Apparatus for detecting the position of a vehicle

• US 5,493,294 A
• Filed: 01/04/1995
• Issued: 02/20/1996
• Est. Priority Date: 04/15/1992
• Status: Expired due to Fees

• Current Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Inventors: Morita, Kazuya
• Primary Examiner(s): SWARTHOUT, BRENT
• Application Number:
  US08/368,759
• Time in Patent Office: 412 Days
• Field of Search: 340/988, 340/993, 340/990, 340/995, 364/449, 342/457, 342/357
• US Class Current: 340/988
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments
• CPC Class Codes: G01S 19/13 Receivers
• CPC Class Codes: G01S 19/50 whereby the position solution is constrained to lie upon a particular curve or surface, e.g. for locomotives on railway tracks

Abstract

A vehicle position detecting apparatus comprises satellite designating means for designating at least three satellites from a plurality of satellites revolving around the earth to form a designated satellite combination, vehicle position estimating means for estimating a vehicle position on the basis of the vehicle position data supplied from the designated satellite combination and received by electric wave receiving means mounted on the vehicle, satellite combination fixing means for fixing the designated satellite combination to make constant an offset representing a deviation between the estimated vehicle position and a true vehicle position, and true vehicle position calculating means for calculating the true vehicle position on the basis of the offset and the estimated vehicle position. Various errors detected by sensors or means forming part of the vehicle position detecting apparatus can be minimized so as to enhance the accuracy of the vehicle position at a higher level.

Claims

1. An apparatus for detecting the position of a vehicle, comprising:

electric wave receiving means for receiving electric waves from a plurality of satellites revolving around the earth to supply vehicle position data;

satellite designating means for designating at least three satellites from said plurality of satellites to form a designated satellite combination;

vehicle position estimating means for estimating an estimated vehicle position on the basis of said vehicle position data supplied from said designated satellite combination and received by said electric wave receiving means, said estimated vehicle position including a position error area symmetrically surrounding the estimated vehicle position;

satellite combination fixing means for fixing said designated satellite combination to make constant an offset representing a deviation between said estimated vehicle position and a true vehicle position;

road network data storing means for storing road network data having a plurality of road network patterns, said estimated vehicle position and said position error area being indicated on said road network patterns;

estimated table making means for dividing said position error area into a plurality of mesh sections, for determining a value of the probability of the vehicle existence in each mesh section of said position error area and making an estimated table containing estimated values each corresponding to each of the determined values of the probability in all mesh sections of said position error area;

repeating means for repeating, as the vehicle travels, the operation of said estimated table making means at intervals under the condition that said designated satellite combination is fixed by said satellite combination fixing means;

table updating means for updating a previously updated estimated table having previously updated estimated values each time said estimated table is made by said estimated table making means, by adding the estimated values of the estimated table to the previously updated estimated values, respectively, of the previously updated estimated table;

deviation calculating means for calculating a deviation between said estimated vehicle position and the position of a mesh section of said position error area specified by a largest value within the updated estimated values of said updated estimated table, said deviation being indicative of said offset; and

true vehicle position calculating means for calculating the true vehicle position on the basis of said offset and said estimated vehicle position.

2. An apparatus as set forth in claim 1, in which the calculating said deviation by said deviation calculating means is performed when the largest updated estimated value of said updated table exceeds a predetermined value.

3. An apparatus as set forth in claim 1, which further comprises:

direction detecting means for detecting the travel direction of said vehicle;

distance detecting means for detecting the travel distance of said vehicle; and

vehicle position determining means for determining the real present vehicle position on travel roads on the basis of said travel direction detected by said direction detecting means, said travel distance detected by said distance detecting means, said true vehicle positions calculated by said true vehicle position calculating means, and said road network data stored by said road network data storing means.