Asset and personnel tagging system utilizing GPS

• US 6,700,533 B1
• Filed: 05/04/2000
• Issued: 03/02/2004
• Est. Priority Date: 05/06/1999
• Status: Expired due to Term

• Current Assignee: RF Technologies, Inc. (Microwave Techniques LLC)
• Original Assignee: RF Technologies, Inc. (Microwave Techniques LLC)
• Inventors: Long, Martin, Underriner, Kevin, Werb, Jay
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US09/564,931
• Time in Patent Office: 1,398 Days
• Field of Search: 342/357.07, 342/357.09, 342/357.1, 342/357.03, 342/357.14, 701/215, 701/220
• US Class Current: 342/357.48
• CPC Class Codes: G01S 2205/002 for traffic control, mobile tracking, guidance, surveillance or anti-collision
• CPC Class Codes: G01S 5/0018 Transmission from mobile station to base station

Abstract

A system for tracking objects outdoors. Tags attached to objects such as trailers include GPS receivers. Tags transmit uncorrected position and satellite data to a base station, where differential corrections are applied, providing 2-5 meter accuracy of the position of the tag and object. Tags are on a low duty cycle. When a tag powers on, it receives accurate time and current satellite data from the base station, enabling the tags to acquire the satellite signal quickly and with minimum power consumption. When a tag is out of base station range, the tag periodically calculates and archives its position. The tag may also include Real Time Locating Systems technology, to enable tracking to continue when the tag moves indoors and becomes inaccessible to GPS satellite signals.

Claims

1. An object locating system utilizing GPS including a tag, attached to the object, comprising:

a base station including a receiver for receiving a tag signal from the tag, and a processor; and

the tag comprising;

GPS circuitry including a GPS receiver for receiving a GPS signal; and

communication circuitry enabling wireless communication between the base station and the tag, the communication circuitry including a transmitter for transmitting the tag signal to the base station;

wherein the tag signal transmitted to the base station receiver includes GPS-based position information derived from the GPS signal and tag information; and

wherein the processor at the base station is adapted to determine a position of the tag using any one of and both of the tag signal and the GPS-based position information received from the tag signal.

2. The system as claimed in claim 1, wherein the base station further comprises a transmitter for transmitting an information signal to the tag, wherein the tag includes a power-saving device by which the tag sleeps periodically, and wherein the communication circuitry further includes a receiver for receiving, when the tag awakes from sleeping, the information signal from the base station.

3. The system as claimed in claim 2, wherein the information signal includes at least one of a position of the base station, a time, altitude and GPS satellite information.

4. The system as claimed in claim 1, wherein the tag has a motion detector adapted to awaken the tag when the motion detector detects motion of the tag.

5. The system as claimed in claim 4, wherein the tag is configured such that a position of the tag is determined more frequently when the tag is in range of the base station and the motion detector determines that the tag is in motion, than when the motion detector determines that the tag is not in motion.

6. The system as claimed in claim 4, wherein the tag is configured to archive the position of the tag periodically when the tag is out of range of the base station and the motion detector determines that the tag is in motion.

7. The system as claimed in claim 6, wherein the base station is configured to, when the tag is back in range of the base station, download a time-stamped archive from the tag.

8. The system as claimed in claim 1, wherein one of the tag and base station are configured to apply differential corrections to a position of the tag based on the GPS-based position information.

9. The system as claimed in claim 1, wherein the base station further includes a transmitter for transmitting an information signal, including commands, to the tag, wherein the tag includes a receiver for receiving the information signal from the base station and a power savings device;

and wherein the power savings device controls how frequently the tag determines its position based on the commands received from the base station.

10. The system as claimed in claim 1, wherein the base station includes a wireless LAN that is used for communication of the tag signal between the tag and the base station.

11. The system as claimed in claim 1, wherein the tag further comprises a receiver for receiving information from the object relating to operating characteristics of the object, and the transmitter is configured to also transmit the information to the base station.

12. The system as claimed in claim 10, wherein the base station is configured such that when the tag does not receive adequate GPS signals to determine the position of the tag, the wireless LAN is configured to estimate a position of the tag based on the tag'"'"'s proximity to a wireless LAN access point coupled to the base station.

13. The system as claimed in claim 1, the tag further including RFID electronics.

14. The system as claimed in claim 1, the tag further including LPS electronics.

15. The system as claimed in claim 1, wherein the base station includes a GPS receiver that receives GPS position signals, wherein the tag further includes a receiver for receiving a signal from the base station, and wherein the base station is adapted to send satellite information to the tag to assist the GPS circuitry in the tag in receiving the GPS signal.

