Electronic azimuth meter and timepiece

• US 6,662,459 B2
• Filed: 07/27/2001
• Issued: 12/16/2003
• Est. Priority Date: 08/01/2000
• Status: Active Grant

• Current Assignee: Seiko Instruments Incorporated (Seiko Group)
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Kato, Kazuo
• Primary Examiner(s): Fulton, Christopher W.
• Assistant Examiner(s): JOHNSON, AMY COHEN
• Application Number:
  US09/916,525
• Publication Number:
  US 20020023362A1
• Time in Patent Office: 872 Days
• Field of Search: 333/56, 333/55.R, 333/57, 333/61, 333/58, 333/59
• US Class Current: 33/356
• CPC Class Codes: G01C 17/38 Testing, calibrating, or compensating of compasses

Abstract

A method for adjusting an electronic azimuth meter comprising the steps of performing a magnetic field generating sequence by generating a sequence of magnetic fields used for adjusting the electronic azimuth meter, the sequence of magnetic fields commencing with generation of a strong magnetic field having a magnitude larger than that of the Earth'"'"'s geomagnetism, and providing, within the strong magnetic field, an electronic azimuth meter having a magnetic detector and a control unit for performing a data acquisition and adjustment process in response to detection of the strong magnetic field, so that the control unit commences the data acquisition and adjustment process when the strong magnetic field is detected and the electronic azimuth meter is not electrically connected to a magnetic field generating apparatus which generates the sequence of magnetic fields.

Claims

1. A method of adjusting an electronic azimuth meter comprising the steps of:

providing an electronic azimuth meter having a magnetic detector and a control circuit for performing an adjustment process in response to detection of a strong magnetic field having a magnitude larger than that of the Earth'"'"'s geomagnetism;

generating a sequence of magnetic fields including the strong magnetic field in accordance with an adjusting magnetic field generating sequence to adjust the electronic azimuth meter;

performing an adjusting data acquisition sequence using the control unit of the electronic azimuth meter for acquiring output data of magnetic sensors of the magnetic detector for adjusting the electronic azimuth meter in synchronization with the magnetic field generating sequence while the electronic azimuth meter is disposed in a magnetic field region produced by the magnetic field generating apparatus; and

starting the adjusting data acquisition sequence of the electronic azimuth meter by generating the strong magnetic field.

2. A method of adjusting an electronic azimuth meter according to claim 1;

wherein the step of generating the sequence of magnetic fields includes the steps of generating magnetic fields in four azimuths.

3. A method of adjusting an electronic azimuth meter according to claim 1;

wherein the step of generating the sequence of magnetic fields includes the step of generating magnetic fields used for adjusting a span and offset of an output of the magnetic detector of the electronic azimuth meter.

4. A method of adjusting an electronic azimuth meter according to claim 1;

wherein the step of generating the sequence of magnetic fields includes the step of generating magnetic fields used for adjusting a span and offset of an output of an A/D converter connected to an output of magnetic sensors of the magnetic detector.

5. A system for adjusting an electronic azimuth meter, the system comprising:

a magnetic field generating apparatus for performing an adjusting magnetic field generating sequence by generating magnetic fields in a given sequence starting with a strong magnetic field having a magnitude larger than that of the Earth'"'"'s geomagnetism, the strong magnetic field being used for starting a process of adjusting the electronic azimuth meter; and

an electronic azimuth meter having a magnetic detector and a control unit for acquiring output data of the magnetic detector by performing a data acquisition sequence for adjusting the electronic azimuth meter in synchronization with the magnetic field generating sequence and starting the data acquisition sequence when the magnetic detector is arranged below a magnetic field produced by the magnetic field generating apparatus in the magnetic field generating sequence and senses the strong magnetic field.

