INDOOR POSITIONING WITH RAKE RECEIVERS

• US 20130039391A1
• Filed: 08/12/2011
• Published: 02/14/2013
• Est. Priority Date: 08/12/2011
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Ericsson Mobile Communications USA Incorporated (Sony Group Corp.)
• Inventors: Skarp, Carl Filip Erik
• Granted Patent: US 8,879,607 B2
• Time in Patent Office: Days
• US Class Current: 375/148
• CPC Class Codes: G01S 11/06 using intensity measurements
• CPC Class Codes: G01S 5/0218 Multipath in signal reception
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 4/023 using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 4/029 Location-based management or tracking services

Abstract

A method and a system for storing a constant path loss exponent corresponding to free space; transmitting a signal; receiving the signal via a rake receiver of a user device; identifying a maximum received signal strength based on a signal strength associated with the signal relative to fingers of the rake receiver; storing a current maximum received signal strength value; determining whether the current maximum received signal strength value is a first maximum received signal strength value; calculating a current indoor position of the user device based on the constant path loss exponent and the current maximum received signal strength value when a determination is that the current maximum received signal strength value is the first maximum received signal strength value; and outputting the current indoor position.

Claims

1. A method comprising:

storing a constant path loss exponent corresponding to free space;

receiving a signal via a rake receiver of a user device;

identifying a maximum received signal strength based on a signal strength associated with the signal relative to fingers of the rake receiver;

storing a current maximum received signal strength value based on the identifying;

determining whether the current maximum received signal strength value is a first maximum received signal strength value;

calculating a current indoor position of the user device based on the constant path loss exponent and the current maximum received signal strength value when a determination is that the current maximum received signal strength value is the first maximum received signal strength value; and

outputting the current indoor position.

2. The method of claim 1, further comprising:

transmitting the signal;

storing previously identified maximum received signal strength values;

comparing a current maximum received signal strength value to one or more previously identified maximum received signal strength values when a determination is that the current maximum received signal strength value is not the first maximum received signal strength value; and

determining whether a difference in maximum received signal strength value indicates receipt by the user device of a direct signal component of the signal or a reflective signal component of the signal.

3. The method of claim 2, further comprising:

calculating a current indoor position of the user device based on the constant path loss exponent and the compared, current maximum received signal strength value when the difference indicates that the compared, current maximum received signal strength value corresponds to the direct signal component of the signal; and

recalculating one or more previous indoor positions of the user device based on the current indoor position of the user device associated with the compared, current maximum received signal strength value.

4. The method of claim 3, further comprising:

recalculating the one or more previous indoor positions of the user device based on at least one of accelerometer data, gyroscope data, or compass data pertaining to the user device.

5. The method of claim 2, further comprising:

storing previous indoor positions of the user device; and

selecting one or more of the previous indoor positions as one or more reference indoor positions when the difference in maximum received signal strength value indicates receipt by the user device of a reflective signal component of the signal.

6. The method of claim 5, further comprising:

calculating a current indoor position of the user device based on the constant path loss exponent, the selected one or more previous indoor positions, and at least one of accelerometer data, gyroscope data, or compass data pertaining to the user device.

7. The method of claim 5, further comprising:

calculating a current indoor position of the user device based on a weighting system associated with the difference in maximum received signal strength value.

8. The method of claim 2, further comprising:

storing at least one of a threshold difference value, a range of difference values, or a maximum received signal strength signature; and

determining whether the difference in maximum received signal strength value indicates receipt by the user device of the direct signal component of the signal or the reflective signal component of the signal based on the at least one of the threshold difference value, the range of difference values, or the maximum received signal strength signature.

9. A user device comprising:

a rake receiver;

one or more memories that store instructions; and

one or more processors that execute the instructions and configures the one or more processors to;

receive a signal via the rake receiver;

identify a maximum received signal strength based on a signal strength associated with the signal relative to fingers of the rake receiver;

store a current maximum received signal strength value based on an identified maximum received signal strength;

determine whether the current maximum received signal strength value is a first maximum received signal strength value; and

calculate a current indoor position of the user device based on a path loss exponent corresponding to free space and the current maximum received signal strength value when a determination is that the current maximum received signal strength value is the first maximum received signal strength value.

