POSITIONING DEVICE, POSITIONING METHOD AND STORAGE MEDIUM STORING PROGRAM

• US 20100318289A1
• Filed: 06/11/2010
• Published: 12/16/2010
• Est. Priority Date: 06/16/2009
• Status: Active Grant

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: SAMBONGI, Masao
• Granted Patent: US 8,473,195 B2
• Time in Patent Office: Days
• US Class Current: 701/201
• CPC Class Codes: G01C 21/1654 with electromagnetic compass
• CPC Class Codes: G01C 21/1656 with passive imaging devices, e.g. cameras
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• 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 positioning device for obtaining position data of a plurality of points on a movement route, including a positioning unit that can measure a present position; a movement measuring unit for measuring a relative positional change; a position calculating unit for calculating position data of the plurality of points on the movement route on the basis of position data of a first reference point and positional change data obtained through measurement of the movement measuring unit; and a correcting unit for correcting the position data of at least one of the plurality of points calculated by the position calculating unit on the basis of difference information representing difference between a position represented by the position data calculated by the position calculating unit and a position represented by a positioning result of the positioning unit with respect to any second reference point on the movement route.

Claims

1. A positioning device for obtaining position data of a plurality of points on a movement route, comprising:

a positioning unit that can measure a present position without requiring any past position data serving as a reference;

a movement measuring unit for measuring a relative positional change;

a position calculating unit for calculating position data of the plurality of points on the movement route on the basis of position data of a first reference point and positional change data obtained through measurement of the movement measuring unit; and

a correcting unit for correcting the position data of at least one of the plurality of points calculated by the position calculating unit on the basis of difference information representing difference between a position represented by the position data calculated by the position calculating unit and a position represented by a positioning result of the positioning unit with respect to any second reference point on the movement route.

2. The positioning device according to claim 1, wherein the correcting unit adds a displacement amount represented by the difference information to a series of the position data calculated by the position calculating unit at a rate which is larger according as a point represented by each of the series of the position data is farther away from the first reference point with respect to a movement distance along the movement route, thereby correcting the position data calculated by the position calculating unit.

3. The positioning device according to claim 1, wherein the correcting unit executes correcting calculation containing a correcting term in which on the basis of a total route length measured by the movement measuring unit from the first reference point to the second reference point, a first route length measured by the movement measuring unit from the first reference point till a point at which position data of a correction target is obtained, and the difference information at the second reference point, a rate of the first route length to the total route length is set as a coefficient, a displacement amount represented by the difference information is multiplied by the coefficient, and the displacement amount obtained by the multiplication is added to the position data of the correction target.

4. The positioning device according to claim 3, wherein the correcting unit subjects the displacement amount obtained by the multiplication to predetermined weighting, and adds the weighted displacement amount to the position data of the correction target.

5. The positioning device according to claim 1, wherein the correcting unit executes correcting calculation containing a correcting term in which on the basis of a total time length taken to move from the first reference point to the second reference point, a first time length taken to move from the first reference point till a point at which position data of a correction target is obtained, and the difference information at the second reference point, a rate of the first time length to the total time length is set as a coefficient, a displacement amount represented by the difference information is multiplied by the coefficient, and the displacement amount obtained by the multiplication is added to the position data of the correction target.

6. The positioning device according to claim 5, wherein the correcting unit subjects the displacement amount obtained by the multiplication to predetermined weighting, and adds the weighted displacement amount to the position data of the correction target.

7. The positioning device according to claim 1, wherein the difference information contains information of a distance and a direction between two points represented by two position data.

8. The positioning device according to claim 1, wherein the correcting unit calculates a multiplying power between a distance from the first reference point to the second reference point which is determined on the basis of the position data of the position calculating unit and a distance from the first reference point to the second reference point which is determined on the basis of a positioning result of the positioning unit, and deleting an error from the position data of the plurality of points on the movement route calculated by the position calculating unit on the assumption that a distance between adjacent two points along the movement route which is determined on the basis of the position data calculated by the position calculating unit contains the error corresponding to a length obtained by multiplication of the multiplying power and the distance between the adjacent two points, thereby correcting the position data calculated by the position calculating unit.

9. The positioning device according to claim 8, wherein the correcting unit calculates difference in a direction from the first reference point to the second reference point which is determined on the basis of the position data of the position calculating unit and a direction from the first reference point to the second reference point which is determined on the basis of a positioning result of the positioning unit, and deleting a uniform direction error from the position data of the plurality of points on the movement route calculated by the position calculating unit on the assumption that the uniform direction error is added accumulatively to the position data of the plurality of points on the movement route in proportion to a movement amount.

10. The positioning device according to claim 1, wherein the difference information contains direction information and distance information, and the correcting unit calculates a ratio between a distance from the first reference point to the second reference point determined on the basis of the position data of the position calculating unit and a distance from the first reference point to a correction target point determined on the basis of the position data of the position calculating unit, calculates a rotational angle from the second reference point till the correction target point around the first reference point which is determined on the basis of the position data of the position calculating unit, increases or reduces the distance information of the difference information in accordance with the ratio, varies the direction information of the difference information in accordance with the rotational angle, and adds difference information containing the increased or reduced distance information and the varied direction information to the position data of the correction target point calculated by the position calculating unit.

11. The positioning device according to claim 1, further comprising a storage unit for storing movement record data containing the position data of the plurality of points calculated by the position calculating unit, wherein the correcting unit corrects the position data of the plurality of points contained in the movement record data.

12. The positioning device according to claim 1, wherein measurement of the movement measuring unit and calculation of the position data by the position calculating unit are continuously performed while measurement of the present position by the positioning unit is intermittently performed, and the correcting unit sets two points at which position data is intermittently measured by the positioning unit as the first and the second reference points, and corrects the position data calculated by the position calculating unit.

13. A positioning method for obtaining position data of a plurality of points on a movement route by using a positioning unit which can measure a present position and a movement measuring unit for measuring a relative positional change, comprising:

a position calculating step of calculating position data of the plurality of points on the movement route on the basis of position data of a first reference point and positional change data obtained through measurement of the movement measuring unit;

a difference information obtaining step of obtaining difference information representing difference between a position represented by the position data calculated in the position calculating step and a position represented by a positioning result of the positioning unit with respect to any second reference point on the movement route; and

a correcting step of correcting the position data of at least one of the plurality of points calculated in the position calculating step on the basis of the difference information.

14. A storage medium storing a program readable by a computer that receives measurement results from a positioning unit for measuring a present position and a movement measuring unit for measuring a relative positional change and obtains position data of a plurality of points on a movement route, the storage medium storing a program making the computer execute:

a position calculating function of calculating position data of the plurality of points on the movement route on the basis of position data of a first reference point and positional change data obtained through measurement of the movement measuring unit;

a difference information obtaining function of obtaining difference information representing difference between a position represented by the position data calculated by the position calculating function and a position represented by a positioning result of the positioning unit with respect to any second reference point on the movement route; and

a correcting function of correcting the position data of at least one of the plurality of points calculated by the position calculating function on the basis of the difference information.