Method and system for estimating the position of a mobile device

• US 7,751,827 B2
• Filed: 09/06/2002
• Issued: 07/06/2010
• Est. Priority Date: 09/06/2002
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Nokia Corporation
• Inventors: Spirito, Maurizio, Poykko, Sami
• Primary Examiner(s): Eng, George
• Assistant Examiner(s): HUYNH, NAM TRUNG
• Application Number:
  US10/526,400
• Publication Number:
  US 20050267677A1
• Time in Patent Office: 2,860 Days
• Field of Search: 4554561-457, 455/403, 342/357.1
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/02521 using a radio-map
• CPC Class Codes: G01S 5/0263 by combining or switching between positions derived from two or more separate positioning systems
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method of estimating the location of a mobile device, comprising the steps of: collecting location information; selecting at least one of a plurality of different location methods to provide a location estimate; and providing a location estimate based on the at least one selected location method.

Claims

1. A method, comprising:

collecting location information;

selecting at least one of a plurality of different location methods to provide a location estimate said methods comprising using cell identity information;

determining a first location estimate of a mobile device based on the at least one selected location method, said first location estimate being based on a serving base transceiver station;

determining a virtual base station estimate using at least some of the collected location information, said virtual base station estimate being determined based on the first location estimate of the mobile device and direction information of the serving base transceiver station; and

providing a second location estimate using one of said different location methods based on the first location estimate and the virtual base station estimate, said second location estimate being a location of the mobile device.

2. A method as claimed in claim 1, wherein said at least one location method comprises at least one of:

using cell identity information;

using cell identity information and received signal strength;

using cell identity information and timing advance information; and

using cell identity information, received signal strength information and timing advance information.

3. A method as claimed in claim 2, further comprising determining the virtual base station estimate, using at least one of the cell identity information, cell identity information and received signal strength, cell identity information and timing advance information, and using cell identity information, received signal strength information and timing advance information.

4. A method as claimed in claim 1, wherein said virtual base station location estimate is coupled with at least one virtual measurement and at least one real measurement, said at least one virtual measurement being processed using a location method.

5. A method as claimed in claim 2, wherein providing said second location estimate comprises processing said virtual base station location estimate is coupled with at least one virtual measurement and at least one real measurement, said at least one virtual measurement being processed using a location method, and wherein the at least one real and the at least one virtual measurements are processed using at least one of cell identity information, cell identity information and received signal strength, cell identity information and timing advance information, and using cell identity information, received signal strength information and timing advance information.

6. A method as claimed in claim 4, wherein a value for the virtual measurement is one of measured levels, a combination of measured levels, and an average of measured levels.

7. A method as claimed in claim 1, wherein said at least one location method is selected in dependence on the location information available.

8. A method as claimed in claim 1, wherein a plurality of location estimates are determined and at least one estimate is used to provide said location estimate.

9. A method as claimed in claim 1, wherein said location information is collected by said mobile device.

10. A method as claimed in claim 9, wherein said mobile device is configured to measure a level of at least one type of information.

11. A method as claimed in claim 1, wherein said location information comprises at least one of timing advance information and received signal level.

12. A method as claimed in claim 11, wherein said received signal level is an absolute received signal level or relative received signal level.

13. A method as claimed in claim 1, wherein said mobile device is in a cellular communications device.

14. A method as claimed in claim 13, wherein said information is collected for a serving cell of the mobile device.

15. A method as claimed in claim 13, wherein said information is collected for at least one neighbouring cell.

16. A method as claimed in claim 13, further comprising selecting the or each cell in respect of which location information is collected.

23. A method as claimed in claim 1, wherein said location estimate is provided by one of a iterative and a closed form method.

24. A method as claimed in claim 1, wherein said location estimate is provided by one of a linear and non linear method.

17. A method, comprising:

collecting location information;

selecting at least one of a plurality of different location methods to provide a location estimate said methods comprising using cell identity information;

providing a location estimate of the mobile device based on the at least one selected location methods,

wherein the location estimate is provided using the following algorithm

calculate the total attenuation experienced by a signal transmitted by the i-th BTS while propagating toward a mobile station where i-th level observation is Lⁱ) by subtracting from the i-th measured received power, Pⁱ_r, the maximum power radiated by the i-th BTS, Pⁱ_t,max;

Lⁱ=P_rⁱ−

P_t,maxⁱ;

i=1, . . . ,N

stack the level observations from N BTS'"'"'s in vector L;

L=[L¹, . . . ,L^N]^T

solve the minimization problem;

