Wireless Tracking System And Method With Optical tag Removal Detection

• US 20090102665A1
• Filed: 02/24/2008
• Published: 04/23/2009
• Est. Priority Date: 10/19/2007
• Status: Active Grant

• Current Assignee: Centrak Incorporated (Halma PLC)
• Original Assignee: Awarepoint Corporation
• Inventors: Caliri, Dyami, Smith, Derek, Baranowski, Robert
• Granted Patent: US 7,564,357 B2
• Time in Patent Office: Days
• US Class Current: 340/572.800
• CPC Class Codes: G08B 13/1436 with motion detection
• CPC Class Codes: G08B 13/1481 with optical detection
• CPC Class Codes: G08B 13/2448 Tag with at least dual detection means, e.g. combined inductive and ferromagnetic tags, dual frequencies within a single technology, tampering detection or signalling means on the tag

Abstract

A wireless tracking system and method with a tag removal detection feature is disclosed herein. The system and method utilize a tag attached to an asset which includes a processor, a motion sensor (such as an accelerometer), a transceiver, a tag removal sensor and a power source having a limited supply of power. The tag removal sensor is an optical sensor which is activated only when the motion sensor detects motion. In this manner, the tag conserves power since the tag is typically only in motion ten percent of the day. If the tag is removed from the asset, the optical sensor confirms the removal and an alert is activated by the system.

Claims

1. A system for determining if a tag has been removed from an asset within an indoor facility, the system comprising:

a plurality of network sensors, each of the plurality of network sensors positioned within an indoor facility;

a tracking tag attached to an asset, the tracking tag comprising

a housing having a window,

a microcontroller positioned within the housing, the microcontroller capable of generating a location signal at a motion rate and at a stationary rate,

a wireless network interface positioned within the housing and connected to the microcontroller, the wireless network interface transmitting the location signal from the tracking tag to at least one of the plurality of network sensors using a wireless communication format,

a power supply positioned within the housing and connected to the microcontroller,

a motion sensor positioned within the housing and connected to the microcontroller, the motion sensor transmitting a signal to the microcontroller when the device is in motion, and

an optical sensor positioned within the housing, the optical sensor comprising an emitter for emitting a light beam through the window of the housing of the device, a photodiode for receiving a reflected light beam generated by the emitter, the optical sensor having a resting mode to conserve power consumption and an activation mode to determine if the device is attached to an asset, wherein during the activation mode the emitter generates the light beam which is reflected off the asset and received by the photodiode if the tag is attached to the object; and

a positioning engine in communication with each of the plurality of network sensors.