Article locator system

• US 6,788,199 B2
• Filed: 03/12/2002
• Issued: 09/07/2004
• Est. Priority Date: 03/12/2001
• Status: Active Grant

• Current Assignee: Eureka Technology Partners LLC
• Original Assignee: Eureka Technology Partners LLC
• Inventors: Rassool, Reza P., DelMain, Gregory J., White, Peter, McArthur, Paul, Crabtree, Timothy L., Wells, Michael F.
• Primary Examiner(s): TRIEU, VAN THANH
• Application Number:
  US10/097,544
• Publication Number:
  US 20030034887A1
• Time in Patent Office: 910 Days
• Field of Search: 340/539.1, 340/539.11, 340/539.13, 340/539.14, 340/539.15, 340/539.21, 340/539.22, 340/539.32, 340/686.6, 340/686.7, 340/568.1, 340/572.1, 340/10.1, 340/10.2, 340/10.6, 340/10.42, 340/573.1, 340/573.3, 340/573.4, 342/404, 342/457, 342/126, 342/146, 342/147, 702/178
• US Class Current: 340/539.13
• CPC Class Codes: A01K 11/006 Automatic identification systems for animals, e.g. electronic devices, transponders for animals identification systems for access to feeding pens A01K1/0209; ear tags with electronic identification means A01K11/004
• CPC Class Codes: G01S 13/825 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/84 for distance determination by phase measurement
• CPC Class Codes: G01S 3/54 the apparent movement of the antenna being produced by coupling the receiver cyclically and sequentially to each of several fixed spaced antennas
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: G01S 7/4004 of parts of a radar system
• CPC Class Codes: G08B 13/1427 with transmitter-receiver for distance detection
• CPC Class Codes: G08B 21/0211 Combination with medical sensor, e.g. for measuring heart rate, temperature
• CPC Class Codes: G08B 21/0222 Message structure or message content, e.g. message protocol
• CPC Class Codes: G08B 21/0227 System arrangements with a plurality of child units
• CPC Class Codes: G08B 21/023 Power management, e.g. system sleep and wake up provisions
• CPC Class Codes: G08B 21/0247 System arrangements wherein the alarm criteria uses signal strength
• CPC Class Codes: G08B 21/0263 System arrangements wherein the object is to detect the direction in which child or item is located
• CPC Class Codes: G08B 21/028 Communication between parent and child units via remote transmission means, e.g. satellite network
• CPC Class Codes: G08B 21/0294 Display details on parent unit

Abstract

A system and method for locating objects such as people, pets, and personal articles is described. A transceiver is attached to the person, animal, or item to be tracked and a handheld locator device is employed to transmit a locator signal containing an address code to the transceiver. Upon receipt of a signal, the transceiver compares the address code contained in the locator signal with an address code stored in the transceiver. If the two codes are same, the transceiver sends a return signal back to the locator device. The locator device uses this return signal to determine the distance and/or direction of the transceiver from the user'"'"'s location. The system allows a user to select from a multiple number of items to locate and allows multiple users to search for different articles within the same general area without interference.

Claims

1. An electronic system for locating an item, comprising:

a locator module comprising;

a first memory unit operable to store one or more first address codes;

a user control operable to allow a user to select one of the stored first address codes;

a first transmitter operable to wirelessly transmit a locator signal, wherein the locator signal includes one of the selected first address codes;

a first receiver operable to receive a return signal transmitted by a transceiver module;

an antenna array operably connectable to the first transmitter and the first receiver; and

a first control unit operable to calculate a relative direction of the transceiver module from the locator module, wherein the first control unit is linked to the first memory unit, the user control, the first transmitter, and the first receiver; and

the transceiver module comprising;

a second memory unit operable to store a second address code;

a second receiver operable to receive the locator signal transmitted from the locator module;

a second transmitter operable to wirelessly transmit the return signal;

a second control unit operable to compare the selected first address code transmitted by the locator module with the second address code, and activate the second transmitter to wirelessly transmit the return signal if the two codes are the same, wherein the second control unit is linked to the second memory unit, the second receiver, and the second transmitter; and

a timer linked to the second receiver and the second control unit, the timer operable to activate the second receiver and second control unit at a specified time interval and for a specified time period.

2. The system of claim 1, wherein the locator module further comprises a second timer linked to the first control unit, the second timer operable to determine the time between when the locator signal is transmitted to when the return signal is received, and wherein the first control unit operable to calculate a distance of the transceiver module from the locator module.

