Magnetic compass system for a vehicle
US4862594A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1987 |
| Grant date | Sep 5, 1989 |
| Priority date | — |
| Expiry date | Nov 4, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01C17/26
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A compass and method of operation are disclosed for finding the heading of a vehicle. The heading is found using a compass having a rotor with a compass magnet thereon and means on the rotor defining a reference line in known relation with the polar axis of the magnet. The angular displacement of the rotor is measured between alignment with the direction reference axis and alignment with the local magnetic field. A search coil is used to torque the rotor so that it reaches a reference position in which the reference line thereon is aligned with the direction reference axis. A reference position encoder generates a pulse when alignment is achieved. An angular displacement encoder produces a digital signal which changes with each predetermined increment of rotation of the rotor and which is indicative of the direction of rotation. A microcomputer processes the signals to provide a cumulative count of the increments of rotation. The microcomputer adds a stored magnetic variation value to the cumulative count to provide an indication of true heading. A direction display is adapted to exhibit one direction symbol of a set of symbols for different vehicle headings with each symbol corres…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.