Active badge localization using passive sensors

• US 8,284,026 B2
• Filed: 01/29/2010
• Issued: 10/09/2012
• Est. Priority Date: 01/29/2010
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Ivanov, Yuri, Goldsmith, Abraham, Thornton, Jay
• Primary Examiner(s): Wu, Daniel
• Assistant Examiner(s): Terrell, Emily C
• Application Number:
  US12/696,254
• Publication Number:
  US 20110187502A1
• Time in Patent Office: 984 Days
• Field of Search: 340/6.1, 340/3.7, 340/5.3, 340/500
• US Class Current: 340/6.1
• CPC Class Codes: G07C 9/28 the pass enabling tracking or indicating presence
• CPC Class Codes: G08B 5/22 using electric transmission; using electromagnetic transmission

Abstract

A network in an environment includes passive sensors with associated sensor identification numbers. A set of active badges with associated badge identification numbers, wherein each badge is associated with an object, and wherein a particular sensor broadcasts a packet in response to detecting a particular object, wherein the packet includes the sensor identification number and a time, and only if the particular object is associated with a particular badge then the badge appends the badge identification number to the packet and broadcasts the appended packet, and the particular sensor receives and rebroadcasts the appended packet for further processing to passively and actively monitor the environment.

Claims

1. A system, wherein the system is configured to monitor an environment, comprising:

a network of sensors, wherein each sensor is passive and has an associated sensor identification number, and wherein the sensors are distributed in the environment; and

a set of badges, wherein each badge is active and has an associated badge identification number, wherein each badge is associated with an object, and wherein a particular sensor broadcasts a packet in response to detecting a particular object, wherein the packet includes the sensor identification number and a time, and only if the particular object is associated with a particular badge then the badge appends the badge identification number to the packet and broadcasts the appended packet, and the particular sensor receives and rebroadcasts the appended packet for further processing to passively and actively monitor the environment.

2. The system of claim 1, wherein each sensor further comprises:

a motion sensor; and

a wireless transceiver.

3. The system of claim 2, wherein the wireless transceiver operates according to the IEEE 802.15.4 standard.

4. The system of claim 2, further comprising:

relay nodes configured to interconnect all of the sensor nodes.

5. The system of claim 2, wherein the motion sensor further comprises:

an infrared detector.

6. The system of claim 1, further comprising:

a means for tracking the object over time using the packet broadcast by the sensor.

7. The system of claim 1, wherein the location of each sensor is known.

8. The system of claim 1, wherein the processing is centralized.

9. The system of claim 1, wherein the processing is distributed.

10. The system of claim 1, wherein the badge further comprises:

a radio-frequency identification (RFID) tag.

11. The system of claim 1, wherein the packet includes a radio signal strength indicator.

12. The system of claim 11, wherein the RSSI is used to determine a nearest sensor to the particular badge.

13. The system of claim 1, wherein the further processing generates an appropriate alarm signal.

14. The system of claim 1, wherein the sensors are distributed in health care, educational, hospitality, military, law enforcement, home, industrial, or entertainment environments.

15. The system of claim 1, further comprising:

a means for tracking the object over time using the packet rebroadcast by the sensor.

16. A method for monitoring an environment, comprising the steps of:

detecting an object in the environment by a sensor, wherein the sensor is passive and has an associated sensor identification number;

broadcasting initially a packet in response to detecting the object, wherein the packet includes a sensor identification number and a time;

receiving the packet by a badge associated with the object, wherein the badge is active and has an associated badge identification number;

broadcasting the packet by the badge after appending the badge identification number;

receiving and rebroadcasting the appended packet by the sensor for further processing to passively and actively monitor the environment.