System and method for computing the location of a mobile terminal in a wireless communications network

US 6,728,545 B1
Filed: 11/16/2001
Issued: 04/27/2004
Est. Priority Date: 11/16/2001
Status: Expired due to Term

First Claim

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1. A method for determining the location of a terminal in a wireless communications network, comprising:

receiving respective signals from each of at least four reference terminals at said terminal, each said respective signal including information representing a location of its respective said reference terminal;

estimating a respective distance from said terminal to each of said reference terminals based on said respective signals received at said terminal;

calculating a respective simulated pattern about each of said respective reference terminals based on said respective estimated distance from said terminal to each said respective reference terminal and said respective locations of said respective reference terminals;

estimating a location at which each of said simulated patterns have the smallest error in their respective estimated distance, and identifying said estimated location as representing the location of said terminal; and

performing error minimizing calculations based on Gauss'"'"'s postulate to minimize sum of square errors in estimating said location.

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Abstract

A system and method for computing the location of a mobile terminal in a wireless communications network, such as an ad-hoc wireless communications network. In particular, the system and method estimates the location of a mobile terminal in a wireless communications network, such as an ad-hoc terrestrial wireless communications network, based on estimated distances to a plurality of terrestrial reference terminals using error minimizing techniques, such as those based on Gauss'"'"'s postulate. In doing so, the system and method estimate a respective distance from the mobile terminal to each of the reference terminals based on the respective signals received at the mobile terminal from the reference terminals, calculate a respective simulated pattern, such as a sphere or circle, about each of the respective reference terminals based on the respective distance from the terminal to each respective reference terminal and the respective locations of the respective reference terminals, estimates a location at which each of the simulated patterns intersect each other, and identifies the estimated location as representing the location of the terminal.

214 Citations

18 Claims

1. A method for determining the location of a terminal in a wireless communications network, comprising:
- receiving respective signals from each of at least four reference terminals at said terminal, each said respective signal including information representing a location of its respective said reference terminal;
  
  estimating a respective distance from said terminal to each of said reference terminals based on said respective signals received at said terminal;
  
  calculating a respective simulated pattern about each of said respective reference terminals based on said respective estimated distance from said terminal to each said respective reference terminal and said respective locations of said respective reference terminals;
  
  estimating a location at which each of said simulated patterns have the smallest error in their respective estimated distance, and identifying said estimated location as representing the location of said terminal; and
  
  performing error minimizing calculations based on Gauss'"'"'s postulate to minimize sum of square errors in estimating said location.
- View Dependent Claims (2, 3, 4, 5)
- - 2. A method as claimed in claim 1, wherein
- 3. A method as claimed in claim 1, wherein said network includes an ad-hoc network, and said terminal and said reference terminals are adapted to operate in said ad-hoc network.
- 4. A method as claimed in claim 1, wherein each of said patterns is spherical.
- 5. A method as claim ed in claim 3, wherein said terminal is a mobile terminal.

6. A system for determining the location of a terminal in a wireless communications network, comprising:
- a receiver, adapted to receive respective signals from each of at least four reference terminals at said terminal, each said respective signal including information representing a location of its respective said reference terminal; and
  
  a processor, adapted to estimate a respective distance from said terminal to each of said reference terminals based on said respective signals received at said terminal, calculate a respective simulated pattern about each of said respective reference terminals based on said respective estimated distance from said terminal to each said respective reference terminal and said respective locations of said respective reference terminals, estimate a location at which each of said simulated patterns have the smallest error in their respective estimated distance, identify said estimated location as representing the location of said terminal, and perform error minimizing calculations based on Gauss'"'"'s postulate to minimize sum of square errors in estimating said location.
- View Dependent Claims (7, 8, 9, 10)
- - 7. A system as claimed in claim 6, wherein
- 8. A system as claimed in claim 6, whereinsaid network includes an ad-hoc network, and said terminal and said reference terminals are adapted to operate in said ad-hoc network.
- 9. A system as claimed in claim 6, whereineach of said patterns is spherical.
- 10. A system as claimed in claim 8, wherein said terminal is a mobile terminal.

11. A computer-readable medium of instructions for determining the location of a terminal in a wireless communications network, comprising:
- a first set of instructions, adapted to estimate a respective distance from said terminal to each of at least four reference terminals based on respective signals received at said terminal from each of a plurality of reference terminals, each said respective signal including information representing a location of its respective said reference terminal;
  
  a second set of instructions, adapted to calculate a respective simulated pattern about each of said respective reference terminals based on said respective estimated distance from said terminal to each said respective reference terminal and said respective locations of said respective reference terminals; and
  
  a third set of instructions, adapted to estimate a location at which each of said simulated patterns have the smallest error in their respective estimated distance, identify said estimated location as representing the location of said terminal, and perform error minimizing calculations based on Gauss'"'"'s postulate to minimize sum of square errors in estimating said location.
- View Dependent Claims (12, 13, 14, 15)
- - 12. A computer-readable medium of instructions as claimed in claim 11, wherein said reference terminals are each terrestrial terminals.
  - 13. A computer-readable medium of instructions as claimed in claim 11, wherein said network includes an ad-hoc network, and said terminal and said reference terminals are adapted to operate in said ad-hoc network.
  - 14. A computer-readable medium of instructions as claimed in claim 11, wherein
- 15. A computer readable medium of instructions as claimed in claim 13, wherein said terminal is a mobile terminal.