$\left[\begin{array}{c}{\widehat{\mathrm{\sigma <br><br>}}}_u^2\\ \hat{x}\\ \hat{y}\end{array}\right]=\arg <br><br><br><br>\underset{\left[\begin{array}{c}{\mathrm{\sigma <br><br>}}_u^2\\ x\\ y\end{array}\right]}{\min }<br><br>F<br><br>\left(x,y;<br><br>{\mathrm{\sigma <br><br>}}_u^2\right)$

where the cost function F (x,y;

σ

_u²) is defined as follows;

$\begin{array}{cc}F<br><br>\left(x,y;<br><br>{\mathrm{\sigma <br><br>}}_u^2\right)=\ln <br><br><br><br>{\mathrm{\sigma <br><br>}}_u^2+\ln <br><br><br><br>r_L<br><br>\left(x,y\right)<br><br>+{\frac{1}{{\mathrm{\sigma <br><br>}}_u^2}<br><br>\left[L-m_L<br><br>\left(x,y\right)\right]}^T<br><br>r_L^{-1}<br><br>\left(x,y\right)<br><br>\left[L-m_L<br><br>\left(x,y\right)\right]<br><br><br><br>\mathrm{and}& \\ <br><br>m_L<br><br>\left(x,y\right)={\left[{\mathrm{\mu <br><br>}}_L^1<br><br>\left(x,y\right),\mathrm{\dots <br><br>}<br><br>,{\mathrm{\mu <br><br>}}_L^N<br><br>\left(x,y\right)\right]}^T& \\ <br><br>{\mathrm{\mu <br><br>}}_L^i<br><br>\left(x,y\right)=-{\mathrm{PL}}^i<br><br>\left(d^i<br><br>\left(x,y\right)\right)-{\mathrm{AP}}_{\mathrm{tr}}^i<br><br>\left({\mathrm{\psi <br><br>}}^i<br><br>\left(x,y\right)\right)& \\ <br><br>{\left[r_L<br><br>\left(x,y\right)\right]}_{\mathrm{ij}}=\{\begin{array}{cc}1& i=j\\ {\mathrm{\rho <br><br>}}_u^{i,j}<br><br>\left(x,y\right)& i\ne <br><br>j\end{array}<br><br><br><br>i,j=1,\mathrm{\dots <br><br>}<br><br>,N,& \end{array}$

determining the location of a mobile device dependent on the location estimate.

18. A method, comprising:

collecting location information;

selecting at least one of a plurality of different location methods to provide a location estimate said methods comprising using cell identity information; and

providing a location estimate based on the at least one selected location method, wherein a location estimate is provided using the following algorithm

calculate the total attenuation experienced by a signal transmitted by the i-th BTS while propagating toward a mobile station where the i-th level observation is Lⁱ by subtracting from the i-th measured received power, Pⁱ_r, the maximum power radiated by the i-th BTS, Pⁱ_t,max;

Lⁱ=P_rⁱ−

P_t,maxⁱ;

i=1, . . . ,N

stack level observations from N BTS'"'"'s in vector L;

L=[L¹, . . . ,L^N]^T

solve the minimization problem;

$\begin{array}{cc}\left[\begin{array}{c}\hat{x}\\ \hat{y}\end{array}\right]=\arg <br><br><br><br>\underset{\left[\begin{array}{c}x\\ y\end{array}\right]<br><br>\mathrm{\epsilon <br><br>}<br><br><br><br>D_{\mathrm{xy}}}{\min }<br><br>F<br><br>\left(x,y\right)& \end{array}$

where the cost function F(x,y) is defined as follows;

$\begin{array}{cc}F<br><br>\left(x,y\right)=\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>{\left(L^i+{\mathrm{PL}}^i<br><br>\left(x,y\right)+{\mathrm{AP}}_{\mathrm{tr}}^i<br><br>\left(x,y\right)\right)}^2& \end{array}$

and D_xy is the domain of existence of x and y/

calculate {circumflex over (σ

)}_u² as

{circumflex over (σ

)}_u²=F({circumflex over (x)},ŷ

)

determining the location of a mobile device dependent on the location estimate.

