Method and apparatus for map matching

• US 9,746,331 B1
• Filed: 12/08/2015
• Issued: 08/29/2017
• Est. Priority Date: 12/15/2014
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Yu, Jing, Chen, Jian, Liu, BoChih, Jia, Zhike
• Primary Examiner(s): Sample, Jonathan L
• Application Number:
  US14/962,803
• Time in Patent Office: 630 Days
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01C 21/30 Map- or contour-matching
• CPC Class Codes: G01S 19/42 Determining position
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled
• CPC Class Codes: G01S 5/0063 of measured values, i.e. measurement on base station and position calculation on mobile
• CPC Class Codes: G01S 5/0252 Radio frequency fingerprinting

Abstract

Aspects of the disclosure provide an apparatus for determining a matched position of a mobile device in a map. The apparatus can have a map matching system that can include a link selector that is configured to select candidate links in the map based on a previous matched position and a path length threshold, and a matching processor that is configured to determine a matched link in the candidate links based on an equivalent distance from an estimated position to a link in the candidate links and determine a current matched position on the matched link. In an embodiment, the map matching system can further include an initializer that is configured to determine a matched position based on an equivalent distance from a first estimated position to an initial candidate link in the map.

Claims

1. An apparatus for determining a matched position of a mobile device in a map, the apparatus having a map matching system, the map matching system comprising:

a link selector that is configured to select candidate links from links in the map, wherein a link in the map having a path length between a previous matched position and the link in the map shorter than a path length threshold is selected to be a candidate link; and

a matching processor that is configured to,

determine a matched link in the candidate links based on an equivalent distance from an estimated position of the mobile device to a link in the candidate links, wherein the estimated position of the mobile device is indicated by position data generated from a positioning circuit in the mobile device,

determine a current matched position on the matched link, and

provide the current matched position to a circuit providing a location-based service.

2. The apparatus of claim 1, wherein the map matching system further comprising:

an initializer that is configured to determine a matched position based on an equivalent distance from a first estimated position to an initial candidate link in the map.

3. The apparatus of claim 2, wherein the equivalent distance from the estimated position to the link in the candidate links represents a combination of contributions of the minimum distance between the estimated position and the link in the candidate links and a heading difference between the mobile device and the link in the candidate links, and

the equivalent distance from the first estimated position to the initial candidate link in the map represents a combination of contributions of the minimum distance between the first estimated position and the initial candidate link in the map and a heading difference between the mobile device and the initial candidate link in the map.

4. The apparatus of claim 2, wherein the initializer determines the matched position based on the equivalent distance from the first estimated position to the initial candidate link in the map comprises:

select initial candidate links based on a minimum distance threshold and a heading difference threshold;

determine an initial matched link based on an equivalent distance from the first estimated position to the initial candidate link in the map; and

determine the matched position on the initial matched link.

5. The apparatus of claim 1, wherein the matching processor determines the matched link in the candidate links based on the equivalent distance from the estimated position to the link in the candidate links comprises:

select a link in the candidate links to which the equivalent distance from the estimated position is the shortest to be the matched link.

6. The apparatus of claim 1, wherein the matching processor determines the current matched position on the matched link comprises:

project the estimated position onto the matched link to determine the current matched position on the matched link.

7. The apparatus of claim 1, further comprising:

the positioning circuitry that is configured to generate position data indicative of the first estimated position and the estimated position, and heading information indicative of a heading of the mobile device;

motion sensors that are configured to detect a moving state of the mobile device and provide measurements of the moving state to the positioning circuitry; and

a map database that is configured to provide map data to the map matching system,

wherein the map matching system is configured to receive the position data and the heading information from the positioning circuitry and receive map data from the map database.

8. The apparatus of claim 7, wherein the positioning circuitry comprises one of the following positioning systems:

a satellite-based positioning system;

a radio-based positioning system; and

a dead-reckoning system.

9. The apparatus of claim 1, wherein the map is an indoor floor map.

10. A method for determining a matched position of a mobile device in a map, comprising:

selecting candidate links from links in the map, wherein a link in the map having a path length between a previous matched position and the link in the map shorter than a path length threshold is selected to be a candidate link;

determining a matched link in the candidate links based on an equivalent distance from an estimated position of the mobile device to a link in the candidate links, wherein the estimated position of the mobile device is indicated by position data generated from a positioning circuit in the mobile device;

determining a current matched position on the matched link; and

providing the current matched position to a circuit providing a location-based service.

11. The method of claim 10, further comprising:

determining a matched position based on an equivalent distance from a first estimated position to an initial candidate link in the map.

12. The method of claim 11, wherein the equivalent distance from the estimated position to the link in the candidate links represents a combination of contributions of the minimum distance between the estimated position and the link in the candidate links and a heading difference between the mobile device and the link in the candidate links, and

the equivalent distance from the first estimated position to the initial candidate link in the map represents a combination of contributions of the minimum distance between the first estimated position and the initial candidate link in the map and a heading difference between the mobile device and the initial candidate link in the map.

13. The method of claim 11, wherein determining the matched position based on the equivalent distance from the first estimated position to the initial candidate link in the map comprises:

selecting initial candidate links based on a minimum distance threshold and a heading difference threshold;

determining an initial matched link based on an equivalent distance from the first estimated position to the initial candidate link in the map; and

determining the matched position on the initial matched link.

14. The method of claim 10, wherein determining the matched link in the candidate links based on the equivalent distance from the estimated position to the link in the candidate links comprises:

selecting a link in the candidate links to which the equivalent distance from the estimated position is the shortest to be the matched link.

15. The method of claim 10, wherein determining the current matched position on the matched link comprises:

projecting the estimated position onto the matched link to determine the current matched position on the matched link.

16. The method of claim 10, further comprising:

receiving position data indicative of the first estimated position and the estimated position and heading information indicative of a heading of the mobile device from positioning circuitry; and

receiving map data from a map database.

17. The method of claim 16, wherein the positioning circuitry comprises one of the following positioning systems:

a satellite-based positioning system;

a radio-based positioning system; and

a dead-reckoning system.

18. The method of claim 10, wherein the map is an indoor floor map.