Apparatus and Method for Determining a Current Position of a Mobile Device

• US 20070184850A1
• Filed: 01/22/2007
• Published: 08/09/2007
• Est. Priority Date: 07/22/2004
• Status: Active Grant

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Meyer, Steffen, Bliesze, Marcus, Hupp, Jurgen, Sippl, Melanie
• Granted Patent: US 7,783,302 B2
• Time in Patent Office: Days
• US Class Current: 455/456.100
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01S 5/02521 using a radio-map

Abstract

An apparatus for determining a current position of a mobile device in an environment in which at least one transmitter is disposed includes a means for providing a cartographic map of the environment, the cartographic map including field strength reference values at reference points, a means for determining a field strength value, a means for deriving a reference point within reach that can be reached starting from a previous position of the mobile device by movement of the mobile device in the environment within a predetermined time interval, from the cartographic map of the environment, and a comparator for comparing the field strength value with a field strength reference value at the reference point within reach in order to determine the current position. By including the cartographic map of the environment, the position determination is simplified.

Claims

1. An apparatus for determining the current position of a mobile device in an environment in which at least one transmitter is disposed, comprising:

a provider for providing a cartographic map of the environment, the cartographic map including field strength reference values at reference points;

a determinator for determining a field strength value;

an identifier for deriving reference points within reach that can be reached starting from a previous position of the mobile device by movement of the mobile device in the environment within a predetermined time interval, from the cartographic map of the environment; and

a comparator for comparing the field strength value with the field strength reference values at the reference points within reach,

wherein the reference point the field strength reference value of which most likely corresponds to the field strength value is established as current position.

2. The apparatus of claim 1, wherein the means for determining the field strength value is formed to measure the field strength value at the current position.

3. The apparatus of claim 1, wherein the determinator for determining a field strength value is formed to measure field strength values at regular measurement intervals.

4. The apparatus of claim 1, wherein the determinator for determining a field strength value is formed to determine the field strength reference values.

5. The apparatus of claim 4, wherein the determinator for determining a field strength value is formed to determine a field strength reference value by averaging among the currently measured field strength value and a mean value of measured field strength values determined at an earlier point in time.

6. The apparatus of claim 1, wherein the provider for providing the cartographic map is formed to enter a field strength value into the cartographic map of the environment at an accompanying reference point in order to update the cartographic map.

7. The apparatus of claim 1, wherein the identifier for deriving a reference point within reach is formed to establish a routing map, the routing map including possible connections between reference points that can be reached by movement of the mobile device.

8. The apparatus of claim 7, wherein the identifier for deriving the reference point within reach is formed to determine a shortest connection between a first reference point and a second reference point.

9. The apparatus of claim 7, wherein the identifier for deriving the reference point within reach is formed to determine the routing map using a routing algorithm.

10. The apparatus of claim 1, wherein the identifier for deriving the reference point within reach is formed to determine the reference point within reach using a routing algorithm.

11. The apparatus of claim 1, wherein the comparator is formed to determine the reference point within reach as the current position if the field strength reference value matches the field strength value at the current position within a predetermined value interval.

12. A method for determining a current position of a mobile device within an environment in which at least one transmitter is disposed, comprising:

providing a cartographic map of the environment, the cartographic map of the environment including field strength reference values at reference points;

determining a field strength value at the current position;

deriving reference points within reach that can be reached starting from a previous position of the mobile terminal by movement of the mobile terminal in the environment within a predetermined time interval, from the cartographic map of the environment; and

comparing the field strength value to the field strength reference values at the reference points within reach,

characterized by the step of establishing the reference point the field strength reference value of which most likely corresponds to the field strength value as current position.

13. A computer program with a program code for performing, when the program is executed on a computer, a method for determining a current position of a mobile device within an environment in which at least one transmitter is disposed, comprising:

providing a cartographic map of the environment, the cartographic map of the environment including field strength reference values at reference points;

determining a field strength value at the current position;

deriving reference points within reach that can be reached starting from a previous position of the mobile terminal by movement of the mobile terminal in the environment within a predetermined time interval, from the cartographic map of the environment; and

comparing the field strength value to the field strength reference values at the reference points within reach,

characterized by the step of establishing the reference point the field strength reference value of which most likely corresponds to the field strength value as current position.