Azimuth determination apparatus

• US 4,751,783 A
• Filed: 06/03/1987
• Issued: 06/21/1988
• Est. Priority Date: 06/05/1986
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Kage, Kiyohumi, Akiyama, Susumu, Ina, Katsuhiro, Hirabayashi, Yuji, Akutsu, Kazushi
• Primary Examiner(s): HAROIAN, HARRY
• Application Number:
  US07/057,177
• Time in Patent Office: 384 Days
• Field of Search: 33/356, 33/361, 324/254, 364/571
• US Class Current: 33/361
• CPC Class Codes: G01C 17/38 Testing, calibrating, or compensating of compasses

Abstract

Disclosed is an azimuth determination apparatus attached to a motor vehicle for determinating the forward direction of the vehicle. The azimuth determination apparatus includes an azimuth sensor for generating orthogonal first and second signals indicative of the forward direction of the vehicle. Two azimuth vectors are obtained on the basis of the orthogonal first and second component signals, first components of the two azimuth vectors being maximum and minimum. The determination is made in terms of the fact that the difference between second components of the two azimuth vectors is below a predetermined value. In accordance with the determination, the orthogonal first and second component signals are corrected on the basis of said two azimuth vectors so that the accurate moving direction of the motor vehicle can be obtained irrespective of the remanence of the vehicle.

Claims

1. An azimuth determination apparatus attached to a moving body, comprising:

means for generating orthogonal first and second component signals in response to earth magnetism;

means responsive to said orthogonal first and second component signals for computing the forward direction of said moving body;

means for detecting two of azimuth vectors obtained on the basis of said orthogonal first and second component signals, first components of said two azimuth vectors being maximum and minimum;

means for determining that the difference between second components of said two azimuth vectors is below a predetermined value; and

means for correcting said orthogonal first and second component signals on the basis of said two azimuth vecotrs in accordance with a result of the determination.

2. An azimuth determination apparatus attached to a moving body, comprising:

means for generating orthogonal X and Y component signals in response to earth magnetism;

means responsive to said orthogonal X and Y component signals for computing the forward direction of said moving body;

means for detecting first pair vectors and second pair vectors of azimuth vectors obtained on the basis of said orthogonal X and Y component signals, one of said first pair having a maximum X component and the other of said first pair having a minimum X component, one of said second pair having a maximum Y component and the other of said second pair having a minimum Y component;

means for determining that the difference between the Y components of said first two vectors is below a first predetermined value and the difference between the X components of said second two vectors is below a second predetermined value; and

means for in response to the determination obtaining a X component error on the basis of said first two vectors and obtaining a Y component error on the basis of said second two vectors and for correcting said orthogonal X and Y component signals.