Method of and apparatus for calculating position of movable body in navigation system, method of and apparatus for correcting the position, and program storage device readable by the apparatus

• US 5,949,375 A
• Filed: 04/30/1997
• Issued: 09/07/1999
• Est. Priority Date: 05/02/1996
• Status: Expired due to Fees

• Current Assignee: Pioneer Electronics (USA) Incorporated (Pioneer Corporation)
• Original Assignee: Pioneer Electronics (USA) Incorporated (Pioneer Corporation)
• Inventors: Kuwahara, Shingo, Ishiguro, Motoki
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US08/841,102
• Time in Patent Office: 860 Days
• Field of Search: 342/457, 701/207, 701/216
• US Class Current: 342/457
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G01S 19/13 Receivers
• CPC Class Codes: G01S 19/40 Correcting position, velocity or attitude
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled

Abstract

A method of calculating a present position of a movable body for use in a navigation system, is provided with the processes of: measuring an electric-wave-based measurement position which is a position of the movable body measured on the basis of electric waves for positional measurement, which are transmitted from satellites accompanied by time data indicating an electric-wave-based measurement time which is a time when measuring the electric-wave-based measurement position, at the electric-wave-based measurement time; measuring a self-sustained measurement position which is a position of the movable body measured on the basis of data from self-sustained type sensors built in the movable body; calculating a time difference between the electric-wave-based measurement time and a time when measuring the self-sustained measurement position; correcting the electric-wave-based measurement position on the basis of the calculated time difference; and calculating the present position of the movable body on the basis of the corrected electric-wave-based measurement position and the self-sustained measurement position.

Claims

1. A method of calculating a present position of a movable body for use in a navigation system for navigating said movable body, said method comprising:

an electric-wave-based measurement process of measuring an electric-wave-based measurement position which is a position of said movable body measured on the basis of electric waves for positional measurement, which are transmitted from satellites, and which include time data indicating an electric-wave-based measurement time which is a time when measuring the electric-wave-based measurement position, at the electric-wave-based measurement time;

a self-sustained measurement process of measuring a self-sustained measurement position which is a position of said movable body measured on the basis of data from self-sustained type sensors built in said movable body;

a time difference calculation process of calculating a time difference between a time when measuring the electric-wave-based measurement position by said electric-wave-based measurement process and a time when measuring the self-sustained measurement position by said self-sustained measurement process;

a correction process of correcting the electric-wave-based measurement position on the basis of the calculated time difference; and

a present position calculation process of calculating the present position of said movable body on the basis of the corrected electric-wave-based measurement position and the self-sustained measurement position.

2. A method according to claim 1, wherein said correction process corrects the electric-wave-based measurement position by superimposing a moving distance of said movable body, which corresponds to the calculated time difference and is calculated on the basis of the data from said self-sustained type sensors, onto the electric-wave-based measurement position, so as to calculate the corrected electric-wave-based measurement position.

3. A method of calculating a present position of a movable body for use in a navigation system having a distance sensor for navigating said movable body, said distance sensor cyclically outputting distance data, which indicates a moving distance of said movable body measured in a self-sustained way once every predetermined cycle and includes an identifier for identifying the distance data at each cycle, said method comprising:

a distance measurement process of outputting the distance data one after another in connection with a movement of said movable body;

a drop out detection process of detecting a drop out of the distance data on the basis of said identifier included in the outputted distance data;

a pseudo distance data generation process of generating pseudo distance data corresponding to the dropped out distance data on the basis of the distance data outputted before the dropped out distance data and the distance data outputted after the dropped out distance data, when the drop out is detected by said drop out detection process;

a moving distance calculation process of calculating the moving distance by adding the generated pseudo distance data onto the distance data outputted after the dropped out distance data, when the drop out is detected by said drop out detection process; and

a present position calculation process of calculating the present position of said movable body on the basis of the calculated moving distance.

4. A method of correcting a present position of a movable body onto a position on a route, where said movable body is supposed to exist, corresponding to the present position for use in a navigation system for navigating said movable body, said method comprising:

a vector generation process of generating a moving vector corresponding to a movement of said movable body with respect to a previously corrected position of said movable body as a start point of said moving vector;

a display process of displaying a position of an end point of the generated moving vector as the present position of said movable body; and

a correct process of correcting the position of the end point to a position on the route corresponding to the position of the end point after displaying the position of the end point by said display process.

5. A method according to claim 4, further comprising a redisplay process of displaying the corrected position on the route as the present position of said movable body.

6. An apparatus for calculating a present position of a movable body for use in a navigation system for navigating said movable body, said apparatus comprising:

an electric-wave-based measurement means for measuring an electric-wave-based measurement position which is a position of said movable body measured on the basis of electric waves for positional measurement, which are transmitted from satellites, and which include time data indicating an electric-wave-based measurement time which is a time when measuring the electric-wave-based measurement position, at the electric-wave-based measurement time;

a self-sustained measurement means for measuring a self-sustained measurement position which is a position of said movable body measured on the basis of data from self-sustained type sensors built in said movable body;

a time difference calculation means for calculating a time difference between a time when measuring the electric-wave-based measurement position by said electric-wave-based measurement means and a time when measuring the self-sustained measurement position by said self-sustained measurement means;

a correction means for correcting the electric-wave-based measurement position on the basis of the calculated time difference; and

a present position calculation means for calculating the present position of said movable body on the basis of the corrected electric-wave-based measurement position and the self-sustained measurement position.

