Using a mesh of radio frequency identification tags for tracking entities at a site
First Claim
1. A method for tracking entities, to determine at least a relative location of the entities at a site, comprising the steps of:
- (a) creating a mesh network at the site that is formed of a plurality of portable radio frequency identification (RFID) tags, and a plurality of fixed RFID tags, all of which transmit and receive radio signals, the portable RFID tags each being associated with a different entity from a plurality of different types of entities that can move around at the site, each portable RFID tag being physically coupled or attached to the entity with which it is associated, at least some of the portable and static RFID tags that are associated with the entities including a sensor for detecting when the RFID tags are in motion, wherein a portable RFID tag that has not moved from a previous known location comprises a static RFID tag, and wherein the plurality of fixed RFID tags remain in at known locations;
(b) repetitively causing each RFID tag to transmit a signal that conveys an identification of the RFID tag that is transmitting the signal, the signal that is transmitted being received by any other RFID tag disposed within a receiving range of the signal that was transmitted, wherein the RFID tags that are receiving the signal include one or more of the fixed RFID tags or static RFID tags, each fixed or static RFID tag having a known position on the site, and wherein the step of repetitively causing each RFID tag that is associated with one of the entities to transmit a signal includes the step of causing each RFID tag having a sensor that is detecting movement of the RFID tag, to continuously or at least more frequently transmit a signal identifying a portable RFID tag that is in motion, so that the portable RFID tag that is in motion can be at least tracked in a coarse tracking mode as the portable RFID tag is moved about at the site;
(c) each RFID tag that receives the signal being transmitted determining a location indicative parameter and saving the location indicative parameter in connection with the identification of the RFID tag that transmitted the signal;
(d) forwarding data comprising the location indicative parameter and identification of each portable RFID tag that is moving, for each of the signals that was received by an RFID tag, to a processor, along with an identification of the RFID tag that is forwarding the data; and
(e) using collaborative multi-lateration for processing location indicative parameters in relation to the known positions of the fixed or static RFID tags and the identification of the RFID tags forwarding the data, as well as the identification of the portable and fixed or static RFID tags originally transmitting signals, for determining at least relative positions of the entities at the site.
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Accused Products
Abstract
A system for tracking entities at a site comprises a mesh of radio frequency identification (RFID) tags. Each of the tracked entities, which may move about the site, is associated with and attached to a portable RFID tag. Each RFID tag is at least periodically caused to transmit a signal that includes an identification of the RFID tag. The signal is received by other RFID tags that are within range, which determine a location indicative parameter. Some of the RFID tags receiving the signal are fixed at predefined locations. Specific fixed RFID tags are designated as controller nodes. Data comprising an identification of the RFID tag receiving a signal, the location indicative parameter, and the identification of the portable RFID tag transmitting the signal are communicated to a location engine server, which processes the data to determine at least a relative position of the portable RFID tags on the site.
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Citations
34 Claims
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1. A method for tracking entities, to determine at least a relative location of the entities at a site, comprising the steps of:
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(a) creating a mesh network at the site that is formed of a plurality of portable radio frequency identification (RFID) tags, and a plurality of fixed RFID tags, all of which transmit and receive radio signals, the portable RFID tags each being associated with a different entity from a plurality of different types of entities that can move around at the site, each portable RFID tag being physically coupled or attached to the entity with which it is associated, at least some of the portable and static RFID tags that are associated with the entities including a sensor for detecting when the RFID tags are in motion, wherein a portable RFID tag that has not moved from a previous known location comprises a static RFID tag, and wherein the plurality of fixed RFID tags remain in at known locations; (b) repetitively causing each RFID tag to transmit a signal that conveys an identification of the RFID tag that is transmitting the signal, the signal that is transmitted being received by any other RFID tag disposed within a receiving range of the signal that was transmitted, wherein the RFID tags that are receiving the signal include one or more of the fixed RFID tags or static RFID tags, each fixed or static RFID tag having a known position on the site, and wherein the step of repetitively causing each RFID tag that is associated with one of the entities to transmit a signal includes the step of causing each RFID tag having a sensor that is detecting movement of the RFID tag, to continuously or at least more frequently transmit a signal identifying a portable RFID tag that is in motion, so that the portable RFID tag