3. The system of claim 1, wherein the locator unit further comprises a real-time clock.

4. The system of claim 1, wherein the locator module is configured to:

allow the user to specify a known distance from the locator module to the transceiver module;

use the known distance to determine an expected time period between when a locator signal is sent to the transceiver module to when the return signal should be received by the locator module,

measure an actual time period from when the locator signal is sent to the transceiver module to when the return signal is received by the locator module,

obtain an electronic system delay time by subtracting the actual time period from the expected time period, and

store the electronic system delay time in the first memory unit.

5. The system of claim 4, wherein the locator unit further comprises a first sensor operable to measure a first temperature, and the transceiver comprises a second sensor operable to measure a second temperature, and the first and second temperatures are used to calculate the system delay time.

6. The system of claim 1, wherein calculating the distance of the transceiver module from the locator module comprises determining a total time elapsed from when the locator signal is sent to when the return signal is received by the locator device, subtracting an electronic system propagation delay time, and dividing by two.

7. The system of claim 1, wherein the locator module determines distance to the transceiver module by switching between antennas in the antenna array according to a commutation frequency selected to minimize a tone output from said first receiver.

8. The system of claim 1, wherein the locator module determines distance to the transceiver module by switching between antennas in the antenna array according to a commutation frequency selected to minimize a tone output from said first receiver, wherein said commutation frequency is swept across a desired range of frequencies.

9. The system of claim 1, wherein the locator module is configured to measure a phase delay between a tone transmitted to the transceiver module and a tone received from the transceiver module.

10. The system of claim 1, wherein the locator module is configured to calibrate to the transceiver module, the locator module configured to:

measure a phase delay between a tone transmitted to the transceiver module and a tone received from the transceiver module when said transceiver module is relatively close to the locator module;

convert the phase delay to a time delay; and

store the system delay time.

11. The system of claim 1, wherein the first control unit is further operable to measure and store a signal processing time delay through the electronic system.

12. The system of claim 1, wherein said locator module further comprises a switch to operably connect said first receiver to said antenna array.

13. The system of claim 1, wherein said locator module further comprises a switch to operably connect said first receiver to said antenna array, and wherein said control unit controls a commutation rate of said switch.

14. The system of claim 1, wherein the timer is a real-time clock.

15. The system of claim 14, wherein the real time clock is programmable to activate the second receiver at specified times.

16. The system of claim 14, wherein the real time clock is operable to be programmed by the locator module.

17. The system of claim 1, wherein the locator module further comprises a conflict detection receiver, the conflict detection receiver linked to the first control unit and operable to detect a second locator signal transmitted from a second locator module.

18. The system of claim 17, wherein the first control unit is further operable to delay the transmission of the locator signal from the first transmitter unit when the conflict detection receiver detects the second locator signal.

19. The system of claim 17, wherein the conflict detection receiver is integral with the first receiver.

20. The system of claim 1, wherein the second memory unit is further operable to at least temporarily store a session identifier.

21. The system of claim 1, wherein the transceiver module further comprises a battery, the battery operable to power the second memory unit, the second receiver, the second transmitter, the second timer, and the second control unit.

22. The system of claim 1, wherein the transceiver module is powered by radio frequency energy.

23. The system of claim 1, wherein the transceiver module further comprises an outer housing.

24. The system of claim 23, wherein the outer housing is waterproof.

25. The system of claim 1, wherein the locator module further comprises a display screen linked to the first control unit.

26. The system of claim 1, wherein the antenna array comprises two or more antennas coupled to the locator module and arranged in a circular path.

27. The system of claim 26, wherein the two or more antennas are pivotally coupled to the locator module.

28. The system of claim 27, wherein there are three or more antennas.

29. The system of claim 26, wherein the first control unit is further operable to determine the strength of the return signal received at each of the antennas, and is operable to select the antenna receiving the strongest return signal.

30. The system of claim 1, wherein the first receiver is only active for a limited period after the locator signal is sent.

31. The system of claim 1, wherein the locator unit further comprises an internal compass unit operable to convert a relative direction of the transceiver module to a magnetic bearing.

32. The system of claim 1 further comprising a third transmitter operable to send a first signal to a second locator unit, and further comprising a third receiver operable to receive a second signal from a second locator unit.

33. The system of claim 1, further comprising one or more additional locator units, wherein the locator unit and the additional locator units are connected by a communication path.