19. A method, comprising:

collecting location information;

selecting at least one of a plurality of different location methods to provide a location estimate said methods comprising using cell identity information; and

providing a location estimate based on the at least one selected location method,

wherein a location estimate is provided using the following algorithm;

calculate the total attenuation experienced by a signal transmitted by the i-th BTS while propagating toward a mobile station where the i-th level observation is Lⁱ) by subtracting from the i-th measured received power, Pt, the maximum power radiated by the i-th BTS, Pⁱ_t,max;

Lⁱ=P_rⁱ−

P_t,maxⁱ;

i=1, . . . ,N

calculate the j-th level difference observation by subtracting the j-th level observation from the level observation L¹ taken as reference;

D^j=L¹−

L^j;

j=2, . . . ,N

stack the N-1 difference of level observations in a vector D;

D=[D², . . . ,D^N]^T

solve the minimization problem

$\begin{array}{cc}<br><br>\left[\begin{array}{c}\hat{x}\\ \hat{y}\end{array}\right]=\arg <br><br><br><br>\underset{\left[\begin{array}{c}x\\ y\end{array}\right]<br><br>\mathrm{\epsilon <br><br>}<br><br><br><br>D_{\mathrm{xy}}}{\min }<br><br>F<br><br>\left(x,y\right)<br><br><br><br>\mathrm{where}& \\ <br><br>F<br><br>\left(x,y\right)=\underset{j=2}{\overset{N}{\sum <br><br>}}<br><br>{\left(D^j-{\mathrm{\mu <br><br>}}_D^j<br><br>\left(x,y\right)\right)}^2-\frac{1}{N}<br><br>{\left(\underset{j=2}{\overset{N}{\sum <br><br>}}<br><br>D^j-{\mathrm{\mu <br><br>}}_D^j<br><br>\left(x,y\right)\right)}^2<br><br><br><br>\mathrm{and}& \\ {\mathrm{\mu <br><br>}}_D^j<br><br>\left(x,y\right)=-\left[{\mathrm{PL}}^1<br><br>\left(d^1<br><br>\left(x,y\right)\right)-{\mathrm{PL}}^j<br><br>\left(d^j<br><br>\left(x,y\right)\right)\right]-\left[{\mathrm{AP}}_{\mathrm{tr}}^1<br><br>\left({\mathrm{\psi <br><br>}}^1<br><br>\left(x,y\right)\right)-{\mathrm{AP}}_{\mathrm{tr}}^j<br><br>\left({\mathrm{\psi <br><br>}}^j<br><br>\left(x,y\right)\right)\right]& \end{array}$

D_xy is the domain of existence of x and y,

determining the location of the mobile device dependent on the location estimate.

20. A method, comprising:

collecting location information;

selecting at least one of a plurality of different location methods to provide a location estimate said methods comprising using cell identity information; and

providing a location estimate based on the at least one selected location method,

wherein a location estimate is provided using an algorithm solving the following equation in x and y;

$\{\begin{array}{c}\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>F^i<br><br>\left(x,y\right)<br><br>\left(x-x^i\right)=0\\ \underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>F^i<br><br>\left(x,y\right)<br><br>\left(y-y^i\right)=0\end{array};<br><br>\left(x,y\right)\in <br><br>\mathrm{??}<br><br><br><br>\mathrm{where}<br><br><br><br>F^i<br><br>\left(x,y\right)=\frac{2<br><br>B^i/C^i<br><br>\left(d_0\right)}{{\left(2<br><br>\mathrm{\pi <br><br>}\right)}^{3/2}<br><br>{\mathrm{\sigma <br><br>}}_u^i<br><br>\ln <br><br><br><br>10}<br><br><br><br><br><br>\frac{\exp <br><br>\left\{-\frac{1}{2<br><br>{\mathrm{\sigma <br><br>}}_u^{i^2}<br><br>}<br><br>{\left(B^i<br><br>{\log }_{10}<br><br>d^i<br><br>\left(x,y\right)-z^i+A^i\right)}^2\right\}}{{\left[d^i<br><br>\left(x,y\right)\right]}^4}·<br><br><br><br><br><br>\left[\frac{B^i<br><br>\left(B^i<br><br>{\log }_{10}<br><br>d^i<br><br>\left(x,y\right)-z^i+A^i\right)}{2<br><br>{\mathrm{\sigma <br><br>}}_u^{i^2}<br><br>\ln <br><br><br><br>10}-1\right],$

determining the location of a mobile device dependent on the location estimate.