that is in motion can be at least tracked in a coarse tracking mode as the portable RFID tag is moved about at the site; (c) each RFID tag that receives the signal being transmitted determining a location indicative parameter and saving the location indicative parameter in connection with the identification of the RFID tag that transmitted the signal; (d) forwarding data comprising the location indicative parameter and identification of each portable RFID tag that is moving, for each of the signals that was received by an RFID tag, to a processor, along with an identification of the RFID tag that is forwarding the data; and (e) using collaborative multi-lateration for processing location indicative parameters in relation to the known positions of the fixed or static RFID tags and the identification of the RFID tags forwarding the data, as well as the identification of the portable and fixed or static RFID tags originally transmitting signals, for determining at least relative positions of the entities at the site. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 32, 33)
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2. A system for tracking entities, to determine at least a relative location of the entities at a site, comprising:
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(a) a mesh network comprising a plurality of radio frequency identification (RFID) tags, including at least one fixed RFID tag, which is not moved from a known location, or at least one static RFID tag currently disposed at a known location at the site, and a plurality of portable RFID tags, each portable RFID tag being associated with a different one of the entities that can move about at the site and physically coupled or attached to the entity with which it is associated, the static RFID tag comprising a portable RFID tag that has not moved from its last known location, each of the RFID tags being controlled so as to transmit a signal that includes an identification of the RFID tag transmitting the signal, the signal being received by any other of the plurality of RFID tags that is in range, each RFID tag that receives the signal determining a location indicative parameter for the signal and storing the location indicative parameter in connection with the identification of the RFID tag transmitting the signal, at least some of the plurality of portable RFID tags including a sensor that detects when the portable RFID tag and the object to which it is attached or coupled is in motion, the portable RFID tag that is in motion responding to the sensor detecting the motion of the portable RFID tag by continuously or at least more frequently transmitting the signal identifying the portable RFID tag that is in motion, so that the portable RFID tag can at least be tracked in a coarse tracking mode by the system as the portable RFID tag is moved about at the site; and (b) a processor that is configured to carry out a plurality of functions, including; (i) repetitively causing each RFID tag that is associated with one of the entities to transmit the signal; (ii) receiving data comprising the location indicative parameter and identification of the RFID tag for each of the signals that was received by an RFID tag, when forwarded from the plurality of RFID tags; and (iii) using collaborative multi-lateration for processing location indicative parameters in relation to the known positions of the fixed or static RFID tags and the identification of the RFID tags forwarding the data, as well as the identification of the portable and fixed or static RFID tags originally transmitting signals, for determining at least relative positions of the entities at the site.
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19. A system for tracking entities, to determine at least a relative location of the entities at a site, comprising:
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(a) a mesh network comprising a plurality of radio frequency identification (RFID) tags, including at least one fixed RFID tag or at least one static RFID tag disposed at a predefined location at the site, and a plurality of portable RFID tags, each portable RFID tag being associated with a different one of the entities that can move about at the site and physically coupled or attached to the entity with which it is associated, the static RFID tag comprising a portable RFID tag that has not moved from a known location, each of the RFID tags being controlled so as to transmit a signal that includes an identification of the RFID tag transmitting the signal, the signal being received by any other of the plurality of RFID tags that is in range, each RFID tag that receives the signal determining a location indicative parameter for the signal and storing the location indicative parameter in connection with the identification of the RFID tag transmitting the signal; and (b) a processor that is configured to carry out a plurality of functions, including; (i) repetitively causing each RFID tag that is associated with one of the entities to transmit the signal; (ii) receiving data comprising the location indicative parameter and identification of the RFID tag for each of the signals that was received by an RFID tag, when forwarded from the plurality of RFID tags; and (iii) using collaborative multi-lateration for processing location indicative parameters in relation to the known positions of the fixed or static RFID tags and the identification of the RFID tags forwarding the data, as well as the identification of the portable and fixed or static RFID tags originally transmitting signals, for determining at least relative positions of the entities at the site. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 34)
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Specification