6. In a system for adjusting an electronic azimuth meter:

a magnetic field generating apparatus for generating a strong magnetic field having a magnitude larger than that of the Earth'"'"'s geomagnetism; and

a control unit for controlling the magnetic field generating apparatus to generate a sequence of magnetic fields starting with the strong magnetic field, the strong magnetic field being used to control the electronic azimuth meter to commence an adjusting data acquisition sequence in synchronization with the sequence of magnetic fields by acquiring output data of a magnetic detector.

7. In an electronic azimuth meter having a magnetic detector and a control unit for acquiring output data of the magnetic detector in accordance with a process of acquiring data for adjusting the electronic azimuth meter in synchronization with a sequence of generated magnetic fields:

a control unit for starting the process of acquiring data for adjusting the electronic azimuth meter when a strong magnetic field having a magnitude larger than that of the Earth'"'"'s geomagnetism representing a start of the sequence of magnetic fields is detected by the magnetic detector.

8. An electronic timepiece having a main body;

a display;

a timepiece movement; and

an electronic azimuth meter;

wherein the azimuth meter comprises the electronic azimuth meter according to claim 7.

9. An electronic azimuth meter according to claim 7;

wherein the magnetic detector comprises X-direction and Y-direction magnetic sensors disposed in a main body for detecting magnetic field components in an X-Y plane; and

further comprising a main body;

a magnetic part forming at locations in the X-direction and the Y-direction magnetic sensors magnetic fields by being magnetized by the Earth'"'"'s geomagnetism; and

an azimuth calculating circuit for calculating the azimuth of the main body.

10. An electronic azimuth meter according to claim 9;

wherein the magnetic part includes a battery arranged at a center of the main body.

11. An electronic azimuth meter according to claim 9;

wherein the azimuth calculating circuit calculates the magnetic field components of the Earth'"'"'s geomagnetism in the X and the Y directions and calculates the azimuth of the azimuth meter based on the magnetic field components of the Earth'"'"'s geomagnetism.

12. An electronic azimuth meter according to claim 11;

wherein the azimuth calculating circuit includes an azimuth data storing portion for storing the output values of the X-direction and the Y-direction magnetic sensors obtained at four azimuths comprised of north, south, east and west of the Earth'"'"'s geomagnetism.

13. An electronic azimuth meter according to claim 12;

further comprising a phase difference data storing portion for storing phase difference data in the X-direction and the Y-direction calculated from the detected magnetic field values of the X-direction and the Y-direction magnetic sensors with regard to four azimuths of east, west, south and north of the Earth'"'"'s geomagnetism.

14. A method for adjusting an electronic azimuth meter comprising the steps of:

performing a magnetic field generating sequence by generating a sequence of magnetic fields used for adjusting the electronic azimuth meter, the sequence of magnetic fields commencing with generation of a strong magnetic field having a magnitude larger than that of the Earth'"'"'s geomagnetism;

providing, within the strong magnetic field, an electronic azimuth meter having a magnetic detector and a control unit for performing a data acquisition and adjustment process in response to detection of the strong magnetic field, so that the control unit commences the data acquisition and adjustment process when the strong magnetic field is detected and the electronic azimuth meter is not electrically connected to a magnetic field generating apparatus which generates the sequence of magnetic fields.

15. A method for adjusting an electronic azimuth meter according to claim 14;

wherein the data acquisition and adjustment process is performed in synchronization with the magnetic field generating sequence.

16. A method for adjusting an electronic azimuth meter according to claim 14;

wherein the step of performing a magnetic field generating sequence includes the steps of generating magnetic fields in four azimuths.

17. A method for adjusting an electronic azimuth meter according to claim 14;

wherein the step of performing a magnetic field generating sequence includes the step of generating magnetic fields used for adjusting a span and offset of an output of the magnetic detector of the electronic azimuth meter.

18. A method for adjusting an electronic azimuth meter according to claim 14;

wherein the step of performing a magnetic field generating sequence includes the step of generating magnetic fields used for adjusting a span and offset of an output of an A/D converter connected to an output of magnetic sensors of the magnetic detector.