Access point, terminal, and wireless fidelity WiFi indoor positioning method

Patent metadata

Field	Value
Publication number	US-9952308-B2
Application number	US-201715410881-A
Country	US
Kind code	B2
Filing date	Jan 20, 2017
Priority date	Jul 22, 2014
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

An access point, a terminal, and a Wireless Fidelity indoor positioning method are provided. The method includes: receiving, by a first access point, a first positioning signal sent by a terminal, and recording a moment for receiving the first positioning signal as a first moment t 1 ; receiving, a second positioning signal sent by an i th second access point in n second access points, and recording a fourth moment t i4 ; sending, a response signal of the second positioning signal to the i th second access point, and recording a fifth moment t i5 ; receiving, a second moment t i2 , a third moment t i3 , and a sixth moment t i6 that are sent by the i th second access point; and determining, location coordinates of the terminal. In the embodiments of the present disclosure, clock synchronization is not required. In addition, terminal positioning accuracy is improved.

First claim

What is claimed is:

1. A first access point comprising:
a receiver configured to:
receive a first positioning signal from a terminal at a first moment t 1 ;
record t 1 ;
receive, at a fourth moment t 4 , a second positioning signal from a second access point; and
record t 4 ;

a transmitter configured to:
transmit, in response to receiving the second positioning signal, a response signal to the second access point at a fifth moment t 5 , and
record t 5 , wherein the receiver is further configured to receive a second moment t 2 indicating when the second access point receives the first positioning signal, a third moment t 3 indicating when the second access point transmits the second positioning signal to the first access point, and a sixth moment t 6 indicating when the second access point receives the response signal; and

a processor coupled to the receiver and the transmitter and configured to:
determine a time difference t d according to t 1 , t 2 , t 3 , t 4 , t 5 , and t 6 , wherein t d indicates a first difference value between a first signal transmission time Δ 1 from the terminal to the first access point and a second signal transmission time Δ 2 from the terminal to the second access point;
determine a distance difference D 0 according to t d , wherein D 0 =C×t d , D 0 indicates a second difference value between a first distance from the terminal to the first access point and a second distance from the terminal to the second access point, and C indicates a velocity of light; and
determine first location (x,y) of the terminal according to the distance difference D 0 , second location coordinates (x 1 , y 1 ) of the first access point, and third location coordinates (x 2 , y 2 ) of the second access point.

2. The first access point of claim 1 , wherein the processor is further configured to:
determine Δ 1 and Δ 2 according to t 1 , t 2 , t 3 , t 4 , t 5 , and t 6 , wherein

Δ
1

=

t
1

-

t
0

,

Δ
2

=

(

t
4

-

t
0

)

-

(

t
3

-

t
2

)

-

Δ
3

,

Δ
3

=

(

t
6

-

t
3

)

-

(

t
5

-

t
4

)

2

,

t 0 indicates a moment at which the terminal sends the first positioning signal, and Δ 3 indicates a third signal transmission time from the second access point to the first access point;
determine t d according to Δ 1 and Δ 2 , wherein

t
d

=

Δ
2

-

Δ
1

=

(

t
4

-

t
1

)

-

(

t
3

-

t
2

)

-

(

t
6

-

t
3

)

-

(

t
5

-

t
4

)

2

;

and
determine (x,y) according to the equation

(

x
2

-
x

)

2

-

Assignees

• Huawei Tech Co Ltd

Inventors

• He Hongkun
• Feng Qianni
• Shi Lei
• Cui Jie
• Li Anjian

Classifications

• G01S5/02216

  Timing or synchronisation of the 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

• H04W52/0206

  in access points, e.g. base stations · CPC title

• G01S5/021

  Calibration, monitoring or correction (G01S5/0252 takes precedence) · CPC title

• G01S5/0081

  Transmission between base stations · CPC title