicular to each other, a sensor exciting oscillator circuit, a signal sampling timing circuit, sample-and-hold circuits, comparators, a logic circuit and an indicator circuit. The output of each of the sensor windings is divided into predetermined (N+1) signal levels such that the heading or direction of travel of a vehicle is detected and indicated in accordance with the combination of each two signal levels sensing the heading, and also large disturbance of the earth's magnetic field is sensed such that the just preceding direction of travel obtained is indicated when the earth's magnetic field is excessively low or high. The apparatus further comprises an abnormal field sensing circuit for generating an abnormal field signal upon detecting that the heading sensing signals from the direction-finding sensor have exceeded a predetermined range of levels and an indicator gives an abnormal field indication in response to the abnormal field signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.