Location detecting apparatus

• US 5,307,277 A
• Filed: 06/03/1992
• Issued: 04/26/1994
• Est. Priority Date: 06/18/1991
• Status: Expired due to Fees

• Current Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Inventors: Hirano, Kazuo
• Primary Examiner(s): Chin, Gary
• Application Number:
  US07/893,063
• Time in Patent Office: 692 Days
• Field of Search: 364/443, 364/444, 364/449, 364/454, 364/457, 342/357, 342/451, 342/457, 340/988, 340/990, 340/995, 73/178 R, 33/356, 33/357
• US Class Current: 701/207
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments
• CPC Class Codes: G01S 19/40 Correcting position, velocity or attitude

Abstract

A location detecting apparatus comprising an autonomous location detecting unit mounted in a moving body to calculate a distance traveled by the moving body and an estimated heading of the moving body and to detect an estimated location of the moving body on the basis of the distance traveled and the estimated heading, a receiving unit for detecting a location of the moving body by receiving waves from satellites circling around the Earth in predetermined orbits and for providing location information corresponding to the detected location, a unit to detect a difference of location between the location detected by the receiving unit and the estimated location, a location correcting unit which corrects the estimated location to the location detected by the receiving unit when the difference of location is more than a first predetermined value, a magnetic sensor for detecting an heading of the moving body by sensing a geomagnetic field, and a heading correcting unit which corrects the estimated heading to the heading detected by the magnetic sensor, when the difference of location is more than the first predetermined value after the estimated location was corrected and before the moving body travels a predetermined distance.

Claims

1. A location detecting apparatus comprising:

autonomous location detecting means mounted in a moving body to calculate a distance traveled by said moving body and an estimated heading of said moving body and to detect an estimated location of said moving body on the basis of said distance traveled and said estimated heading;

receiving means for detecting a location of said moving body by receiving waves from satellites circling around the Earth in predetermined orbits and for providing location information corresponding to the detected location;

means to detect a difference of location between said location detected by said receiving means and said estimated location detected by said autonomous location detecting means;

location correcting means which corrects said estimated location to said location detected by said receiving means when said difference of location is more than a first predetermined value;

a magnetic sensor for detecting an heading of said moving body by sensing a geomagnetic field; and

heading correcting means which corrects said estimated heading calculated by said autonomous location detecting means to said heading detected by said magnetic sensor, when said difference of location is more than said first predetermined value after said estimated location was corrected by said location correcting means and before said moving body travels a predetermined distance.

2. A location detecting apparatus as set forth in claim 1, which further comprises means that, when said difference of location is more than a second predetermined value greater than said first predetermined value, corrects said estimated heading in said autonomous location detecting means to said heading detected by said magnetic sensor independently of whether or not said estimated location was corrected before an occurrence of the greater difference of location.