10. The user device of claim 9, wherein when calculating the current indoor position, the one or more processors further execute the instructions and configure the one or more processors to:

calculate the current indoor position based on a triangulation algorithm.

11. The user device of claim 9, wherein the one or more processors further execute the instructions and configure the one or more processors to:

store previously identified maximum received signal strength values;

compare a current maximum received signal strength value to one or more previously identified maximum received signal strength values when a determination is that the current maximum received signal strength value is not the first maximum received signal strength value; and

determine whether a difference in maximum received signal strength value indicates receipt by the user device of a direct signal component of the signal or a reflective signal component of the signal.

12. The user device of claim 11, wherein the one or more processors further execute the instructions and configure the one or more processors to:

calculate a current indoor position of the user device based on the path loss exponent and the compared, current maximum received signal strength value when the difference indicates that the compared, current maximum received signal strength value corresponds to the direct signal component of the signal; and

recalculate one or more previous indoor positions of the user device based on the current indoor position of the user device associated with the compared, current maximum received signal strength value.

13. The user device of claim 12, wherein when recalculating, the one or more processors further execute the instructions and configure the one or more processors to:

recalculate the one or more previous indoor positions of the user device based on at least one of accelerometer data, gyroscope data, or compass data pertaining to the user device

14. The user device of claim 11, wherein the one or more processors further execute the instructions and configure the one or more processors to:

store previous indoor positions of the user device; and

select one or more of the previous indoor positions as one or more reference positions when the difference in maximum received signal strength value indicates receipt by the user device of a reflective signal component of the signal.

15. The user device of claim 14, wherein the one or more processors further execute the instructions and configure the one or more processors to:

calculate a current indoor position of the user device based on the path loss exponent, the selected one or more previous indoor positions, and at least one of accelerometer data, gyroscope data, or compass data pertaining to the user device.

16. The user device of claim 9, wherein the path loss exponent is a dynamic value based on at least one of a measurement of temperature, humidity, or pressure of air pertaining to an indoor environment of the user device, or a signal frequency.

17. A non-transitory storage medium storing instructions for:

identifying a maximum received signal strength based on a signal received via a rake receiver;

storing a current maximum received signal strength value based on an identified maximum received signal strength;

determining whether the current maximum received signal strength value is a first maximum received signal strength value; and

calculating one or more distances relative to one or more wireless nodes of an indoor positioning system based on a constant path loss exponent corresponding to free space and the current maximum received signal strength value when a determination is that the current maximum received signal strength value is the first maximum received signal strength value.

18. The non-transitory storage medium of claim 17, further storing instructions for:

storing previously identified maximum received signal strength values;

comparing a current maximum received signal strength value to one or more previously identified maximum received signal strength values when a determination is that the current maximum received signal strength value is not the first maximum received signal strength value; and

determining whether a difference in maximum received signal strength value indicates that the signal includes a direct signal component of the signal or a reflective signal component of the signal.

19. The non-transitory storage medium of claim 18, further storing instructions for:

calculating a current indoor position of the communication device based on the constant path loss exponent and the compared, current maximum received signal strength value when the difference indicates that the compared, current maximum received signal strength value corresponds to the direct signal component of the signal; and

recalculating one or more previous indoor positions of the communication device based on the current indoor position of the communication device associated with the compared, current maximum received signal strength value.

20. The non-transitory storage medium of claim 18, further storing instructions for:

storing previous indoor positions of the communication device;

selecting one or more of the previous indoor positions as one or more reference indoor positions when the difference in maximum received signal strength value indicates receipt by the communication device of a reflective signal component of the signal; and

calculating a current indoor position of the communication device based on the constant path loss exponent, the selected one or more previous indoor positions, and at least one of accelerometer data, gyroscope data, or compass data pertaining to the communication device, wherein the current indoor position is calculated based on triangulation.