Magnetic field detector for detecting earth's magnetic field

• US 5,187,437 A
• Filed: 01/04/1991
• Issued: 02/16/1993
• Est. Priority Date: 01/04/1990
• Status: Expired due to Fees

• Current Assignee: Instrumentverken AB
• Original Assignee: Instrumentverken AB
• Inventors: Malmhall, Roger, Rydergren, Bertil, Silfven, Jan
• Primary Examiner(s): Snow, Walter E.
• Application Number:
  US07/637,352
• Time in Patent Office: 774 Days
• Field of Search: 324/247, 324/253, 324/254, 324/255, 324/260, 324/244
• US Class Current: 324/253
• CPC Class Codes: G01R 33/04 using the flux-gate principle

Abstract

A magnetic field detecting device, particularly for detecting the earth'"'"'s magnetic field, includes one or more amorphous or microcrystalline magnetic fibres having two bistable magnetization states and surrounded by one single measuring coil (103). The measuring coil is supplied with a periodically changing control signal (101a) which is superposed with a detected signal (103a) contingent on the sensed magnetic field. The detected signal is caused to control a flip-flop (122) which influences the working direction of an integrator (101), the output signal of which forms a performance signal in addition to forming said control signal. The performance signal (101c, 106a) is processed in a microprocessor (107), to which a control signal (122b) is also delivered from the flip-flop, and is able to restart the circuit when a control signal fails to appear.

Claims

1. A magnetic field detecting device, particularly for detecting the earth'"'"'s magnetic field, comprising at least one magnetic field detecting means having a sensor intended to produce an electric signal as a value of the sensed magnetic field, said sensor including an elongated member in the form of one or more magnetic, bistable amorphous wires or fibres oriented in the direction of the long axis of said member, and having a single coil surrounding said sensor for contemporary detection of the magnetic field sought for and generation of a reference magnetic field, an integrator driving said single coil by a control signal, and a flip-flop activated by the control signal superposed on a pulse signal generated by means operatively connected to the coil and responsive to the sought magnetic field, the output from the flip-flop operatively connected to said integrator for directional control of said integrator.

2. A device according to claim 1, characterized by two or more magnetic field detecting means (1) oriented at angles to one another, preferably right angles, and in that the magnetic field sensing coil (103) within each detecting means together with corresponding magnetic field sensing coil within the other detecting means is connected to a common measuring circuit which functions to determine the directional sense and magnitude of the sensed magnetic field.

3. A magnetic field detecting device, particularly for detecting the earth'"'"'s magnetic field, comprising at least one magnetic field detecting means (1) which comprises a sensor (2) and is intended to produce an electric signal as a value of the sensed magnetic field, characterized in that the sensor (2) includes an elongated member constructed from one or more magnetic, bistable amorphous metal wires or fibres which are oriented in the direction of the long axis of said member and in that said sensor is at least partially surrounded by one coil (103) operative to sense the sought magnetic field which is intended to alternately change the sensor magnetiztion, the one coil (103) being arranged for contemporary detection of the sought magnetic field and generation of a reference magnetic field, said coil (103) being driven by means of a control signal (101a) produced by an integrator (101), said coil being connected to means causing the sought magnetic field to give rise to a pulse signal (122a) which is superposed on the control signal and which functions to activate a flip-flop (122) operatively connected to the integrator (101) for directional control of the integrator (101), the magnetic field sensing coil (103) being operatively associated with an integrator (101), and further including a measuring circuit (FIG. 4) including a microprocessr (107) to which a performance signal (101c, 106(a)) proportional to the detected magnetic field is delivered from the integrator (101) and also to which a frequency determining control signal (122b) is delivered from the flip-flop (122) in the circuit of the magnetic field sensing coil.

4. A device according to claim 3, characterized in the the microprocessor (107) is intended to deliver a restart signal (107b) to respective flip-flop (122) in the absence of a control signal (122b).

5. A magnetic field detecting device, particularly for detecting the earth'"'"'s magnetic field, comprising at least one magnetic field detecting means (1) which comprises a sensor (2) and is intended to produce an electric signal as a value of the sensed magnetic field, characterized in that the sensor (2) includes an elongated member constructed from one or more magnetic, bistable amorphous metal wires or fibres which are oriented in the direction of the long axis of said member and in that said sensor is at least partially surrounded by one coil (103) operative to sense the sought magnetic field which is intended to alternately change the sensor magnetization, the one coil (103) being arranged for contemporary detection of the sought magnetic field and generation of a reference magnetic field, said coil (103) being driven by means of a control signal (101a) produced by an integrator (101), said coil being connected to means causing the sought magnetic field to give rise to a pulse signal (122a) which is superposed on the control signal and which functions to activate a flip-flop (122) for directional control of the integrator (101), the device characterized by two or more magnetic field detector means (1) oriented at angles to one another, preferably right angles, and in that the magnetic field sensing coil (103) within each detecting means together with corresponding magnetic field sensing coil within the other detecting means is connected to a common measuring circuit (FIG. 4) which functions to determine the directional sense and magnitude of the sensed magnetic field, each magnetic field sensing coil (103) being operatively associated with an integrator (101), said common measuring circuit including a microprocessor (107) to which a performance signal (101c,106a) proportional to the detected magnetic field is delivered from each integrator (101) and also to which a frequency determining control signal (122b) is delivered from respective flip-flop (122) in the circuits of the magnetic field sensing coils.

6. A device according to claim 5, characterized in that the microprocessor (107) is intended to deliver a restart signal (107b) to respective flip-flop (122) in the absence of a control signal (122b).