Method of determining an interference-magnetic field in a motor vehicle provided with an electronic compass

US4733179A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Harald Bauer · Ehningen, DE
• Gerhard Hettich · Roßtal, DE

Key dates

• Filing date: Jul 31, 1985
• Grant date: Mar 22, 1988
• Expiry date: Jul 31, 2005

Classification

• Technology area (CPC G): Physics
• CPC primary: G01C17/38
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

To calibrate a electronic compass provided with a magnetometer and being fixedly mounted in a motor vehicle the magnitude, and direction of interference magnetic field must be determined. For this purpose, a constant magnetic field Hg containing an earth's field component He' and the interference field component Hs, is measured by the magnetometer in a first position of the vehicle (Hg1) and then in a second position (Hg2) in which the vehicle is turned by 180.degree.. From the measured constant field magnitudes and directions, (Hg1, Hg2) the interference field component Hs is calculated according to vector equation H.sub.s +1/2 (Hg 1+Hg 2).