Asset tracking system

• US 8,373,562 B1
• Filed: 07/23/2008
• Issued: 02/12/2013
• Est. Priority Date: 07/25/2007
• Status: Active Grant

• Current Assignee: RF Technologies, Inc. (Microwave Techniques LLC)
• Original Assignee: Pinpoint Technologies, Inc. (Asahi Kasei Corporation)
• Inventors: Heinze, Eric T., Haensgen, Gregg J., Eckelman, Brian, Gary, Wyndham F. Jr.
• Primary Examiner(s): Zimmerman, Brian
• Assistant Examiner(s): Alizada, Omeed
• Application Number:
  US12/178,480
• Time in Patent Office: 1,665 Days
• Field of Search: None
• US Class Current: 340/572.1
• CPC Class Codes: G06Q 10/06 Resources, workflows, human or project management; Enterprise or organisation planning; Enterprise or organisation modelling
• CPC Class Codes: G08B 13/1427 with transmitter-receiver for distance detection
• CPC Class Codes: G08B 21/0227 System arrangements with a plurality of child units
• CPC Class Codes: G08B 21/0258 System arrangements wherein both parent and child units can emit and receive
• CPC Class Codes: G08B 21/0277 Communication between units on a local network, e.g. Bluetooth, piconet, zigbee, Wireless Personal Area Networks [WPAN]
• CPC Class Codes: G08B 21/028 Communication between parent and child units via remote transmission means, e.g. satellite network
• CPC Class Codes: G08B 21/0286 Tampering or removal detection of the child unit from child or article

Abstract

An asset tracking system includes a station, transmitting points, and tag units. The tag units can be used for communicating with the transmitting points. The station receives data associated with signal strengths between wireless access points and tag units. The station analyzes the data associated with a number of the transmitting points and determines the location of the tag units.

Claims

1. An asset tracking system, comprising:

a plurality of transmitting points, the transmitting points each having a MAC address header, the MAC address header including an organizational unique identifier indicating status as a transmitting point as opposed to an access point, the transmitting points operating in a frequency range associated with an 802.11 standard and not being an 802.11 access point; and

a tag unit configured to communicate with the plurality of transmitting points and a plurality of access points and configured to distinguish between the access points and the transmitting points using the organizational unique identifier, the tag unit configured to receive RF signals from the transmitting points and the access points, wherein a positioning station is configured to receive data associated with signal strengths of the RF signals, wherein the data is analyzed to determine a location of the tag unit, wherein position is determined by comparing the data to stored signal strengths associated with particular locations, wherein the tag unit is configured to provide the data to the positioning station via an access point of the access points associated with the strongest signal strength in the data, wherein the tag unit includes a motion detector, wherein the tag unit is powered down when stationary.

2. The system of claim 1, further comprising at least one wireless access point.

3. The system of claim 1, wherein positioning station uses a location algorithm, the location algorithm using AP map matrixing, centering, averaging, or vectoring.

4. The system of claim 3, wherein the positioning station tracks a time for the tag unit being at the location.

5. The system of claim 3, wherein the positioning station displays an indication of the location on a map.

6. The system of claim 5, wherein the location of the tag unit is analyzed with respect to a location type or a room type to monitor workflow.

7. The system of claim 5, wherein the positioning station provides the map to a mobile device, including a handheld computer or a laptop.

8. The system of claim 1, wherein the tag unit operates in a power saving mode.

9. The system of claim 1, wherein positioning station determines the location using calibration data collected during installation, historical movements, and statistical analysis.

10. An asset tracking system, comprising:

a positioning input point configured to transmit a second probe signal in response to a probe request, wherein the positioning input point is not an access point for a network and provides a MAC address having an organizational unique identifier;

a tag unit configured to communicate with a plurality of access points and the position input point and distinguish between the access points and the position input point using the organizational unique identifier, the tag unit configured to receive the second probe signal from the position input point and first probe signals from the access points, wherein the tag unit includes a motion detector, wherein the tag unit is powered down when stationary, the first probe signals and the second probe signals being RF signals; and

a positioning station configured to receive data associated with signal strengths of the RF signals between the positioning input point and the tag unit and the access points and the tag unit and to determine a location of the tag unit by comparing the data to stored signal strengths associated with particular locations, wherein the tag unit is configured to provide the data to the positioning station via an access point of the access points associated with the strongest signal strength in the data.

11. The system of claim 10, wherein a routing list is generated using the locations for preventative maintenance.

12. The system of claim 10, wherein the positioning station includes resource profiles assigned during initial set-up.

13. The system of claim 10, wherein the tag unit sends an alert signal to a known SSID and IP address when a tamper circuit is activated.

14. The system of claim 10, wherein the positioning station provides a notification when the tag unit is removed from an assigned area.

15. The system of claim 10, wherein the positioning station sets a motion flag for the tag unit when the tag unit is moved, wherein the station monitors the locations of the tag unit to determine if the tag unit is moved without the motion flag being set.

16. The system of claim 10, wherein the plurality of access points operate in a continuous receive mode and does not restrict packets into classes.

17. The system of claim 16, wherein the plurality of access points can monitor packets from WiFi devices and assist asset tracking without loading asset tracking client software onto the devices.

18. A method of locating an asset tag, comprising:

receiving a plurality of probe signals from a plurality of transmitting points and access points, the transmitting points being incapable of providing network access;

storing data associated with the signal strength of the plurality of probe signals, wherein the data includes an identifier of a respective transmitting point of the plurality of transmitting points in the asset tag, wherein the asset tag distinguishes between an 802.11 access point and the respective transmitting point using an organizational unique identifier, the respective transmitting points transmitting in an 802.11 format, wherein the organizational unique identifier is at a header of a MAC address and indicates that the respective transmitting point is not an access point, wherein the asset tag includes a motion detector, wherein the asset tag is powered down when stationary; and

transmitting the stored data to a positioning station from the asset tag, wherein the positioning station analyzes the data and determines a location of the asset tag, wherein the asset tag is configured to provide the data to the positioning station via an access point of the access points associated with the strongest signal strength in the stored data.

19. The method of claim 18, wherein the positioning station displays an indication of the location on a map.

20. The method of claim 18, wherein the positioning station tracks a time for the tag unit being at the location.