21. A method, comprising:

collecting location information;

selecting at least one of a plurality of different location methods to provide a location estimate said methods comprising using cell identity information; and

providing a location estimate based on the at least one selected location method,

wherein a location estimate is provided using an algorithm solving the following equation in x and y;

$\{\begin{array}{c}\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>\left[-\frac{{\mathrm{ℐ<br><br>}}_i}{<br><br>\mathrm{\Re <br><br>}<br><br>}<br><br>\left(x-x^i\right)-\frac{\left({\widetilde{\mathrm{ℐ<br><br>}}}_i-1\right)}{<br><br>\mathrm{\Re <br><br>}<br><br>}<br><br>\left\{{\left(x^i\right)}^2<br><br>x-x^i<br><br>y^i<br><br>\left(y-y^i\right)\right\}\right]=0\\ \underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>\left[-\frac{{\mathrm{ℐ<br><br>}}_i}{<br><br>\mathrm{\Re <br><br>}<br><br>}<br><br>\left(y-y^i\right)-\frac{\left({\widetilde{\mathrm{ℐ<br><br>}}}_i-1\right)}{<br><br>\mathrm{\Re <br><br>}<br><br>}<br><br>\left\{{\left(y^i\right)}^2<br><br>y-x^i<br><br>y^i<br><br>\left(x-x^i\right)\right\}\right]=0\end{array};<br><br><br><br>\left(x,y\right)\in <br><br>\mathrm{??},$

determining the location of a mobile device dependent on the location estimate.

22. A method, comprising:

collecting location information;

selecting at least one of a plurality of different location methods to provide a location estimate said methods comprising using cell identity information; and

providing a location estimate based on the at least one selected location method,

wherein a location estimate is provided using an algorithm based on the following equation in x and y;

$\hat{x}=\frac{\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>\frac{x^i}{{\mathrm{ℐ<br><br>}}_{\mathrm{i0}}}}{\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>\frac{1}{{\mathrm{ℐ<br><br>}}_{\mathrm{i0}}}};<br><br>\hat{y}=\frac{\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>\frac{y^i}{{\mathrm{ℐ<br><br>}}_{\mathrm{i0}}}}{\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>\frac{1}{{\mathrm{ℐ<br><br>}}_{\mathrm{i0}}}};<br><br>\left(\hat{x},\hat{y}\right)\in <br><br>\mathrm{??},$

determining the location of a mobile device dependent on the location estimate.

25. A system, comprising:

collecting means for collecting location information;

selecting means for selecting at least one of a plurality of different location methods to provide a location estimate said methods using cell identity information;

location determining means for determining a first location estimate of a mobile device based on the at least one selected location method, said first location estimate being based on a serving base transceiver station; and

estimate determining means for determining a virtual base station estimate, using one of said different location methods, said virtual base station estimate being determined based on the first location estimate of the mobile device and direction information of the serving base transceiver station; and

providing means for providing a second location estimate based on at least one of the first location estimate and the virtual base station estimate, said second location estimate being an estimate of the location of the mobile device.

26. A system, comprising:

a collector configured to collect location information;

a selector configured to select at least one of a plurality of different location methods to provide a location estimate, said methods using cell identity information;

a determiner configured to determine a first location estimate of a mobile device based on the at least one selected location method, said first location estimate being based on a serving base transceiver station, and further configured to determine a virtual base station estimate using at least some of the collected location information, said virtual base station estimate being determined based on the first location estimate of the mobile device and direction information of the serving base transceiver station; and

a provider configured to provide a second location estimate, using one of said different location methods based on the first location estimate and the virtual base station estimate, said second location estimate being an estimate of the location of the mobile device.

27. Apparatus, comprising:

a collector configured to collect location information;

a selector configured to select at least one of a plurality of different location methods to provide a location estimate, said methods using cell identity information;

a determiner configured to determine a first location estimate of the apparatus based on the at least one selected location method, said first location estimate being based on a serving base transceiver station and further configured to determine a virtual base station estimate based on the first location estimate of the apparatus and direction information of the serving base transceiver station; and

a provider configured to provide a second location estimate, using one of said different location methods based on the first estimate and the virtual base station estimate, said second location estimate being an estimate of the location of the apparatus.

28. A computer program embodied on a computer readable medium, said computer program configured to control a processor to perform:

collecting location information;

selecting at least one of a plurality of different location methods to provide a location estimate said location methods comprising using cell identity information;

determining a first location estimate of a mobile device based on the at least one selected location method, said first location estimate being based on a serving base transceiver station;

determining a virtual base station estimate using at least some of the collected location information, said virtual base station estimate being determined based on the first location estimate of the mobile device and direction information of the serving base transceiver station; and

providing a second location estimate using one of said different location methods based on the first location estimate and the virtual base station estimate, said second location estimate being a location of the mobile device.