Indoor positioning using joint likelihoods

• US 8,412,239 B1
• Filed: 06/07/2012
• Issued: 04/02/2013
• Est. Priority Date: 04/10/2012
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Palanki, Ravi, Naguib, Ayman Fawzy
• Primary Examiner(s): PATEL, MAHENDRA R
• Application Number:
  US13/491,393
• Time in Patent Office: 299 Days
• Field of Search: 455/456.6, 455/522, 455/11.1, 455/456.3, 455/458, 455/12.1, 455/436, 342/450, 340/7.52, 370/331
• US Class Current: 455/456.6
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: G01S 5/0278 involving statistical or probabilistic considerations G01S5/0252, G01S5/0294 take precedence
• CPC Class Codes: H04W 4/025 using location based information parameters
• CPC Class Codes: H04W 4/33 for indoor environments, e.g. buildings

Abstract

Apparatus, systems and methods for estimating a position of a mobile terminal (MT) using joint probability distribution values are disclosed. In an example, the MT is capable of receiving signals from a plurality of access points. The MT receives a map of expected measurements for a parameter observable by the MT, from any of a plurality of hypothesis locations. The expected measurements are predictive of a value of the parameter observed by the MT, when the MT is proximal that hypothesis location. The MT captures measurements of the parameter for the plurality of access points, computes interim vectors for the hypothesis locations using the captured and expected measurements, computes joint probability distributions for the interim vectors using a covariance matrix, and filters the joint probability distributions to produce an estimated position of the MT.

Claims

1. A method in a mobile terminal for estimating a position of the mobile terminal, the method comprising:

receiving an expected measurement map indicative of an expected measurement of one or more parameters by the mobile terminal, the expected measurement map being associated with a plurality of communication devices and a plurality of hypothesis locations, wherein receiving the expected measurement map comprises receiving a set of expected measurement values associated with the plurality of communication devices and the plurality of hypothesis locations;

receiving parameters of a matrix corresponding to the expected measurement map;

capturing, by the mobile terminal, actual measurements of the one or more parameters for the plurality of communication devices, wherein each of the actual measurements and the expected measurement map comprise values indicative of a delay in a communication path between the mobile terminal and one or more of the plurality of communication devices; and

utilizing the received one or more parameters and actual measurements to estimate the position of the mobile terminal, wherein estimating the position of the mobile terminal includes

computing a respective interim vector from the actual measurements and the expected measurement map for each hypothesis location;

computing joint probability distribution values as an exponential of a matrix product using the interim vector and the matrix to produce a joint probability distribution value; and

filtering the joint probability distribution value to estimate the position of the mobile terminal.

2. The method of claim 1, wherein the parameters of the matrix comprise a covariance matrix.

3. The method of claim 1, wherein the parameters of the matrix comprise an inverse of a covariance matrix.

4. The method of claim 1, wherein the expected measurement map comprise values indicative of expected received signal strength by the mobile terminal.

5. The method of claim 1, wherein the interim vector comprises a difference between the actual measurements and corresponding expected measurements.

6. The method in of claim 1, wherein computing the interim vector comprises removing an unknown variable.

7. The method of claim 6, wherein the removing of the unknown variable comprises removing an antenna gain of the mobile terminal.

8. The method of claim 6, wherein the removing of the unknown variable comprises removing a fixed processing delay of one or more of the plurality of communication devices.

9. The method of claim 1, wherein the method is implemented in a server in communication with the mobile terminal, and further comprising receiving, from the mobile terminal, captured measurements, from the position of the mobile terminal, for the plurality of communication devices.

10. A mobile terminal for estimating a position of the mobile terminal, comprising:

a matrix reception unit to receive parameters of a matrix;

an expected measurement map reception unit to receive an expected measurement map indicative of an expected measurement of one or more parameters by the mobile terminal, the expected measurement map being associated with a plurality of communication devices and a plurality of hypothesis locations, wherein the expected measurement map reception unit is further configured to receive a set of expected measurement values associated with the plurality of communication devices and the plurality of hypothesis locations;

a measurement capture unit to capture actual measurements of one or more parameters from the position of the mobile terminal for the plurality of communication devices, wherein each of the actual measurements and the expected measurement map comprise values indicative of a delay in a communication path between the mobile terminal and one or more of the plurality of communication devices;

a joint probability distribution computation unit to use compute an interim vector to compute joint probability distribution values as an exponential of a matrix product using the interim vector and the matrix;

a computation unit coupled to the matrix reception unit and the measurement capture unit, and to use the received one or more parameters and actual measurements and the joint probability distribution values to estimate the position of the mobile terminal, wherein the computation unit is coupled to a filter for filtering the joint probability distribution values to estimate the position of the mobile terminal.

11. The mobile terminal of claim 10, wherein the parameters of the matrix comprise a covariance matrix.

12. The mobile terminal of claim 10, wherein the parameters of the matrix comprise an inverse of a covariance matrix.

13. The mobile terminal of claim 10, wherein computing the interim vector comprises removing an unknown variable.

14. The mobile terminal of claim 13, wherein the removing of the unknown variable comprises removing an antenna gain of the mobile terminal.

