Direction indicating device

• US 20040111907A1
• Filed: 11/25/2003
• Published: 06/17/2004
• Est. Priority Date: 12/11/2002
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Sato, Fumitaka, Takeuchi, Kunihito
• Granted Patent: US 7,093,371 B2
• Time in Patent Office: Days
• US Class Current: 33/355R
• CPC Class Codes: G01C 17/38 Testing, calibrating, or compensating of compasses

Abstract

A direction indicating device in which a current display direction is determined in consideration of the historical information of a direction of vehicle specified by a direction specifying unit 1 and a previous display direction, to be specific, in a case where the current direction of vehicle specified by the direction specifying unit 1 agrees with a previous direction of vehicle, the current display direction is changed to agree with the current direction of vehicle, and in a case where the current direction of vehicle specified by the direction specifying unit 1 is different from the previous direction of vehicle, the current display direction is made to agree with the previous display direction.

Claims

1. A direction indicating device comprising:

a direction specifying unit that detects geomagnetism to specify a direction of vehicle;

a display direction determining unit that determines a current display direction in consideration of historical information of the direction of vehicle specified by the direction specifying unit and a previous display direction; and

a direction providing unit that provides the current display direction determined by the display direction determining unit.

2. The direction indicating device as claimed in claim 1, wherein the direction specifying unit repeatedly detects geomagnetism and finds a mean value of the geomagnetism during a sampling period and specifies a directional section to which the mean value of the geomagnetism belongs as a direction of vehicle.

3. The direction indicating device as claimed in claim 1, wherein in a case where the current direction of vehicle specified by the direction specifying unit agrees with a previous direction of the vehicle, the display direction determining unit makes the current display direction agree with the current direction of vehicle.

4. The direction indicating device as claimed in claim 2, wherein in a case where the current direction of vehicle specified by the direction specifying unit agrees with the previous direction of vehicle, if the latest mean value of geomagnetism is within a margin region to prevent chattering at a boundary of the directional sections, the display direction determining unit makes the current display direction agree with the previous display direction, and if the latest mean value of geomagnetism is without the margin region, the display direction determining unit makes the current display direction agree with the current direction of vehicle.

5. The direction indicating device as claimed in claim 4, wherein in a case where the current direction of vehicle specified by the direction specifying unit, the previous direction of vehicle and the second previous direction of vehicle agree with each other, the display direction determining unit makes the margin region to prevent chattering at the boundary of the respective directional sections narrower.

6. The direction indicating device as claimed in claim 5, wherein in a case where the current direction of vehicle specified by the direction specifying unit is different from the previous direction of vehicle, the display direction determining unit returns the margin region to prevent chattering to an original size.

7. The direction indicating device as claimed in claim 1, wherein in a case where the current direction of vehicle specified by the direction specifying unit is different from the previous direction of vehicle, the display direction determining unit makes the current display direction agree with the previous display direction.

8. The direction indicating device as claimed in claim 7, wherein even in a case where the current direction of vehicle is different from the previous direction of vehicle, the display direction determining unit determines a traveling direction of the vehicle from the current direction of vehicle, the previous direction of vehicle, and previous display direction and if the traveling direction is constant, the display direction determining unit updates the current display direction to the traveling direction side of the vehicle by one directional section from the previous display direction.