Personnel and asset tracking method and apparatus

• US 6,344,794 B1
• Filed: 01/07/2000
• Issued: 02/05/2002
• Est. Priority Date: 11/03/1997
• Status: Expired due to Term

• Current Assignee: Hill-Rom Services Incorporated (Baxter International Inc.)
• Original Assignee: Arial Systems Corporation, Hill-Rom Incorporated (Baxter International Inc.)
• Inventors: Schmid, Joseph J., Patel, Sanjeev, Ulrich, Daniel J., Jennings, Robert J., Wagener, Michael Edward
• Primary Examiner(s): POPE, DARYL C
• Application Number:
  US09/479,359
• Time in Patent Office: 760 Days
• Field of Search: 340/539, 340/573.1, 340/825.36, 340/825.49, 340/573.4
• US Class Current: 340/539.16
• CPC Class Codes: G06K 17/0022 arrangements or provisious for transferring data to distant stations, e.g. from a sensing device "transfer between computer elements G06F13/00 "; data-transmission H04L

Abstract

A personnel and asset tracking system for locating and tracking objects throughout an awareness area comprises a communication network, a central server connected to said communication network maintaining an awareness area database, a plurality of receiver nodes, and a plurality of tags. Each tag is associated with an object to be tracked and has a transmitter which periodically transmits a tag transmission including a unique object identifier.

Claims

1. A personnel and asset tracking system for locating and tracking objects throughout an awareness area, said personnel and asset tracking system comprising:

a communication network;

a central server connected to said communication network maintaining an awareness area database;

a plurality of tags, each tag being associated with an object to be tracked and having a transmitter which periodically transmits a tag transmission, said tag transmission including a unique object identifier;

an independent monitoring system monitoring a first sub-awareness area covering a portion of said awareness area, an assigned subset of said tags being assigned to said independent monitoring system, said independent monitoring system comprising;

a master station connected to said communication network, said master station maintaining a sub-awareness area database containing a location for each of said assigned subset of said tags,

an intermediate location processor connected to said master station,

a plurality of independent receiver nodes connected to said intermediate location processor and configured to receive tag transmissions from a portion of said first sub-awareness area;

wherein receiver location messages are generated by said plurality of independent receiver nodes in response to a received tag transmission from a proximate one of said plurality of tags and are transmitted to said intermediate location processor, said intermediate location processor processes said receiver location messages and transmits intermediate location messages to said master station, said master station processes said intermediate location messages and transmits master location messages to said central server over said communication network, processing by said master station including updating said sub-awareness area database with the location of said proximate one of said plurality of tags;

a second monitoring system monitoring a second sub-awareness area covering a portion of said awareness area, said second monitoring system generating downstream location messages in response to tag transmissions received in said second sub-awareness area and transmitting said downstream location messages to said central server over said communication network;

said central server updating said awareness area database with said master and downstream location messages received, responding to queries by said master station, and determining whether said downstream location message is for one of said assigned subset of said plurality of tags and, if so, generating a network location message identifying said one of said assigned subset of said plurality of tags and its location and transmitting said network location message to said independent monitoring over said communication network for updating said sub-awareness area database.

2. The personnel and asset tracking system of claim 1, wherein processing of said intermediate location message by said master station includes determining whether said proximate one of said plurality of tags is in said assigned subset of said plurality of tags or is currently being tracked by said independent monitoring system and, if not, sending an identification request to said central server to identify said proximate one of said plurality of tags, and

wherein said central server, upon receipt of said identification request, determines the identity of said proximate one of said plurality of tags using said awareness area database, and sends said identity to said master station, and said master station updates said sub-awareness area database with the identity of said proximate one of said plurality of tags for tracking by said independent monitoring system while said proximate one of said plurality of tags is in said sub-awareness area.