7. An apparatus according to claim 6, wherein said correction means corrects the electric-wave-based measurement position by superimposing a moving distance of said movable body, which corresponds to the calculated time difference and is calculated on the basis of the data from said self-sustained type sensors, onto the electric-wave-based measurement position, so as to calculate the corrected electric-wave-based measurement position.

8. An apparatus for calculating a present position of a movable body for use in a navigation system having a distance sensor for with navigating said movable body, said distance sensor cyclically outputting distance data, which indicates a moving distance of said movable body measured in a self-sustained way once every predetermined cycle and includes an identifier for identifying the distance data at each cycle, said apparatus comprising:

a distance measurement means for outputting the distance data one after another in connection with a movement of said movable body;

a drop out detection means for detecting a drop out of the distance data on the basis of said identifier included in the outputted distance data;

a pseudo distance data generation means for generating pseudo distance data corresponding to the dropped out distance data on the basis of the distance data outputted before the dropped out distance data and the distance data outputted after the dropped out distance data, when the drop out is detected by said drop out detection means;

a moving distance calculation means for calculating the moving distance by adding the generated pseudo distance data onto the distance data outputted after the dropped out distance data, when the drop out is detected by said drop out detection means; and

a present position calculation means for calculating the present position of said movable body on the basis of the calculated moving distance.

9. An apparatus for correcting a present position of a movable body onto a position on a route, where said movable body is supposed to exist, corresponding to the present position for use in a navigation system for navigating said movable body, said apparatus comprising:

a vector generation means for generating a moving vector corresponding to a movement of said movable body with respect to a previously corrected position of said movable body as a start point of said moving vector;

a display means for displaying a position of an end point of the generated moving vector as the present position of said movable body; and

a correct means for correcting the position of the end point to a position on the route corresponding to the position of the end point after displaying the position of the end point by said display means.

10. An apparatus according to claim 9, wherein said display means displays the corrected position on the route as the present position of said movable body.

11. A program storage device readable by an apparatus for calculating a present position of a movable body for use in a navigation system for navigating said movable body, tangibly embodying a program of instructions executable by said apparatus to perform method processes for calculating the present position of said movable body, said method processes comprising:

an electric-wave-based measurement process of measuring an electric-wave-based measurement position which is a position of said movable body measured on the basis of electric waves for positional measurement, which are transmitted from satellites, and which include time data indicating an electric-wave-based measurement time which is a time when measuring the electric-wave-based measurement position, at the electric-wave-based measurement time;

a self-sustained measurement process of measuring a self-sustained measurement position which is a position of said movable body measured on the basis of data from self-sustained type sensors built in said movable body;

a time difference calculation process of calculating a time difference between a time when measuring the electric-wave-based measurement position by said electric-wave-based measurement process and a time when measuring the self-sustained measurement position by said self-sustained measurement process;

a correction process of correcting the electric-wave-based measurement position on the basis of the calculated time difference; and

a present position calculation process of calculating the present position of said movable body on the basis of the corrected electric-wave-based measurement position and the self-sustained measurement position.

12. A program storage device according to claim 11, wherein said correction process corrects the electric-wave-based measurement position by superimposing a moving distance of said movable body, which corresponds to the calculated time difference and is calculated on the basis of the data from said self-sustained type sensors, onto the electric-wave-based measurement position, so as to calculate the corrected electric-wave-based measurement position.

13. A program storage device readable by an apparatus for calculating a present position of a movable body for use in a navigation system having a distance sensor for navigating said movable body, said distance sensor cyclically outputting distance data, which indicates a moving distance of said movable body measured in a self-sustained way once every predetermined cycle and includes an identifier for identifying the distance data at each cycle, tangibly embodying a program of instructions executable by said apparatus to perform method processes for calculating the present position of said movable body, said method processes comprising:

a distance measurement process of outputting the distance data one after another in connection with a movement of said movable body;

a drop out detection process of detecting a drop out of the distance data on the basis of said identifier included in the outputted distance data;

a pseudo distance data generation process of generating pseudo distance data corresponding to the dropped out distance data on the basis of the distance data outputted before the dropped out distance data and the distance data outputted after the dropped out distance data, when the drop out is detected by said drop out detection process;

a moving distance calculation process of calculating the moving distance by adding the generated pseudo distance data onto the distance data outputted after the dropped out distance data, when the drop out is detected by said drop out detection process; and

a present position calculation process of calculating the present position of said movable body on the basis of the calculated moving distance.

14. A program storage device readable by an apparatus for correcting a present position of a movable body onto a position on a route, where said movable body is supposed to exist, corresponding to the present position for use in a navigation system for navigating said movable body, tangibly embodying a program of instructions executable by said apparatus to perform method processes for correcting the present position of said movable body, said method processes comprising:

a vector generation process of generating a moving vector corresponding to a movement of said movable body with respect to a previously corrected position of said movable body as a start point of said moving vector;

a display process of displaying a position of an end point of the generated moving vector as the present position of said movable body; and

a correct process of correcting the position of the end point to a position on the route corresponding to the position of the end point after displaying the position of the end point by said display process.

15. A program storage device according to claim 14, wherein said method processes further comprise a re-display process of displaying the corrected position on the route as the present position of said movable body.