EP0451839A2
Expired / Lapsed
EP
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Direction finding apparatus
Assignee: Panasonic Holdings Corp
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Filing: 1991-04-11
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Granted: —
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Expires: 2011-04-11
Abstract
Abstract The direction finding apparatus provided in the vehicle (10) computes average data and variance data from output data of the terrestrial magnetism sensor (1) in straight moving, and determines reliability of the detected output data of the terrestrial magnetism sensor (1). The error due to the magnetization of the vehicle (10) is corrected by computing the examined data on each of plural center candidates and selecting a center candidate as a new center coordinate of the present output circle of the terrestrial magnetism. Then, the magnetization of the vehicle (10) is inferred from the new center coordinate, thereby to infer a precise terrestrial magnetism direction.
Inventors
- 👤 Yasuhiro Ihara
- 👤 Mitsuhiro Yamashita
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 19:40
CPC Classifications
G; G01; G01C; G01C17/00; G01C17/38; G01C21/00; G01C21/26; G01C21/28
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
274 words
A direction finding apparatus comprising : terrestrial magnetism sensor means (1) having two sensor elements (1A, 1B) arranged orthogonally to each other for detecting terrestrial magnetism; turn rate sensor means (2) for detecting a turning angle of moving direction of said vehicle (10) at turning; wheel speed sensor means (3) for detecting a mileage in straight moving; straight moving detection means (104) for detecting a straight moving state of said vehicle (10) from output data of said turn rate sensor means (2) and said wheel speed sensor means (3); basic data memory means (105) for storing output data of said terrestrial magnetism sensor means (1) when said straight moving state of said vehicle (10) is detected by said straight moving detection means; data calculation means (106) for calculating average data and variance data computed by the stored data of said basic data memory means (105) and storing said average data and variance data; reliability calculation means (107) which determines a reliability data from said variance data and an order number of said output data of said terrestrial magnetism sensor means (1); magnetization calculation means (108) which infers intensity and direction of the magnetization of said vehicle (10) from said average data, said variance data and said reliability; magnetization memory means (109) for storing said magnetization computed by said magnetization calculation means (108); direction calculation means (110) which infers a course of said vehicle (10) from said output data of said terrestrial magnetism sensor means (1) and said magnetization stored by said magnetization memory means (109); and data output means (7) for outputting a direction of terrestrial magnetism computed by said direction calculation means (110).
Claim 2
Dependent Claim
58 words
A direction finding apparatus in accordance with claim 1, wherein said magnetization calculation means (108) sets plural center candidates (O i ) and selects a center coordinate having smallest sum total which is calculated by multiplying said reliability and difference between intensity of detected average data and a radius (r) of an output circle of said terrestrial magnetism.
Claim 3
Dependent Claim
37 words
A direction finding apparatus in accordance with claim 1, wherein said reliability calculation means (107) obtains a final reliability data on the basis of plural reliability responding to variance data and order number of the detected data;
Claim 4
Dependent Claim
37 words
A direction finding apparatus in accordance with claim 1, wherein said reliability calculation means (107) compute said final reliability data, which is calculated by said variance data, said order number and a distance data in straight moving.
Claim 5
Dependent Claim
53 words
A direction finding apparatus in accordance with claim 1, wherein in said magnetization calculation means (108), all direction of the output circle is divided into plural sectors, thereby to select an average data having high reliability in said divided direction and to compute intensity and direction of the magnetization of said vehicle (10).
References Cited (Backward Citations)
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