34. The system of claim 33, wherein the communication path comprises a computer network.

35. The system of claim 1, wherein the antenna array comprises one or more monopole-type antennas.

36. The system of claim 1, wherein the antenna array comprises one or more dipole-type antennas.

37. The system of claim 1, wherein the antenna array comprises one or more patch-type antennas.

38. The system of claim 1, wherein the first transmitter transmits the first address code using frequency shift keying.

39. The system of claim 1, wherein the locator module determines bearing to the transceiver module by switching between antennas in the antenna array and using Doppler processing to determine a direction of a wireless signal received from the transceiver module.

40. The system of claim 1, wherein the locator module sends commands to said transceiver module.

41. The system of claim 1, wherein the transceiver further comprises a sensor linked to the second control unit.

42. The system of claim 41, wherein the sensor is operable to measure temperature.

43. The system of claim 1, wherein the transceiver further comprises an indicator linked to the second control unit.

44. The system of claim 1, wherein the locator signal comprises a spread spectrum signal, an ultra wide band signal, a wideband FM signal, or a CDMA signal.

45. A method for locating an object, the method comprising:

attaching a transceiver to the object, the transceiver comprising;

a first receiver operable to receive a locator signal that contains a first address code;

a first transmitter operable to wirelessly transmit a return signal;

a first control unit operable to compare a second address code stored in a first memory unit with the address code contained in the locator signal, and activate the first transmitter to wirelessly transmit the return signal if the two codes are the same, wherein the first control unit is linked to the first memory unit, the first receiver, and the first transmitter; and

a first timer linked to the first receiver and the first control unit, the first timer operable to activate the first receiver and first control unit at a specified time interval and for a specified time period;

entering and storing the first address code in a locator unit, the locator unit comprising;

a second memory unit operable to store the first address code;

a user control operable to allow a user to input the first address code and select the first address code after it has been entered and stored;

a second transmitter operable to wirelessly transmit the locator signal, wherein the locator signal includes the selected first address code;

a second receiver operable to receive the return signal transmitted by the transceiver module;

one or more antennas linked to the second receiver;

a second control unit operable to calculate a relative direction of the transceiver module from the locator module, wherein the second control unit is linked to the second memory unit, the user control, the second transmitter, and the second receiver;

selecting the first address stored in the locator unit; and

activating the locator unit to wirelessly transmit the first address code to the transceiver, wherein if the transceiver receives the locator signal containing the first address code and verifies that the first address code matches the second address code stored in the transceiver, the return signal is sent from the transceiver to the locator module, and the locator module analyzes the return signal to determine the relative direction of the transceiver.

46. The method of claim 45, wherein the locator unit further comprises a second timer operable to determine a time between when the locator signal is transmitted to when the return signal is received, wherein the second timer is linked to the second control unit, and wherein the second control unit operable to calculate a distance of the transceiver module from the locator module.

47. The method of claim 45, wherein the first timer activates the first receiver and the first control unit for a period of time at regular intervals.

48. The method of claim 45, wherein the first timer is a real-time clock, and the user can program the real time clock to activate the first receiver and the first control unit at predetermined times.

49. A system, comprising:

a locator module comprising;

a first radio frequency transmitter operable to transmit a first address code;

a first receiver configured to receive a return signal transmitted by a second transmitter;

an antenna array operably connectable to the first transmitter and the first receiver by a switch; and

a first control unit operable to control the switch, the first control unit operable to determine the bearing of a transceiver module from the control unit; and

the transceiver module comprising;

a second receiver operable to receive the signal transmitted by the first transmitter;

the second transmitter operable to transmit the return signal;

a second control unit operable to compare the first address code transmitted by the locator module with an address code stored in the transceiver module and activate the second transmitter to transmit the return signal if the two codes match; and

a timer operable to activate the second receiver and second control unit at a specified time interval and for a specified time period.

50. The system of claim 49, wherein the first control unit is further operable to determine a distance between the locator unit and the transceiver module.

51. The system of claim 49, wherein the first control unit is further operable to calibrate and store a signal processing time delay through the transceiver module.

52. The system of claim 49, wherein calculating the distance of the transceiver module from the locator module comprises determining a phase delay between a transmitted tone frequency modulated onto a first carrier and a received tone frequency modulated onto a second carrier.

53. The system of claim 49, wherein the locator module determines range to the transceiver module by commutating between antennas in the antenna array according to a commutation frequency selected to minimize a tone output from said first receiver.

