Method and device for eliminating offset of fluxgate magnetometer

Patent metadata

Field	Value
Publication number	US-11519975-B2
Application number	US-202117520745-A
Country	US
Kind code	B2
Filing date	Nov 8, 2021
Priority date	Apr 26, 2021
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

An offset data acquisition method and device of a fluxgate magnetometer are provided by the present disclosure, wherein the offset data acquisition method of the fluxgate magnetometer comprises: controlling the first analog switch, the second analog switch and the third analog switch to change directions within a preset period to obtain eight switch direction combinations between the first analog switch, the second analog switch and the third analog switch; acquiring magnetic field measurement data corresponding to an each of the switch direction combinations; and the magnetic field measurement data comprises x-axis magnetic field measurement data, y-axis magnetic field measurement data and z-axis magnetic field measurement data; and acquiring the offset data based on influence factors of an offset and the magnetic field measurement data within the preset period.

First claim

What is claimed is:

1. An offset data acquisition method of a fluxgate magnetometer, wherein: the offset data acquisition method of the fluxgate magnetometer is applied to the fluxgate magnetometer, the fluxgate magnetometer comprises: a probe, a feedback module, an excitation module, and a sensing module; a first analog switch is provided between the probe and the feedback module, a second analog switch is provided between the probe and the excitation module, and a third analog switch is provided between the probe and the sensing module; the offset data acquisition method of the fluxgate magnetometer comprises:
controlling the first analog switch, the second analog switch and the third analog switch to change directions within a preset period to obtain eight switch direction combinations between the first analog switch, the second analog switch and the third analog switch;
acquiring magnetic field measurement data corresponding to an each of the switch direction combinations; and the magnetic field measurement data comprises x-axis magnetic field measurement data, y-axis magnetic field measurement data and z-axis magnetic field measurement data; and
acquiring the offset data based on influence factors of an offset and the magnetic field measurement data within the preset period, wherein the influence factors include residual magnetism of the probe and environment, coupling leakage of an excitation signal in the probe, a parasitic capacitance effect of the probe, distortion of a probe induced signal, imbalance of an induced signal processing circuit and imbalance of a feedback signal processing circuit.

2. The offset data acquisition method of the fluxgate magnetometer according to claim 1 , wherein acquiring the magnetic field measurement data corresponding to the each of the switch direction combinations, comprising:
acquiring the magnetic field measurement data corresponding to the each of the switch direction combinations, comprising:
acquiring first magnetic field measurement data when the first analog switch, the second analog switch, and the third analog switch are all in a first direction;
acquiring second magnetic field measurement data when the first analog switch is in the first direction and the second analog switch and the third analog switch are in a second direction;
acquiring third magnetic field measurement data when the second analog switch is in the first direction and the first analog switch and the third analog switch are in the second direction;
acquiring fourth magnetic field measurement data when the third analog switch is in the first direction and the first analog switch and the second analog switch are in the second direction;
acquiring fifth magnetic field measurement data when the first analog switch and the second analog switch are in the first direction and the third analog switch is in the second direction;
acquiring sixth magnetic field measurement data when the second analog switch and the third analog switch are in the first direction and the first analog switch is in the second direction;
acquiring seventh magnetic field measurement data when the first analog switch and the third analog switch are in the first direction and the second analog switch is in the second direction; and
acquiring eighth magnetic field measurement data when the first analog switch, the second analog switch, and the third analog switch are all in the second direction.

3. The offset data acquisition method of the fluxgate magnetometer according to claim 1 , wherein acquiring the magnetic field measurement data corresponding to the each of the switch direction combinations, comprising:
acquiring the magnetic field measurement data corresponding to an one of the switch direction combinations in an each subperiod of the preset period to obtain the magnetic field measurement data corresponding to the each of the switch direction combinations, wherein the subperiod is ⅛ of the preset period.

4. The offset data acquisition method of the fluxgate magnetometer according to claim 1 , wherein acquiring the magnetic field measurement data corresponding to the each of the switch direction combinations, comprising:
acquiring original measurement data corresponding to a target switch direction combination, wherein the target switch direction combination is an any one of the eight switch direction combinations;
determining a defective signal in the original measurement data based on a time node of a switch commutation; and
removing the defective signal from the original measurement data to obtain the magnetic field measurement data corresponding to the target switching direction combination.

5. The offset data acquisition method of the fluxgate magnetometer according to claim 4 , wherein determining the defective signal in the original measurement data based on the time node, comprising:
determining the original measurement data within a preset time period after the time node as the defective signal.

6. The offset data acquisition method of the fluxgate magnetometer according to claim 5 , wherein: the preset time period is 0.0052s to 0.0056s.

7. The offset data acquisition method of the fluxgate magnetometer according to claim 1 , wherein the fluxgate magnetometer comprises the probe, the feedback module, the excitation module, the sensing module and a comprehensive controller; the first analog switch is provided between the probe and the feedback module, the second analog switch is provided between the probe and the excitation module, and the second analog switch is provided between the probe and the sensing module; the comprehensive controller is configured to perform a direction control on the first analog switch, the second analog switch and the third analog switch.

8. A non-transitory computer readable storage medium on which a computer program is stored, wherein the computer program is executed by a processor in steps of implementing the offset data acquisition method of the fluxgate magnetometer according to claim 1 .

9. An offset data acquisition device of a fluxgate magnetometer, wherein:
the offset data acquisition device of the fluxgate magnetometer is applied to the fluxgate magnetometer, the fluxgate magnetometer comprises: a probe, a the feedback module, an excitation module, and a sensing module; a first analog switch is provided between the probe and the feedback module, the second analog switch is provided between the probe and the excitation module, and a third analog switch is provided between the probe and the sensing module; the fluxgate magnetometer further comprises a comprehensive controller wherein:
a timer module, configured in the comprehensive controller, controls the first analog switch, the second analog switch and the third analog switch to change the directions within a preset period to obtain the eight switch direction combinations between the first analog switch, the second analog switch and the third analog switch;
a data acquisition module, configured in the comprehensive controller, acquires a magnetic field measurement data corresponding to the each of the switch direction combinations; and the magnetic field measurement data comprises an x-axis magnetic field measurement data, a y-axis magnetic field measurement data and a z-axis magnetic field measurement data; and
an offset calculation module, configured in the comprehensive controller, acquires the offset data based on influence factors of the offset and the magnetic field measurement data within the preset period, wherein the influence factors include a residual magnetism of the probe and the environment, a coupling leakage of the excitation signal in the probe, the parasitic capacitance effect of the probe, a distortion of the probe induc

Assignees

• Inst Geology & Geophysics Cas

Inventors

• Yuan Kaixin
• Du Aiming
• Zhang Ying
• Zhao Lin
• Sun Shuquan
• Feng Xiao
• Li Zhi

Classifications

• G01R33/0041

  using feed-back or modulation techniques · CPC title

• G01R33/02 Primary

  Measuring direction or magnitude of magnetic fields or magnetic flux (G01R33/20 takes precedence) · CPC title

• G01R33/045

  in single-, or multi-aperture elements · CPC title

• G01R33/0206

  Three-component magnetometers · CPC title

• G01C17/38

  Testing, calibrating, or compensating of compasses · CPC title