16. A method for determining the location of a terminal in a wireless communications network, comprising:
- receiving respective signals from each of a plurality of reference terminals at said terminal, each said respective signal including information representing a location of its respective said reference terminal;
  
  estimating a respective distance from said terminal to each of said reference terminals based on said respective signals received at said terminal;
  
  calculating a respective simulated pattern about each of said respective reference terminals based on said respective estimated distance from said terminal to each said respective reference terminal and said respective locations of said respective reference terminals; and
  
  estimating a location at which each of said simulated patterns have the smallest error in their respective estimated distance, and identifying said estimated location as representing the location of said terminal;
  
  wherein the smallest error is determined in the location estimating step based on the following equations;
  
  ${\begin{matrix} \sum_{i = 1}^{n} (\frac{r_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})} ({(\frac{x_{0} - x_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})})}^{2} - 1) + 1) δ x + \sum_{i = 1}^{n} (\frac{(x_{0} - x_{i}) (y_{0} - y_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ y + \sum_{i = 1}^{n} (\frac{(x_{0} - x_{i}) (z_{0} - z_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ z = - \sum_{i = 1}^{n} ((ρ_{i} (x_{0}, y_{0}, z_{0}) - r_{i}) \frac{x_{0} - x_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})}) \\ \sum_{i = 1}^{n} (\frac{(y_{0} - y_{i}) (x_{0} - x_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ x + \sum_{i = 1}^{n} (\frac{r_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})} ({(\frac{y_{0} - y_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})})}^{2} - 1) + 1) δ y + \sum_{i = 1}^{n} (\frac{(y_{0} - y_{i}) (z_{0} - z_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ z = - \sum_{i = 1}^{n} ((ρ_{i} (x_{0}, y_{0}, z_{0}) - r_{i}) \frac{y_{0} - y_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})}) \\ \sum_{i = 1}^{n} (\frac{(z_{0} - z_{i}) (x_{0} - x_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ x + \sum_{i = 1}^{n} (\frac{(z_{0} - z_{i}) (y_{0} - y_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ y + \sum_{i = 1}^{n} (\frac{r_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})} ({(\frac{z_{0} - z_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})})}^{2} - 1) + 1) δ z = - \sum_{i = 1}^{n} ((ρ_{i} (x_{0}, y_{0}, z_{0}) - r_{i}) \frac{z_{0} - z_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})}) \end{matrix}$ where three unknown variables δ
  
  x, δ
  
  y, δ
  
  z, represent corrections to be applied to an estimation of the location of said terminal represented by coordinates (x₀, y₀, z₀).

17. A system for determining the location of a terminal in a wireless communications network, comprising:
- a receiver, adapted to receive respective signals from each of a plurality of reference terminals at said terminal, each said respective signal including information representing a location of its respective said reference terminal; and
  
  a processor, adapted to estimate a respective distance from said terminal to each of said reference terminals based on said respective signals received at said terminal, calculate a respective simulated pattern about each of said respective reference terminals based on said respective estimated distance from said terminal to each said respective reference terminal and said respective locations of said respective reference terminals, estimate a location at which each of said simulated patterns have the smallest error in their respective estimated distance, and identify said estimated location as representing the location of said terminal;
  
  wherein the smallest error is determined in the location estimating based on the following equations;
  
  ${\begin{matrix} \sum_{i = 1}^{n} (\frac{r_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})} ({(\frac{x_{0} - x_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})})}^{2} - 1) + 1) δ x + \sum_{i = 1}^{n} (\frac{(x_{0} - x_{i}) (y_{0} - y_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ y + \sum_{i = 1}^{n} (\frac{(x_{0} - x_{i}) (z_{0} - z_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ z = - \sum_{i = 1}^{n} ((ρ_{i} (x_{0}, y_{0}, z_{0}) - r_{i}) \frac{x_{0} - x_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})}) \\ \sum_{i = 1}^{n} (\frac{(y_{0} - y_{i}) (x_{0} - x_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ x + \sum_{i = 1}^{n} (\frac{r_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})} ({(\frac{y_{0} - y_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})})}^{2} - 1) + 1) δ y + \sum_{i = 1}^{n} (\frac{(y_{0} - y_{i}) (z_{0} - z_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ z = - \sum_{i = 1}^{n} ((ρ_{i} (x_{0}, y_{0}, z_{0}) - r_{i}) \frac{y_{0} - y_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})}) \\ \sum_{i = 1}^{n} (\frac{(z_{0} - z_{i}) (x_{0} - x_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ x + \sum_{i = 1}^{n} (\frac{(z_{0} - z_{i}) (y_{0} - y_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ y + \sum_{i = 1}^{n} (\frac{r_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})} ({(\frac{z_{0} - z_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})})}^{2} - 1) + 1) δ z = - \sum_{i = 1}^{n} ((ρ_{i} (x_{0}, y_{0}, z_{0}) - r_{i}) \frac{z_{0} - z_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})}) \end{matrix}$ where three unknown variables δ
  