54. The system of claim 49, wherein the locator module determines range to the transceiver module by switching between antennas in the antenna array according to a commutation frequency selected to minimize a tone output from said first receiver, wherein said commutation frequency is swept across a desired range of frequencies.

55. The system of claim 49, wherein the locator module is configured to measure a phase delay between a tone transmitted to the transceiver module and a tone received from the transceiver module.

56. The system of claim 49, wherein the locator module is configured to calibrate to the transceiver module, the locator configured to:

measure a phase delay between a tone transmitted to the transceiver module and a tone received from the transceiver module when said transceiver module is relatively close to the locator module;

convert the phase delay to a time delay; and

store the transceiver delay time.

57. The system of claim 49, wherein the first control unit controls a commutation rate of said switch.

58. The system of claim 49, wherein said first transmitter sends said first address code using frequency shift keying.

59. The system of claim 49, wherein the locator module further comprises an internal compass unit operable to convert a relative direction of the transceiver module to a magnetic bearing.

60. The system of claim 49, wherein the antenna array comprises two or more antennas coupled to the locator module along an approximately circular path.

61. The system of claim 49, wherein the two or more antennas are pivotally coupled to the locator module.

62. The system of claim 49, wherein the antenna array comprises one or more monopole-type antennas.

63. The system of claim 49, wherein the antenna array comprises one or more dipole-type antennas.

64. The system of claim 49, wherein the antenna array comprises one or more patch-type antennas.

65. The system of claim 49, wherein the first transmitter transmits the first address code using phase shift keying.

66. The system of claim 49, wherein the locator module determines bearing to the transceiver module by commutating between antennas in the antenna array and using Doppler processing to determine a direction of a wireless signal received from the transceiver module.

67. The system of claim 49, wherein the locator module sends commands to said transceiver module.

68. The system of claim 49, wherein the locator signal comprises a spread spectrum signal, an ultra wide band signal, a wideband FM signal, or a CDMA signal.

69. A transceiver comprising:

means for receiving a first frequency band signal containing a transmitted address code;

means for comparing the transmitted address code with a stored address code;

means for transmitting a second frequency band loop-back tone return signal for a specified period of time when said transmitted address code matches said stored address code; and

means for activating the means for receiving at desired intervals.

70. A method for range determination, comprising:

providing an unmodulated carrier signal at a first frequency to a switch, the switch configured to commutate among antennas in a antenna array at a commutation frequency to transmit a first modulated signal modulated according to the commutation frequency;

receiving the modulated signal in a tag receiver, an output of the tag receiver provided to a tag transmitter;

transmitting a second modulated carrier from said tag transmitter, said second modulated carrier modulated according to said commutation frequency;

receiving the second modulated carrier in a second receiver;

adjusting said commutation frequency to minimize an output of the second receiver; and

calculating a distance based on said commutation frequency.

71. A system, comprising:

a locator module comprising;

a first radio frequency transmitter operable to transmit a first address code;

a first receiver configured to receive a return signal transmitted by a second transmitter;

an antenna array operably connectable to the first transmitter and the first receiver by a switch; and

a first control unit operable to control the switch, the first control unit operable to determine the distance of a transceiver module from the control unit; and

the transceiver module comprising;

a second receiver operable to receive the signal transmitted by the first transmitter;

the second transmitter operable to wirelessly transmit the return signal;

a second control unit operable to compare the first address code transmitted by the locator module with an address code stored in the transceiver module and activate the second transmitter to wirelessly transmit the return signal if the two codes match; and

a timer operable to activate the second receiver and second control unit at a specified time interval and for a specified time period.

72. A system, comprising:

a locator module comprising;

a first radio frequency transmitter operable to transmit a first address code;

a first receiver configured to receive a return signal transmitted by a second transmitter;

an antenna array operably connectable to the first transmitter and the first receiver by a switch; and

a first control unit operable to control the switch, the first control unit operable to determine the bearing of a transceiver module from the control unit and operable to detect the presence of multipath by examining a second harmonic of a commutation frequency of the antenna arrays and

the transceiver module comprising;

a second receiver operable to receive the signal transmitted by the first transmitter;

the second transmitter operable to wirelessly transmit the return signal;

a second control unit operable to compare the first address code transmitted by the locator module with an address code stored in the transceiver module and activate the second transmitter to wirelessly transmit the return signal if the two codes match.