15. The mobile terminal of claim 13, wherein the removing of the unknown variable comprises removing a fixed processing delay of one or more of the plurality of communication devices.

16. A mobile terminal for estimating a position of the mobile terminal, the mobile terminal comprising:

means for receiving an expected measurement map indicative of an expected measurement of one or more parameters by the mobile terminal, the expected measurement map being associated with a plurality of communication devices and a plurality of hypothesis locations, wherein the means for receiving the expected measurement map comprises means for receiving a set of expected measurement values associated with the plurality of communication devices and the plurality of hypothesis locations;

means for receiving parameters of a matrix corresponding to the expected measurement map;

means for capturing, by the mobile terminal, actual measurements of the one or more parameters for a plurality of communication devices, wherein each of the actual measurements and the expected measurement map comprise values indicative of a delay in a communication path between the mobile terminal and one or more of the plurality of communication devices;

means for estimating the position of the mobile terminal using the received one or more parameters and actual measurements, wherein means for estimating the position of the mobile terminal include instructions for

computing a respective interim vector from the actual measurements and the expected measurement map for each hypothesis location,

computing joint probability distribution values as an exponential of a matrix product using the interim vector and the matrix to produce a joint probability distribution value, and

filtering the joint probability distribution value to estimate the position of the mobile terminal.

17. The mobile terminal of claim 16, wherein the means for estimating comprises means for removing an unknown variable.

18. The mobile terminal of claim 17, wherein the means for estimating comprises means for removing an antenna gain of the mobile terminal.

19. A device comprising:

a processor;

a transceiver operable to send and receive wireless signals, wherein the processor is coupled to receive data from the transceiver; and

a non-transitory memory having stored thereon instructions for configuring the processor for;

receiving an expected measurement map indicative of an expected measurement of one or more parameters by a mobile terminal, the expected measurement map being associated with a plurality of communication devices and a plurality of hypothesis locations, wherein receiving the expected measurement map comprises receiving a set of expected measurement values associated with the plurality of communication devices and the plurality of hypothesis locations;

receiving parameters of a matrix corresponding to the expected measurement map;

capturing actual measurements of the one or more parameters for the plurality of communication devices, wherein each of the actual measurements and the expected measurement map comprise values indicative of a delay in a communication path between the mobile terminal and one or more of the plurality of communication devices; and

utilizing the received one or more parameters and actual measurements to estimate a position of the mobile terminal, wherein the instructions for estimating the position of the mobile terminal include instructions for

computing a respective interim vector from the actual measurements and the expected measurement map for each hypothesis location,

computing joint probability distribution values as an exponential of a matrix product using the interim vector and the matrix to produce a joint probability distribution value, and

filtering the joint probability distribution value to estimate the position of the mobile terminal.

20. The device of claim 19, wherein the expected measurement map comprises, for each of a plurality of hypothesis locations (Loc(i,j)), a set of expected measurement values ({right arrow over (μ

)}_Loc(i,j)) containing expected measurements for the parameter, each of the expected measurements corresponding to a respective communication device of the plurality of communication devices.

21. The device of claim 19, wherein the instructions stored on the non-transitory memory further comprise instructions to:

capture measurements ({right arrow over (μ

)}_AT), from the position of the mobile terminal, for each of the plurality of communication devices; and

computing, for a plurality of hypothesis locations, an interim vector ({right arrow over (Y)}_i,j) from the actual measurements and the expected measurement map, and computing a joint probability distribution value (P_i,j) as an exponential of a matrix product of {right arrow over (Y)}_i,j and R_nn, and filtering the joint probability distribution value to estimate the position of the mobile terminal.

22. The device of claim 19, wherein the instructions comprise instructions for removing an unknown antenna gain of the mobile terminal.

23. The method of claim 19, wherein the software instructions comprise instructions for removing an unknown processing delay of the plurality of communication devices.

24. A non-transitory computer-readable storage medium including program code stored thereon, comprising program code for:

receiving an expected measurement map indicative of an expected measurement of one or more parameters by a mobile terminal, the expected measurement map being associated with a plurality of communication devices and a plurality of hypothesis locations, wherein receiving the expected measurement map comprises receiving a set of expected measurement values associated with the plurality of communication devices and the plurality of hypothesis locations;

receiving parameters of a matrix corresponding to the expected measurement map;

capturing, by the mobile terminal, actual measurements of the one or more parameters for the plurality of communication devices, wherein each of the actual measurements and the expected measurement map comprise values indicative of a delay in a communication path between the mobile terminal and one or more of the plurality of communication devices; and

utilizing the received one or more parameters and actual measurements to estimate a position of the mobile terminal, wherein the instructions for estimating the position of the mobile terminal include instructions for

computing a respective interim vector from the actual measurements and the expected measurement map for each hypothesis location,

computing joint probability distribution values as an exponential of a matrix product using the interim vector and the matrix to produce a joint probability distribution value, and

filtering the joint probability distribution value to estimate the position of the mobile terminal.

25. The non-transitory computer-readable storage medium including program code stored thereon of claim 24, further comprising program code for Kalman filtering joint probability distribution values derived for the received parameters and the actual measurements.