Apparatus and method for RSS/AoA target 3-D localization in wireless networks

• US 10,338,193 B2
• Filed: 10/07/2016
• Issued: 07/02/2019
• Est. Priority Date: 10/07/2016
• Status: Active Grant

• Current Assignee: Marko Beko
• Original Assignee: Marko Beko
• Inventors: Beko, Marko, Tomic, Slavisa, Dinis, Rui, Carvalho, Paulo
• Primary Examiner(s): Olson, Jason C
• Application Number:
  US15/287,880
• Publication Number:
  US 20180100915A1
• Time in Patent Office: 998 Days
• Field of Search: 4554561
• CPC Class Codes: G01S 5/02213 Receivers arranged in a network for determining the position of a transmitter
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial

Abstract

An apparatus and a method for RSS/AoA target 3-D localization in wireless networks and wireless sensor networks (WSNs), utilizing combined measurements of received signal strength (RSS) and angle of arrival (AoA) are disclosed herein. By using the spherical coordinate conversion and available AoA observations to establish new relationships between the measurements and the unknown target location, a simple closed-form solution is developed. The method disclosed herein has a straightforward adaptation to the case where the target'"'"'s transmit power is also not known. A representative set of simulations and experiments verify the potential performance improvement realized with embodiments of the method for RSS/AoA target 3-D localization in wireless networks.

Claims

1. An apparatus for target localization in wireless networks comprising:

M targets and N anchor receivers, wherein each anchor receiver includes at least one directive or antenna array to receive a signal sent from a target;

a processing unit configured to receive the RSS (received signal strength) information form said receivers and to process the RSS information and to compute a distance measurement between said targets and said receivers;

a processing unit configured to receive AoA (angle of arrival) information from said receivers, wherein the AOA information includes angles of azimuth and elevation measurements of the incoming signal transmitted by each one of the targets present in the wireless network;

a processing unit configured to compute a conversion from Cartesian coordinates of the RSS and AOA information to spherical coordinates in order to merge the RSS and AoA information; and

an estimator configured to estimate a location of each target based on the merged RSS and AoA information and WLS (weighted least squares) criterion, wherein the WLS criterion determines weights based on a ML (maximum likelihood) estimate of the distance measurement.

2. A method for target localization in wireless networks with M targets and N anchors receivers, wherein each anchor receiver includes at least one directive or antenna array to receive a signal sent from a target comprising the following steps:

receive RSS (received signal strength) information form said receivers and process the RSS information to compute a distance measurement between said targets and said receivers;

receive AoA (angle of arrival) information from said receivers, wherein the AOA information includes angles of azimuth and elevation measurements of the incoming signal transmitted by each one of the targets present in the wireless network;

compute a conversion from Cartesian coordinates of the RSS and AoA information to spherical coordinates in order to merge the RSS and AoA information; and

estimate a location of each target based on the merged RSS and AoA information and WLS (weighted least squares) criterion, wherein the WLS criterion determines weights based on a ML (maximum likelihood) estimate of the distance measurement.

3. The method of claim 2, when transmitted power information P_T of each target is known, comprising the following steps:

a. define and compute the following relations;

λ

_i∥

x−

a_i∥

≈

η

d₀ for i=1, . . . ,N, 

 

(7)

c_i^T(x−

a_i)≈

0, for i=1, . . . ,N, 

 

(8)

k^T(x−

a_i)≈

∥

x−

a_i∥

cos(α

_i), for i=1, . . . ,N, 

 

(9)

 

where

4. The method of claim 2, when the transmitted power information P_T of each target is unknown, comprising the following steps:

a. first, define and compute the following relations;

λ

_i∥

x−

a_i∥

≈

η

d₀ for i=1, . . . ,N, 

 

(7)

c_i^T(x−

a_i)≈

0m for i=1, . . . ,N, 

 

(8)

k^T(x−

a_i)≈

∥

x−

a_i∥

cos(α

_i), for i=1, . . . ,N, 

 

(9)

 

where