Apparatus for displaying travel path

• US 4,887,081 A
• Filed: 12/09/1987
• Issued: 12/12/1989
• Est. Priority Date: 12/15/1986
• Status: Expired due to Fees

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Iihoshi, Akira, Nakamura, Yukinobu, Yasui, Shinichiro
• Primary Examiner(s): Orsino, Joseph A.
• Assistant Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US07/130,415
• Time in Patent Office: 734 Days
• Field of Search: 340/988, 340/990, 340/995, 73/178 R, 73/505, 364/449, 364/424, 364/460, 364/521, 33/356
• US Class Current: 340/995.28
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments
• CPC Class Codes: G01D 7/00 Indicating measured values
• CPC Class Codes: G05D 1/0259 using magnetic or electromagnetic means
• CPC Class Codes: G05D 1/027 comprising intertial navigation means, e.g. azimuth detector inertial navigation G01C21/16; inertial navigation combined with non-inertial navigation instruments G01C21/165
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30

Abstract

An apparatus for displaying a travel path of a running body in which a direction detector includes a geomagnetism sensor as well as a rate-type sensor, such as a gyroscope or gas rate sensor (which includes a flow sensor for detecting a degree of displacement of a gas flow produced by an angular velocity applied thereto) for detecting an angular volocity of change of yawing direction of the moving body, in which a difference in angle between directions detected by the rate-type sensor and the geomagnetism sensor is found and temporarily stored when a power source is temporarily turned OFF during operation of the running path displaying apparatus, and then a declination of the direction detected by the geomagnetism sensor is corrected, depending upon the stored difference in angle, when the power source is turned ON again.

Claims

1. An apparatus for displaying a travel path, direction, and current location of a running body on a X-Y coordinate map with a north direction corresponding to the Y-direction of the X-Y coordinates in which the current location is successively computed from the respective outputs of a distance detector and of a direction detector comprising:

the direction detector including a geomagnetism sensor and a rate-type sensor;

the rate-type sensor detecting angular velocity;

means for finding and storing a difference in angle between a direction detected by the rate-type sensor and a direction detected by the geomagnetism sensor at the time when a power source is turned off during travel path displaying operation; and

means for correcting declination of the direction detected by the geomagnetism sensor by adding the stored difference in angle to the direction detected by the geomagnetism sensor at the time when the power source is turned on again, wherein when the power source is turned on said geomagnetism sensor corrected for declination of the detected direction is used exclusively to detect vehicle direction for a predetermined time sufficient for said rate-type sensor to achieve stability in performance, wherein once said stability in performance is achieved, signal processing means causes change over from the geomagnetism sensor to said rate-type sensor for exclusively detecting vehicle direction.