  x, δ
  
  y, δ
  
  z, represent corrections to be applied to an estimation of the location of said terminal represented by coordinates (x₀, y₀, z₀).

18. A computer readable medium of instructions for determining the location of a terminal in a wireless communications network, comprising:
- a first set of instructions, adapted to estimate a respective distance from said terminal to each of a plurality of reference terminals based on respective signals received at said terminal from each of a plurality of reference terminals, each said respective signal including information representing a location of its respective said reference terminal;
  
  a second set of instructions, adapted to calculate a respective simulated pattern about each of said respective reference terminals based on said respective estimated distance from said terminal to each said respective reference terminal and said respective locations of said respective reference terminals; and
  
  a third set of instructions, adapted to estimate a location at which each of said simulated patterns have the smallest error in their respective estimated distance, and identifying said estimated location as representing the location of said terminal;
  
  wherein the smallest error is determined in the location estimating based on the following equations;
  
  ${\begin{matrix} \sum_{i = 1}^{n} (\frac{r_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})} ({(\frac{x_{0} - x_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})})}^{2} - 1) + 1) δ x + \sum_{i = 1}^{n} (\frac{(x_{0} - x_{i}) (y_{0} - y_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ y + \sum_{i = 1}^{n} (\frac{(x_{0} - x_{i}) (z_{0} - z_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ z = - \sum_{i = 1}^{n} ((ρ_{i} (x_{0}, y_{0}, z_{0}) - r_{i}) \frac{x_{0} - x_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})}) \\ \sum_{i = 1}^{n} (\frac{(y_{0} - y_{i}) (x_{0} - x_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ x + \sum_{i = 1}^{n} (\frac{r_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})} ({(\frac{y_{0} - y_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})})}^{2} - 1) + 1) δ y + \sum_{i = 1}^{n} (\frac{(y_{0} - y_{i}) (z_{0} - z_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ z = - \sum_{i = 1}^{n} ((ρ_{i} (x_{0}, y_{0}, z_{0}) - r_{i}) \frac{y_{0} - y_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})}) \\ \sum_{i = 1}^{n} (\frac{(z_{0} - z_{i}) (x_{0} - x_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ x + \sum_{i = 1}^{n} (\frac{(z_{0} - z_{i}) (y_{0} - y_{i}) r_{i}}{ρ_{i}^{3} (x_{0}, y_{0}, z_{0})}) δ y + \sum_{i = 1}^{n} (\frac{r_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})} ({(\frac{z_{0} - z_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})})}^{2} - 1) + 1) δ z = - \sum_{i = 1}^{n} ((ρ_{i} (x_{0}, y_{0}, z_{0}) - r_{i}) \frac{z_{0} - z_{i}}{ρ_{i} (x_{0}, y_{0}, z_{0})}) \end{matrix}$ where three unknown variables δ
  
  x, δ
  
  y, δ
  
  z, represent corrections to be applied to an estimation of the location of said terminal represented by coordinates (x₀, y₀, z₀).

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Current Assignee
ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
Original Assignee
MeshNetworks, Inc. (Motorola Solutions, Inc.)
Inventors
Belcea, John M.
Primary Examiner(s)
Tran, Sinh
Assistant Examiner(s)
Afshar, Kamran

Application Number

US09/988,001
Time in Patent Office

893 Days
Field of Search

455/456.1, 455/2, 455/517, 455/561, 455/457, 455/524, 455/525, 455/676, 455/404.2, 455/422, 455/41.1, 455/41.2, 455/41.3, 370/241, 370/252, 370/331, 370/332, 370/333, 370/254, 370/347, 370/342, 370/441, 370/442, 342/457, 342/463, 342/357.06, 342/453, 342/454
US Class Current

455/456.2
CPC Class Codes

G01S 5/0284   Relative positioning

G01S 5/0289   of multiple transceivers, e...

G01S 5/14   Determining absolute distan...

H04W 64/00   Locating users or terminals...

System and method for computing the location of a mobile terminal in a wireless communications network

First Claim

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Abstract

214 Citations

18 Claims

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System and method for computing the location of a mobile terminal in a wireless communications network

First Claim

8 Assignments

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Accused Products

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Abstract

214 Citations

18 Claims

Specification

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