3. The personnel and asset tracking system of claim 1, wherein each of said plurality of receivers includes a receiver clock, a receiver cache containing tag records;

each of said tag records including a tag identifier identifying one of said plurality of tags, a time stamp indicating the time when a tag transmission was received from said one of said plurality of tags and an exit timer indicating the time since the most recent tag transmission was received from said one of said plurality of tags,

wherein, when a current receiver of said plurality of receivers receives a tag transmission from a current tag which is one of said plurality of tags, said current receiver determines whether one of said tag records is for said current tag, when one of said tag records is for said current tag, said current receiver resets the exit timer in said one of said tag records for said current tag and does not generate said receiver location message, otherwise, said current receiver adds a tag record for said current tag to said receiver cache, generates said receiver location message and sends said receiver location message to said intermediate location processor;

said receiver location message including a current tag identifier for said current tag and a current time stamp indicating when said current receiver received said tag transmission from said current receiver,

wherein, when an exit timer expires in an expired tag record of a receiver cache of one of said plurality of receivers, said one of said plurality of receivers removes said expired tag record from said receiver cache, and sends an exit location message to said intermediate location processor, said exit location message including an expired tag identifier from said expired tag record.

4. The personnel and asset tracking system of claim 3, wherein said intermediate location processor includes an intermediate cache containing an object stack for each of said plurality of tags being tracked by any of said plurality of receivers connected to said intermediate location processor, an object stack for a tracked tag of said plurality of tags containing intermediate records which include a receiver identifier identifying a tracking receiver of said plurality of receivers which received a tag transmission from said tracked tag, and an associated time stamp indicating when a tag transmission was received from said tracked tag by said tracking receiver,

wherein, when said intermediate location processor receives said receiver location message including said current tag identifier and said current time stamp from said current receiver, said intermediate location processor determines whether there is an object stack for said current tag is in said intermediate cache, when there is not an object stack for said current tag, said intermediate location processor adds an object stack for said current tag to said intermediate cache, adds an intermediate record to said object stack for said current tag which includes an identifier for said current receiver and said current time stamp, generates and sends said intermediate location message;

when there is an object stack for said current tag but the intermediate record at the top of said object stack for said current tag is not associated with said current receiver, said intermediate location processor adds an intermediate record to the top of said object stack for said current tag which includes an identifier for said current receiver and said current time stamp, generates and sends said intermediate location message;

otherwise, said intermediate location processor does not send an intermediate location message in response to said receiver message;

wherein, when said intermediate location processor receives an exit location message from an expired receiver of said plurality of receivers, said intermediate location processor determines whether there is an object stack for an expired tag associated with said expired object identifier, when there is an object stack for a said expired tag and said expired receiver is associated with the top intermediate record in said object stack for said expired tag, said intermediate location processor removes the top intermediate record in said object stack for said expired tag, generates and sends an intermediate exit message;

said intermediate exit message including said expired tag identifier from said exit location message.

5. The personnel and asset tracking system of claim 1, wherein said central server can receive communications from a client computer connectable to said communication network, wherein the central server can receive messages from said client computer, translate said message to determine database queries and updates, process said database queries and updates, create a response message which includes the results of said database queries and updates, and transmit said response message to said client computer;

said central server maintaining an interest database containing a plurality of registered interests, each registered interest including an interest event and an interested client;

said central server monitoring updates to said awareness database to detect the occurrence of one of said plurality of interest events;

when one of said plurality of interest events occurs, said central server automatically creates and sends an interest notification message to said interested client associated the occurrence of said one of said plurality of interest events indicating the occurrence and location of the interest event.

6. The personnel and asset tracking system of claim 5 wherein each of said plurality of tags includes an action button, and said awareness database includes a user-defined system response for each of said plurality of tags that is to be taken when said action button is triggered;

such that upon triggering an action button on a particular tag, said particular tag sends an alert location message, said alert location message is given priority and transmitted to said central server, said central server queries said awareness database for a user-defined system response associated with said particular tag that originated said alert location message, said central server creates an alert notification message according to and transmits said alert notification message according to said user-defined system response.