Magnetometer with time coded output of measured magnetic fields

US4728888A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

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

Key dates

• Filing date: Jun 10, 1985
• Grant date: Mar 1, 1988
• Expiry date: Jun 10, 2005

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R33/04
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A magnetometer with a time coding is proposed, which serves to measure magnetic fields in the motor vehicle and in particular to measure the direction of the earth field and to determine the driving direction. The magnetometer includes at least one sensor having a horizontally disposed, magnetizable rod-shaped core and a winding disposed on the core. The winding carries an alternating current for generating an auxiliary alternating field, in order to magnetize the core in alternation up to and into saturation. In order to measure the magnetic field detected by the sensor and to generate the auxiliary alternating current, a controlled alternating current source (18) is connected on the one hand to one and the same winding (19), and on the other hand a measurement voltage that can be picked up at this winding (19) is connected to an evaluation circuit (21, 25, 12, 13). The degree of deviation between the positive and negative half-waves of the measurement voltage represents a measure for the magnitude of the magnetic field measured. The magnetometer is intended for use as part of an electronic compass, preferably for navigational purposes in vehicles.