16. The object locating system as claimed in claim 1, wherein the processor at the base station is adapted to use the tag signal to determine that the tag is within range of the base station.

17. The object locating system as claimed in claim 1, wherein the base station comprises a plurality of antennas and a real-time location device, and wherein the base station is adapted to determine the non-GPS based position information of the tag based on the tag signal transmitted from the tag to at least some of the plurality of antennas with the real-time location device.

18. The object locating system as claimed in claim 1, wherein the tag further comprises inertial tracking circuitry including a motion detector that generates a motion signal in response to movement of the tag, and a processor that calculates cumulative inertial motion of the tag based on the motion signal received from the motion detector.

19. The object locating system as claimed in claim 18, wherein the tag is configured to transmit the tag signal including the cumulative inertial motion of the tag to the base station using the transmitter.

20. An object locating system utilizing GPS including a tag, attached to the object, comprising:

a base station including a receiver for receiving a tag signal from the tag, and a processor; and

the tag comprising;

GPS circuitry including a GPS receiver for receiving a GPS signal; and

wireless LAN circuitry enabling communication between the base station and the tag;

wherein the tag is configured such that the GPS circuitry in the tag operates more frequently to receive the GPS signal and to determine a position of the tag when the tag is able to communicate by the wireless LAN circuitry with the base station than when the tag is unable to communicate by the wireless LAN circuitry with the base station.

21. The system of claim 20, wherein the GPS circuitry in the tag is configured to operate only when the tag is able to communicate by the wireless LAN circuitry with the base station.

22. The system as claimed in claim 20, wherein the tag has a power-saving device that includes a motion detector within the tag.

23. The system as claimed in claim 22, wherein the system is configured such that a position of the tag is determined more frequently when the tag is in range of the base station such that the tag can communicate by the wireless LAN circuitry with the base station, and the motion detector determines that the tag is in motion, than when the motion detector determines that the tag is not in motion.

24. The system as claimed in claim 23, wherein the tag is configured to time stamp and archive the position of the tag periodically when the tag is out of range of the base station such that the tag can not communicate by the wireless LAN circuitry with the base station, and the motion detector determines that the tag is in motion.

25. The system as claimed in claim 24, wherein the system is configured such that when the tag is in range of the base station, the time-stamped archive is downloaded from the tag by the base station.

26. The system as claimed in claim 20, wherein the system is configured such that differential corrections to a position of the tag based on the GPS signal are applied one of at the tag and at the base station.

27. The system as claimed in claim 20, wherein the base station further includes a transmitter for transmitting an information signal, including commands, to the tag, wherein the tag includes a receiver for receiving the information signal from the base station and a power savings device;

and wherein the power savings device controls how frequently the tag determines its position based on the commands received from the base station.

28. The system as claimed in claim 20, wherein the base station further comprises wireless LAN circuitry and wherein the base station is configured such that when the tag does not receive adequate GPS signals to determine the position of the tag, the base station wireless LAN circuitry is used to estimate a position of the tag based on the tag'"'"'s proximity to a wireless LAN access point coupled to the base station.

29. The system as claimed in claim 20, the tag further including one of RFID and LPS electronics.

30. An object locating system utilizing GPS including a tag, attached to the object, comprising:

a base station comprising a processor and a receiver, coupled to the processor, for receiving a tag signal from the tag; and

the tag comprising;

GPS circuitry including a GPS receiver for receiving GPS signals and

communication circuitry enabling wireless communication between the base station and the tag;

wherein the processor at the base station is adapted to determine a position of the tag based on GPS-based position information received from the tag in the tag signal; and

wherein the communication circuitry comprises a transmitter that transmits the tag signal to the base station, and wherein the processor at the base station is further adapted to determine the position of the tag based on reception of the tag signal.

31. The system of claim 30, the tag further comprising:

a processor for determining GPS-based position information based on the GPS signals; and

a power-saving device that enables the tag to switch between a sleeping state and an awake state.

32. The system as claimed in claim 31, wherein the power saving device further comprises a motion detector, coupled to the processor, and wherein the processor in the tag is adapted to calculate cumulative inertial motion of the tag based on a motion signal received from the motion detector.

33. The system as claimed in claim 31, wherein a control signal transmitted from the base station includes instructions that control a frequency at which the power-saving device switches the tag between the sleeping state and the awake state.

34. The system as claimed in claim 33, wherein the control signal further includes information about a location of a GPS satellite.