WIRELESS LOCATION DETERMINATION SYSTEM AND METHOD

• US 20110051608A1
• Filed: 11/30/2009
• Published: 03/03/2011
• Est. Priority Date: 08/25/2009
• Status: Active Grant

• Current Assignee: Korea Electrotechnology Research Institute
• Original Assignee: Korea Electrotechnology Research Institute
• Inventors: Lee, Soon Woo, Kang, Ji Myung, Kim, Kwan Ho, Park, Young Jin
• Granted Patent: US 8,340,022 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Disclosed herein is a wireless location determination system and method.

A wireless location determination system of the present invention includes one or more location determination nodes (reception units) for calculating standard deviations of time intervals between pulses sequentially received from a location determination target, and estimating reliability values from the standard deviations. A location determination server receives messages, including the reliability values, from the location determination nodes, and obtains a location of the location determination target (transmission unit). Accordingly, the present invention can not only improve the resolution of location determination by correcting the distances between the location determination target and the respective location determination nodes, but also can easily observe the location determination performance of a relevant node by monitoring reliability values of the location determination nodes, and can regard the reliability values as measures for the observation of performance and the maintenance of location determination nodes.

Claims

1. A wireless location determination system, comprising:

a tag which is a location determination target for generating and transmitting a plurality of pulses at regular time intervals;

one or more nodes for sequentially receiving the pulses transmitted from the tag, calculating standard deviations of time intervals between the pulses received by the respective nodes and computing reliability values based on the standard deviations; and

a location determination server for receiving messages including the reliability values from the respective nodes, and obtaining a location of the tag.

2. The wireless location determination system according to claim 1, wherein the reliability values are calculated by the following equation:

t(Node_k)=1/σ

(Node_k)

where t(Node_k) is a reliability value of node k, and σ

(Node_k) is a standard deviation of time intervals between pulses received by the node k.

3. The wireless location determination system according to claim 1, wherein the location determination server calculates distances between the location determination target and the respective nodes from times of arrival of initial pulses at the nodes, which are included in the respective messages, and obtains the location of the location determination target by applying the reliability values to the calculated distances.

4. The wireless location determination system according to claim 3, wherein the location determination server calculates the distances between the location determination target and the respective nodes through a Time Of Arrival (TOA) scheme or a Time Difference Of Arrival (TDOA) scheme.

5. The wireless location determination system according to claim 1, wherein the location determination server computes ranges of standard deviations that can be calculated in a normal operation state of the respective nodes, and determines that an abnormality has occurred in a relevant node when a standard deviation received from the relevant node deviates from a corresponding computed range.

6. A wireless location determination method, comprising:

a first step of sequentially receiving a plurality of pulses that are transmitted from a location determination target at regular time intervals; and

a second step of calculating standard deviations of time intervals between the received pulses and computing reliability values from the standard deviations,

wherein a location of the location determination target is obtained by applying the reliability values to estimated distances to the location determination target.

7. The wireless location determination method according to claim 6, further comprising, after the second step, a third step of calculating the estimated distances to the location determination target using times of arrival of the received pulses, and applying the reliability values to the estimated distances, thus estimating the location of the location determination target.