POSITIONING APPARATUS, POSITIONING METHOD, AND STORAGE MEDIUM FOR MEASURING POSITION USING BOTH AUTONOMOUS NAVIGATION AND GPS

• US 20120062414A1
• Filed: 09/14/2011
• Published: 03/15/2012
• Est. Priority Date: 09/15/2010
• Status: Active Grant

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Sambongi, Masao
• Granted Patent: US 8,692,709 B2
• Time in Patent Office: Days
• US Class Current: 342/357.25
• 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: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled

Abstract

A positioning apparatus including: a first positioning unit which intermittently receives signals from satellites and carries out a first position measurement; a second positioning unit which carries out a second position measurement by adding information of a moving direction and a moving amount to positional information of a reference position; a positioning control unit which obtains positional information corresponding to positions along a movement path by the first position measurement and the second position measurement; a reference position updating unit which updates the positional information of the reference position based on a result of the first position measurement; a distance calculating unit which calculates a distance between two positions, i.e., between the reference position and a position obtained by the second position measurement; and a positioning timing control unit which controls timing to carry out the first position measurement based on the distance.

Claims

1. A positioning apparatus comprising:

a first positioning unit which intermittently receives signals from a plurality of positioning satellites and carries out a first position measurement;

a second positioning unit which carries out a second position measurement by continuously measuring a moving direction and a moving amount of a user and by adding information of the moving direction and the moving amount to positional information of a reference position;

a positioning control unit which obtains positional information corresponding to positions along a movement path by the first position measurement and the second position measurement;

a reference position updating unit which updates the positional information of the reference position based on a result of the first position measurement when the first position measurement is carried out;

a distance calculating unit which calculates a distance between two positions, i.e., between the reference position and a position obtained by the second position measurement; and

a positioning timing control unit which controls timing to carry out the first position measurement based on the distance between the two positions.

2. The positioning apparatus according to claim 1, wherein the positioning timing control unit makes the first positioning unit carry out the first position measurement when it is determined that the position obtained by the second position measurement is moving toward the reference position, based on a series of distances between two positions calculated by the distance calculating unit when a series of second position measurements are carried out.

3. The positioning apparatus according to claim 2, further comprising a prohibiting unit which prohibits the first position measurement based on the distance between the two positions when the distance between the two positions is shorter than a predetermined distance.

4. The positioning apparatus according to claim 2, further comprising a correcting unit which corrects a series of positional information sets obtained by the second position measurement based on the result of the first position measurement when the first position measurement is carried out.

5. The positioning apparatus according to claim 2, further comprising a precision level obtaining unit which obtains precision level representing position measurement precision at a time of the first position measurement,

wherein the result of the first position measurement is not used when the position measurement precision is lower than a predetermined precision threshold value.

6. The positioning apparatus according to claim 1, wherein the positioning timing control unit makes the first positioning unit carry out the first position measurement when the distance between the two positions exceeds a predetermined distance threshold value.

7. The positioning apparatus according to claim 6, further comprising a precision level obtaining unit which obtains precision level representing position measurement precision at a time of the first position measurement,

wherein the result of the first position measurement is not used when the position measurement precision is lower than a predetermined precision threshold value.

8. The positioning apparatus according to claim 7, further comprising a threshold value updating unit which makes the predetermined precision threshold value lower and makes the distance threshold value higher when the position measurement precision is lower than the precision threshold value.

9. A positioning method for obtaining positional information corresponding to positions along a movement path by using a first positioning unit and a second positioning unit, the first positioning unit intermittently receiving signals from a plurality of positioning satellites and carrying out a first position measurement;

and the second positioning unit carrying out a second position measurement by continuously measuring a moving direction and a moving amount of a user and by adding information of the moving direction and the moving amount to positional information of a reference position;

the method comprising;

(a) obtaining the positional information corresponding to the positions along the movement path by the first position measurement and the second position measurement;

(b) updating the positional information of the reference position based on a result of the first position measurement when the first position measurement is carried out;

(c) calculating a distance between two positions, i.e., between the reference position and a position obtained by the second position measurement; and

(d) controlling timing to carry out the first position measurement based on the distance between the two positions.

10. The positioning method according to claim 9, wherein step (d) makes the first positioning unit carry out the first position measurement when it is determined that the position obtained by the second position measurement is moving toward the reference position, based on a series of distances between two positions calculated by step (c) when a series of second position measurements are carried out.

11. A computer readable storage medium having recorded thereon a computer program for controlling a computer which communicates with a first positioning unit and a second positioning unit, the first positioning unit intermittently receiving signals from a plurality of positioning satellites and carrying out a first position measurement;

and the second positioning unit carrying out a second position measurement by continuously measuring a moving direction and a moving amount of a user and by adding information of the moving direction and the moving amount to positional information of a reference position;

wherein the program controls the computer to function as;

a positioning control unit which obtains positional information corresponding to positions along a movement path by the first position measurement and the second position measurement;

a reference position updating unit which updates the positional information of the reference position based on a result of the first position measurement when the first position measurement is carried out;

a distance calculating unit which calculates a distance between two positions, i.e., between the reference position and a position obtained by the second position measurement; and

a positioning timing control unit which controls timing to carry out the first position measurement based on the distance between the two positions.

12. The storage medium storing the program according to claim 11, wherein the program further controls the computer so that the positioning timing control unit makes the first positioning unit carry out the first position measurement when it is determined that the position obtained by the second position measurement is moving toward the reference position, based on a series of distances between two positions calculated by the distance calculating unit when a series of second position measurements are carried out.