Portable position detector and position management system

• US 6,546,336 B1
• Filed: 09/23/1999
• Issued: 04/08/2003
• Est. Priority Date: 09/26/1998
• Status: Expired due to Fees

• Current Assignee: Transtechnology Ltd.
• Original Assignee: Jatco Limited (Nissan Motor Co., Ltd.)
• Inventors: Matsuoka, Yoshio, Yamamoto, Akito
• Primary Examiner(s): Louis-Jacques, Jacques H.
• Assistant Examiner(s): Broadhead, Brian J.
• Application Number:
  US09/401,199
• Time in Patent Office: 1,293 Days
• Field of Search: 701/207, 701/216, 701/217, 701/213, 701/117
• US Class Current: 701/213
• CPC Class Codes: G01C 22/006 Pedometers

Abstract

A portable position detector is equipped with a pedometer, a geomagnetic sensor, and an acceleration sensor. With the pedometer, the moved distance of a walker is detected by a calculation of “the number of steps×the length of a step”. With the walking time per step detected with the acceleration sensor, the length of a step is corrected so that it corresponds to the walking state. The moved direction of the walker is detected with the geomagnetic sensor. With this, the moved position of the walker is accurately detected by self-contained navigation. Particularly, even in the case where the position detector is located in a forest or between buildings where a signal cannot be received from a global positioning system (GPS) due to high buildings, banks, and forests, the position detector with a portable size and weight applicable to a walker can know with a practically sufficient degree of accuracy the position of a person carrying this portable detector by self-contained navigation.

Claims

1. A portable position detector for detecting a moved position of a walking body, comprising:

walking-motion detection means for measuring a value related to a walking motion caused by movement of said walking body;

acceleration detection means for detecting acceleration of the value related to the walking motion caused by movement of said walking body;

moved-distance estimation means for estimating the moved distance of said walking body, based on both a number of steps detected from an output of said walking-motion detection means and a step length changed according to horizontal acceleration of said walking body or the magnitude of a change in the horizontal acceleration detected by acceleration detection means;

moved-direction detection means for detecting a direction or direction of movement of said walking body caused by movement of said walking body;

moved-direction determination means further comprising

means for detecting two points further comprising a first point at which said walking body arrives substantially at a highest position and a second point at which said walking body lands, based on an output of said walking-motion detection means, and

means for determining a moved direction at a specific location related to at least one of the first point and the second point and specified in a range between said first position and a succeeding position being a subsequent highest position at which said walking body arrives; and

moved-position estimation means for estimating a position of said walking body after movement, based on said moved distance of said walking body estimated by said moved-distance estimation means and said specific moved direction determined by said moved-direction determination means.

2. The portable position detector as set forth in claim 1, wherein said moved-distance estimation means counts the number of steps on the basis of a vertical geomagnetic change caused by walking of said walking body, detected by said walking-motion detection means, and also estimates the moved distance from a relation of the counted number of steps and the length of a step and wherein the step length is corrected based on the output of said acceleration detection means when the estimation is performed.

3. The portable position detector as set forth in claim 1, wherein said moved-direction determination means judges and detects at least one of the first point and the second point from a vertical acceleration change caused by walking of said walking body, and also determines a moved direction of said walking body at a specific point as a specific moved direction, the specific point being at least one of said first point and second point, or being a point delayed therefrom by a predetermined time.

4. The portable position detector as set forth in claim 3, wherein said predetermined time that is delayed by said moved-direction determination means is determined as a proportional portion of a walking step period from a walking cycle.

5. The portable position detector as set forth in claim 3, wherein said predetermined time that is delayed by said moved-direction determination means is set to a time at which said specific point goes to a state in which a landed foot and a next foot are positioned side by side.

6. The portable position detector as set forth in claim 1, wherein said moved-direction determination means judges and detects at least one of the first point and the second point from a vertical geomagnetic change caused by walking of said walking body, and also determines a moved direction of said walking body at a specific point as a specific moved direction, the specific point being at least one of said first point and second point, or being a point delayed therefrom by a predetermined time.

7. The portable position detector as set forth in claim 6, wherein said predetermined time that is delayed by said moved-direction determination means is determined as a proportional portion of a walking step period from a walking cycle.

8. The portable position detector as set forth in claim 1, wherein said moved-distance estimation means detects changing environment from acceleration change or geomagnetic change caused by movement of said walking body, also changes said length of a step, based on the detected changing environment, and calculates said moved-distance estimation and wherein the step length is corrected based on the output of said acceleration detection means when the calculation is made.

9. The portable position detector as set forth in claim 8, wherein the correction of said step length is performed by making said step length shorter than a step length during a walk on a level path, when it is judged by the detection of said changing environment that a walking path has a slope greater than a predetermined value.

10. The portable position detector as set forth in claim 1, further comprising:

a unit for receiving radio waves from global positioning system (GPS) satellites and measuring the current position of said walking body; and

position correction means for correcting the current position estimated by said position estimation means, when the current position is measured with said unit.

