Wireless tracking system and method utilizing multiple location algorithms

• US 8,457,656 B2
• Filed: 09/23/2011
• Issued: 06/04/2013
• Est. Priority Date: 09/27/2010
• Status: Active Grant

• Current Assignee: Centrak Incorporated (Halma PLC)
• Original Assignee: Awarepoint Corporation
• Inventors: Perkins, Matthew R., Geng, Wei
• Primary Examiner(s): DOAN, KIET M
• Application Number:
  US13/244,257
• Publication Number:
  US 20120077514A1
• Time in Patent Office: 620 Days
• Field of Search: 455/456.1, 455/434, 455/140, 455/414.2, 455/7, 340/686.6, 340/539.26, 340/8.1, 340/10.1, 340/572.1, 340/539.12, 342/464, 204/403.01
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/0258 by combining or switching between measurements derived from different systems
• CPC Class Codes: G01S 5/0268 by deriving positions from different combinations of signals or of estimated positions in a single positioning system
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves
• CPC Class Codes: G01S 5/18 using ultrasonic, sonic, or infrasonic waves

Abstract

The present invention provides a solution to mistaken location calculations based on multipath effects. The present invention determines a real-time location of an object in a facility using a combination of location algorithms, with a signal characteristic for a wireless signal from a communication device attached to the object received at a sensor of a mesh network. The location algorithms preferably include at least two of a proximity algorithm, a radial basis function algorithm, a maximum likelihood algorithm, a genetic algorithm, a minimum mean squared error algorithm, a radiofrequency fingerprinting algorithm, a multilateration algorithm, a time difference of arrival algorithm, a signal strength algorithm, a time of arrival algorithm, an angle of arrival algorithm, a spatial diversity algorithm, and a nearest neighbor algorithm.

Claims

1. A method for determining a real-time location of an object within a facility, the method comprising:

transmitting a wireless signal from a communication device associated with an object;

receiving the wireless signal at least one of a plurality of sensors positioned within a facility, the plurality of sensors forming a mesh network;

forwarding the wireless signal from the mesh network to each of the plurality of location engines; and

determining a real-time location of the object in the facility at each of the plurality of location engines, each of the plurality of location engines using an algorithm comprising a plurality of location sub-algorithms with a signal characteristic for the wireless signal received at the at least one of a plurality of sensors, wherein the signal characteristic is a power value, an angle, or an ultrasound phase,

wherein the plurality of location sub-algorithms comprise at least one of a voting algorithm, an averaging algorithm and a confidence algorithm.

2. The method according to claim 1 wherein the plurality of location sub-algorithms includes at least two of a proximity algorithm, a radial basis function algorithm, a maximum likelihood algorithm, a genetic algorithm, a minimum mean squared error algorithm, a radiofrequency fingerprinting algorithm, a multilateration algorithm, an angle of arrival algorithm, a spatial diversity algorithm, and a nearest neighbor algorithm.

3. The method according to claim 1 wherein determining a real-time location of the object in the facility at each of the plurality of location engines comprises using a first algorithm if the object is detected in an in-room area and has a threshold RSSI, and using a second algorithm if the object is not in an in-room area or a threshold RSSI is not detected.

4. The method according to claim 1 wherein each of the plurality of location engines is located at a single server.

5. The method according to claim 1 further comprising associating the transmitting object with a second object.

6. The method according to claim 1 further comprising triggering an event.

7. The method according to claim 6 wherein the event is at least one of commencing a workflow event, changing the status of a workflow process, transmitting an alert, transmitting a report, changing the status of a computer, activating a camera, and changing the state of light.

8. A system for determining a real-time location of an object within a facility, the system comprising:

a plurality of objects, each of the plurality of objects comprising a communication device which transmits a wireless signal;

a plurality of sensors positioned within the facility, at least one of the plurality of sensors receiving the wireless signal, the plurality of sensors forming a mesh network;

a plurality of location engines, each of the plurality of location engines in communication with the mesh network, each of the plurality of location engines configured to determine a real-time location of the object from the wireless signal utilizing a location algorithm, wherein the location algorithm for each of the plurality of location engines includes at least two of a proximity algorithm, a radial basis function algorithm, a maximum likelihood algorithm, a genetic algorithm, a minimum mean squared error algorithm, a radiofrequency fingerprinting algorithm, a multilateration algorithm, an angle of arrival algorithm, a spatial diversity algorithm, and a nearest neighbor algorithm,

wherein the plurality of location sub-algorithms comprise at least one of a voting algorithm, an averaging algorithm and a confidence algorithm.

9. The system according to claim 8 wherein at least one of the plurality of objects is a medical device or a person.

10. A method for determining a real-time location of an object within a facility, the method comprising:

receiving a wireless signal from a communication device of an object at least one of a plurality of sensors positioned within a facility, wherein the wireless signal is one of light, sound and magnetic energy;

forwarding the wireless signal from the at least one of a plurality of sensors to a first location engine;

forwarding the wireless signal from the at least one of a plurality of sensors to a second location engine;

calculating a real-time location of the object from the wireless signal utilizing a first location algorithm at the first location engine;

calculating a real-time location of the object from the wireless signal utilizing a second location algorithm at the second location engine; and

determining a real-time location of the object using the calculation from the first location engine and the calculation from the second location engine,

wherein the first location algorithm or the second location algorithm is at least one of a voting algorithm, an averaging algorithm and a confidence algorithm.

11. The method according to claim 10 wherein first location algorithm is one of a proximity algorithm, a radial basis function algorithm, a maximum likelihood algorithm, a genetic algorithm, a minimum mean squared error algorithm, a multilateration algorithm, a time difference of arrival algorithm, a signal strength algorithm, a time of arrival algorithm, an angle of arrival algorithm, a spatial diversity algorithm, and a nearest neighbor algorithm.

12. The method according to claim 10 wherein second location algorithm is one of a proximity algorithm, a radial basis function algorithm, a maximum likelihood algorithm, a genetic algorithm, a minimum mean squared error algorithm, a multilateration algorithm, a time difference of arrival algorithm, a signal strength algorithm, a time of arrival algorithm, an angle of arrival algorithm, a spatial diversity algorithm, and a nearest neighbor algorithm.