Localizing a target device based on measurements from a measurement device array

Patent metadata

Field	Value
Publication number	US-11353541-B2
Application number	US-202017283400-A
Country	US
Kind code	B2
Filing date	Jun 3, 2020
Priority date	Jun 3, 2020
Publication date	Jun 7, 2022
Grant date	Jun 7, 2022

Abstract

In a general aspect, a target is localized based on measurements from a measurement device array. In some aspects, range difference values (di) and coordinate vectors (ai) of devices in the measurement device array are obtained. The range difference values are generated based on time difference of arrival measurements of wireless signals between the target device and each of the devices in the measurement device array. A first matrix (A) and a first vector (b) are constructed. The first matrix (A) and the first vector (b) each includes the range difference values and the coordinate vectors. Whether a second vector (y) satisfies a condition set is determined. The condition set includes a first condition (ATA+λD)y=ATb and a second condition vT (ATA+λD)v≥0. A numerical approximation of an optimal solution of the second vector is generated. The target device is localized according to the numerical approximation of the optimal solution.

First claim

What is claimed is:

1. A localization method for localizing a target device using a measurement device array, the method comprising:
obtaining range difference values (d i ) and coordinate vectors ( a i ) of devices in the measurement device array, wherein the range difference values are generated based on time difference of arrival measurements of wireless signals between the target device and each of the devices in the measurement device array;
constructing a first matrix (A), a first vector (b), and a second vector (y), the first matrix (A) and the first vector (b) each comprising the range difference values and the coordinate vectors, wherein the first matrix

A
=

[

d
1

a
1
T

_

⋮

⋮

d
m

a
_

m
T

]

,

the first vector

b
=

1
2

⁡

[



a
1

_



2

-

d
1
2

⋮



a
_

m



2

-

d
m
2

]

,

the second vector y=[∥ x ∥, x T ] T , i is a positive integer, and i=1, m, x is a coordinate vector of the target device, and a number of the devices in the measurement device array equals m+1;
identifying a condition set, the condition set comprising: a first condition (A T A+λD)y=A T b and a second condition v T (A T A+λD)v≥0 for all third vectors (v) satisfying v T Dv≤0, wherein a second matrix

D
=

[

1

0

1
×
n

0

n
×
1

-

I
n

]

and λ is a Lagrange multiplier;
determining whether the second vector (y) satisfies the condition set;
generating a numerical approximation of an optimal solution of the second vector (y) based on a result of determining whether the second vector (y) satisfies the condition set; and
localizing the target device according to the numerical approximation of the optimal solution.

2. The localization method of claim 1 , wherein the number of the devices in the measurement device array is equal to or greater than four.

3. The localization method of claim 1 , wherein determining whether the second vector (y) satisfies the condition set further comprises:
determining a solution Lagrange multiplier (λ*) based on a result of determining whether the Lagrange multiplier (λ) satisfies the condition set; and
determining whether the second vector (y) satisfies a constraint set, the constraint set comprising a first constraint g(y)=y T Dy=0 and a second constraint [y] 1 ≥0, wherein [y] 1 is the first element of the second vector (y).

4. The localization method of claim 3 , further comprising:
in response to the second vector (y) not satisfying at least one of the first constraint, the second constraint, the first condition or the second condition, localizing the target device according to the optimal solution, wherein the optimal solution equals zero.

5. The localization method of claim 3 , wherein determining the solution Lagrange multiplier comprises:
performing a first search of the solution Lagrange multiplier in a first domain; and
in response to the solution Lagrange multiplier being not determined in the first domain, performing a second search of the solution Lagrange multiplier in a second domain.

6. The localization method of claim 5 , wherein determining the solution Lagrange multiplier further comprises:
prior to performing the first sea

Assignees

• Univ Zhejiang

Inventors

• Wu Junfeng
• Chen Jiming
• Wei Jieqiang
• Zeng Guangyang

Classifications

• G01S5/0221

  Receivers · CPC title

• G01S5/06 Primary

  Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements (G01S5/12 takes precedence) · CPC title

• H04W64/00

  Locating users or terminals {or network equipment} for network management purposes, e.g. mobility management · CPC title

• G01S5/0205

  Details · CPC title