11. The portable position detector as set forth in claim 10, wherein

when the moved direction detected by said moved-direction detection means or said specific moved direction determined by said moved-direction determination means is within a predetermined direction width and also when it is judged by the detection of a changing environment that a cumulated of steps or a cumulated moved-distance, in which a vertical amount of movement is within a predetermined width, is a straight-advanced walk on a level path which continues for a predetermined time or more, a correction of the step length in said moved-distance estimation means is performed by a value obtained by dividing a calculated distance by said cumulated number of steps, the calculated distance being calculated from positions measured at a starting point and an ending point of said straight-advanced walk on a level path by said unit.

13. The portable position detector as set forth in claim 2, wherein

even when said time required for one step of a walk is shorter than normal time required for one step of a walk, said step length is corrected so that said time required for one step of a walk becomes shorter, if the horizontal acceleration of said walking body or a change in said acceleration detected by said acceleration detection means during this walking is less than a first predetermined value;

and

even when said time required for one step of a walk is longer than normal time required for one step of a walk, said step length is corrected so that said time required for one step of a walk becomes longer, if the horizontal acceleration of said walking body or a change in said acceleration detected by said acceleration detection means during this walking is greater than a second predetermined value.

15. The portable position detector as set forth in claim 2, wherein said moved-direction determination means judges and detects at least one of the first point and the second point from a vertical geomagnetic change caused by walking of said walking body, and also determines a moved direction of said walking body at a specific point as a specific moved direction, the specific point being at least one of said first point and second point, or being a point delayed therefrom by a predetermined time.

12. A portable position detector for detecting a moved position of a walking body, comprising:

walking-motion detection means for measuring a value related to a walking motion caused by movement of said walking body;

acceleration detection means for detecting acceleration of the value related to the walking motion caused by movement of said walking body;

moved-distance estimation means for estimating the moved distance of said walking body, based on both a number of steps detected from an output of said walking-motion detection means and a step length changed in a direction where the step length becomes a wider step length as a time required for one step of a walk detected from an output of said walking-motion detection means becomes shorter;

moved-direction detection means for detecting a direction or direction of movement of said walking body caused by movement of said walking body;

moved-direction determination means further comprising

means for detecting two points further comprising a first point at which said walking body arrives substantially at a highest position and a second point at which said walking body lands, based on an output of said walking-motion detection means, and

means for determining a moved direction at a specific location related to at least one of the first point and the second point and specified in a range between said first position and a succeeding position being a subsequent highest position at which said walking body arrives; and

moved-position estimation means for estimating a position of said walking body after movement, based on said moved distance of said walking body estimated by said moved-distance estimation means and said specific moved direction determined by said moved-direction determination means.

14. The portable position detector as set forth in claim 12, wherein said moved-direction determination means judges and detects at least one of the first point and the second point from a vertical acceleration change caused by walking of said walking body, and also determines a moved direction of said walking body at a specific point as a specific moved direction, the specific point being at least one of said first point and second point, or being a point delayed therefrom by a predetermined time.

16. The portable position detector as set forth in claim 12, wherein said moved-distance estimation means detects changing environment from acceleration change or geomagnetic change caused by movement of said walking body, also changes said length of a step, based on the detected changing environment, and calculates said moved-distance estimation and wherein the step length is corrected based on the output of said acceleration detection means when the calculation is made.

17. The portable position detector as set forth in claim 12, further comprising:

a unit for receiving radio waves from global positioning system (GPS) satellites and measuring a current position of said walking body; and

position correction means for correcting the current position estimated by said position estimation means, when the current position is measured with said unit.

18. A position management system comprising:

a portable position detector for detecting a moved position of a walking body, the portable position detector including

(1) walking-motion detection means for measuring a value related to a walking motion caused by movement of said walking body,

(2) acceleration detection means for detecting acceleration of a value related to the walking motion caused by movement of said walking body,

(3) moved-distance estimation means for estimating the moved distance of said walking body, based on both a number of steps detected from an output of said walking-motion detection means and a step length changed according to either the time required for one step of a walk detected during said walking motion, or-horizontal acceleration of said walking body detected by acceleration detection means, or a magnitude of a change in the horizontal acceleration,

(4) moved-direction detection means for detecting a direction or direction of movement of said walking body caused by movement of said walking body,

(5) moved-direction determination means further comprising

means for detecting two points further comprising a first point at which said walking body arrives substantially at a highest position and a second point at which said walking body lands, based on an output of said walking-motion detection means, and

means for determining a moved direction at a specific location related to at least one of the first point and the second point and specified in a range between said first position and a succeeding position being a subsequent highest position at which said walking body arrives; and

(6) moved-position estimation means for estimating a position of said walking body after movement, based on said moved distance of said walking body estimated by said moved-distance estimation means and said specific moved direction determined by said moved-direction determination means, and

(7) transmission means for transmitting at least one piece of information of output information from said walking-motion detection means, from said moved-distance estimation means, from said moved-direction determination means, and from said moved-position estimation means; and

a base station including (1) reception means for receiving the output information transmitted by said transmission means of said portable position detector and (2) display means for displaying a moved position of said portable position detector, based on the information from said reception means.

19. The position management system as set forth in claim 18, wherein

at least a portion of information necessary for a process of calculating a position of said portable position detector on the basis of a GPS signal received by said portable position detector is transmitted from said portable position detector to said base station;

said base station receives said portion of information and performs said position calculating process; and

in said portable position detector, a calculating process is shared with said portable position detector and said base station so that said base station executes processes other than said position calculating process.