Navigation system for vehicles including present position calculating means

• US 5,890,092 A
• Filed: 01/13/1998
• Issued: 03/30/1999
• Est. Priority Date: 09/01/1994
• Status: Expired due to Fees

• Current Assignee: Aisin AW Company Limited (Aisin Corp.)
• Original Assignee: Aisin AW Company Limited (Aisin Corp.)
• Inventors: Hanasaki, Masaharu, Kato, Shinichi, Nimura, Mitsuhiro, Nanba, Akimasa
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US09/006,158
• Time in Patent Office: 441 Days
• Field of Search: 701/224, 701/213, 701/216, 342/357, 342/457
• US Class Current: 701/216
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments

Abstract

In order to calculate the traveling distance and heading of a vehicle in highly accurate fashion, a navigation system is provided with a distance sensor for outputting pulses in proportion to rotation of a wheel, a GPS receiving unit for calculating vehicle speed by GPS reception, acquisition unit for acquiring the number of pulses at the same time as GPS reception, distance correction coefficient calculating unit for calculating GPS traveling distance from the GPS-reception vehicle speed and a time difference between any two points, and calculating a distance correction coefficient from the GPS traveling distance and a pulse difference between two points, and present position calculating unit for calculating present position based upon a corrected distance correction coefficient.

Claims

1. A navigation system for a vehicle, comprising:

receiving means for receiving a signal from a satellite;

heading calculating means for calculating heading of the vehicle based upon a signal from said receiving means;

satellite position sensing means for sensing the position of the satellite based upon the signal from said receiving means;

traveling speed sensing means for sensing traveling speed of the vehicle;

heading error estimating means for estimating error in the heading, obtained by said heading calculating means, based upon the traveling speed obtained by said traveling speed sensing means and the position of the satellite obtained by said satellite position sensing means; and

judging means for judging whether the estimated heading error, which has been estimated by said heading error estimating means, is less than a predetermined value;

wherein the heading calculated by said heading calculating means is employed when the estimated heading error is less than the predetermined value.

2. A navigation system for a vehicle, comprising:

receiving means for receiving a signal from a satellite;

heading calculating means for calculating heading of the vehicle based upon a signal from said receiving means;

satellite position sensing means for sensing the position of the satellite based upon the signal from said receiving means;

traveling speed sensing means for sensing traveling speed of the vehicle;

heading error estimating means for estimating error in the heading, obtained by said heading calculating means, based upon the traveling speed obtained by said traveling speed sensing means and the position of the satellite obtained by said satellite position sensing means;

judging means for judging whether the estimated heading error, which has been estimated by said heading error estimating means, is less than a predetermined value;

heading estimating means for estimating heading of the vehicle;

correction quantity calculating means for calculating a correction quantity that is for correcting the estimated heading, estimated by said heading estimating means, based upon the heading calculated by said heading calculating means and the estimated heading error estimated by said heading error estimating means; and

heading correcting means for correcting the estimating heading, estimated by said heading estimating means, based upon the correction quantity calculated by said correction quantity calculating means.

3. A navigation system for a vehicle, comprising:

receiving means for receiving a signal from a satellite;

heading calculating means for calculating heading of the vehicle based upon a signal from said receiving means;

satellite position sensing means for sensing the position of the satellite based upon the signal from said receiving means;

traveling speed sensing means for sensing traveling speed of the vehicle;

heading error estimating means for estimating error in the heading, obtained by said heading calculating means, based upon the traveling speed obtained by said traveling speed sensing means and the position of the satellite obtained by said satellite position sensing means;

judging means for judging whether the estimated heading error, which has been estimated by said heading error estimating means, is less than a predetermined value;

heading estimating means for estimating heading of the vehicle;

correction quantity calculating means which, when it is judged by said judging means that the estimated heading error is less than the predetermined value, is for calculating a correction quantity that is for correcting the estimated heading, estimated by the heading estimating means, based upon the heading calculated by said heading calculating means and the estimated heading error estimated by said heading error estimating means; and

heading correcting means for correcting the estimated heading, estimated by said heading estimating means, based upon the correction quantity calculated by said correction quantity calculating means.