POSITIONING DEVICE AND POSITIONING METHOD

• US 20120327922A1
• Filed: 04/20/2011
• Published: 12/27/2012
• Est. Priority Date: 05/26/2010
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Takahashi, Makoto, Hashimoto, Jun, Itagaki, Kentaro
• Granted Patent: US 9,008,061 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: G01S 19/48 by combining or switching between position solutions derived from the satellite radio beacon positioning system and position solutions derived from a further system
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence

Abstract

A positioning device for measuring a position includes a WLAN positioning calculation unit that performs first positioning, based on first radio waves from access points; a satellite positioning unit that performs second positioning, based on second radio waves from satellites; a positioning result determination unit that determines whether a positioning result by the WLAN positioning calculation unit exists within a predetermined range from position information or a measured position, based on the position information to be obtained during the second positioning by the satellite positioning unit or the measured position by the satellite positioning unit; and a positioning result adoption determination unit that determines whether the positioning result is adopted, based on a determined result by the positioning result determination unit.

Claims

1. A positioning device for measuring a position comprising:

a WLAN positioning calculation unit that performs first positioning, based on first radio waves from access points;

a satellite positioning unit that performs second positioning, based on second radio waves from satellites;

a positioning result determination unit that determines whether a positioning result by the WLAN positioning calculation unit exists within a predetermined range of position information or a measured position, based on the position information to be obtained during the second positioning by the satellite positioning unit or the measured position by the satellite positioning unit; and

a positioning result adoption determination unit that determines whether the positioning result is adopted, based on a determined result by the positioning result determination unit.

2. The positioning device according to claim 1, further comprising:

a measurement precision determination unit that determines whether measurement precision of the positioning result is acceptable, based on a positioning error of the positioning result by the WLAN positioning calculation unit.

3. The positioning device according to claim 1,

wherein the positioning result determination unit determines reliability of the positioning result by determining whether a first distance between the position information and the positioning result by the WLAN positioning calculation unit is less than or equal to a first threshold value.

4. The positioning device according to claim 3,

wherein the first threshold value is defined based on an error of the position information.

5. The positioning device according to claim 1, further comprising:

a state determination unit that determines a moving state of the positioning device,

wherein the positioning result determination unit determines the reliability of the positioning result by the WLAN positioning calculation unit, based on a history of the measured position and the moving state determined by the state determination unit.

6. The positioning device according to claim 5,

wherein the positioning result determination unit determines the reliability of the positioning result by determining whether a second distance between a newest measured position in the history of the measured position and the positioning result by the WLAN positioning calculation unit is less than or equal to a second threshold value.

7. The positioning device according to claim 6,

wherein the second threshold value is defined based on a time elapsed since the newest measured position is measured and the moving state of the positioning device determined by the state determination unit.

8. The positioning device according to claim 1,

wherein the WLAN positioning calculation unit detects locations of the access points from a database in which identifiers of the access points and the locations of the access points are associated, and the WLAN positioning calculation unit performs the first positioning based on the locations and received signal strengths of the first radio waves.

9. The positioning device according to claim 8, further comprising:

a satellite measurement position acquisition unit that acquires a second measured position to be measured by the satellite positioning unit, when the positioning result determination unit determines that the positioning result is not adopted; and

a positioning result notification unit that reports the second measured position acquired by the satellite measurement position acquisition unit or the positioning result by the WLAN positioning calculation unit to a network.

10. A method of a positioning device that performs positioning, the method comprising:

a WLAN positioning calculation step of performing first positioning, based on first radio waves from access points;

a satellite positioning step of performing second positioning, based on second radio waves from satellites;

a measurement result determination step of determining whether a positioning result by the WLAN positioning calculation step is within a predetermined range of position information or a measured position, based on the position information to be obtained during the second positioning by the satellite positioning step or the measured position by the satellite positioning step; and

a positioning result adoption determination step of determining whether the positioning result is adopted, based on a determined result by the measurement result determination step.