Spin-Around Locator

• US 20070194923A1
• Filed: 02/21/2007
• Published: 08/23/2007
• Est. Priority Date: 02/21/2006
• Status: Active Grant

• Current Assignee: Santa Mionica Semiconductor
• Original Assignee: RoundTrip, LLC
• Inventors: Karr, Lawrence
• Granted Patent: US 7,791,470 B2
• Time in Patent Office: Days
• US Class Current: 340/572.1
• CPC Class Codes: G01S 13/589 measuring the velocity vector
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 3/52 using a receiving antenna moving, or appearing to move, in a cyclic path to produce a Doppler variation of frequency of the received signal
• CPC Class Codes: G08B 21/023 Power management, e.g. system sleep and wake up provisions
• 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 21/0266 System arrangements wherein the object is to detect the exact distance between parent and child or surveyor and item
• CPC Class Codes: G08B 21/0275 Electronic Article Surveillance [EAS] tag technology used for parent or child unit, e.g. same transmission technology, magnetic tag, RF tag, RFID

Abstract

A hand-held remote locator (RL) device is used to locate a transponder or micro-transponder (MT). The user activates the RL to transmit a multi-frame ping to the MT in a slow ping mode, where the MT transmits reply messages when the multi-frame ping is received The RL calculates a distance between the RL and the MT using the time-of-flight (TOF) between the transmission of a ping and the receipt of a reply. The user can then engage a fast ping mode, where the RL transmits the multi-frame ping at an increased rate. The user then extends the RL device away from their body and turns through at least a partial arc length about their center line such that data is collected including compass readings, Doppler information, and distance calculations. The directional location for the MT is determined by the RL using the collected data.

Claims

1. A portable remote locator device that is operated by a user to determine a relative distance and direction from the portable remote locator device to an object that is tagged with a transponder, the portable remote locator device comprising:

an input device that is arranged to accept user initiated input;

a time control circuit that is arranged to provide timing control signals according to an internal clock of the portable remote locator device;

an indication means that is arranged to report information to the user;

a transmitter means that is arranged to transmit a structured transmission to the transponder when activated, wherein the structured transmission has a transmit cadence and frequency that is determined by the internal clock, wherein the structured transmission is coded with an identifier recognized by the transponder;

a receiver means that is arranged to capture samples when activated;

a correlator that is arranged to identify a correlation and a correlation phase in response to captured samples from the receiver means;

a means for determining a rotational position associated with the portable remote locator device about an axis that is approximately centered about the user of the portable remote locator device; and

a processor means that is arranged in cooperation with the input circuit, the time control circuit, the indication means, the transmitter means, the receiver means, the correlator, and the means for determining a rotational position, wherein the processor means is arranged to initialize the portable remote locator device in a slow ping mode, wherein in the slow ping mode the processor means is arranged for;

initiating the transmission of a first structured multi-frame transmission to the transponder device at a first time,

detecting a first reply from the transponder device at a second time when the received samples correlate with an expected first reply transmission;

measuring a distance between the portable remote locator device and the transponder based on a difference between the second time and the first time;

wherein the processor means is also arranged to operate the portable remote locator device in a fast ping mode, wherein in the fast ping mode the processor means is arranged to collect a stream of measurements over multiple communications with the transponder in the fast ping mode by repeatedly;

initiating the transmission of a second structured multi-frame transmission to the transponder device at a third time;

detecting a second reply from the transponder device at a fourth time when the received samples correlate to an expected second reply transmission;

measuring a distance between the portable remote locator device and the transponder based on a difference between the third time and the fourth time;

monitoring the correlation phase and rotational position associated with each received sample from the second reply;

determining whether a complete rotation has been successfully completed by the user based on the monitored rotational position;

terminating the fast ping mode when either a complete rotation has been successfully completed or a timeout condition is detected by the processor means; and

wherein the processor means is also arranged to determine the distance and direction to the remote locator after the fast ping mode has terminated by evaluating the stream of measurements., wherein the stream of measurements corresponds to the collection of phases, correlation phase, rotational positions, signal strengths, distance,,

2. The portable remote locator device of claim 1, the input device comprising an interrupt signal, a wake-up timer, a keyboard device, a keypad device, a button, a key, a touch-screen, a touch-panel, a joystick device, a joy-pad device, a mouse device, a pointing device, a touch-pad device, a pressure sensitive input device, another processor, or an input generated by a software program.

3. The portable remote locator device of claim 1, the input device comprising an audio input processor that is arranged to process sound as the user input.

4. The portable remote locator device of claim 3, the audio input processor comprising either an analog to digital-converter (ADC) circuit or a coder-decoder (CODEC) circuit.

5. The portable remote locator device of claim 3, the audio input processor comprising a voice input means.

6. The portable remote locator device of claim 3, the indication means comprising an audio output circuit that is configured to provide an audible alert to the user, wherein the audio output circuit includes an audio output processor that is combined in function with the audio input processor.

7. The portable remote locator device of claim 1, the indication means comprising an audio output circuit that is configured to provide audible information to the user.

8. The portable remote locator device of claim 7, wherein the audio output circuit comprises either:

an audio output device, an audio output processor, or a combination of the audio output device and the audio output processor.

9. The portable remote locator device of claim 7, wherein the audio output circuit comprises either a speaker device, a piezo device, or an audio output port that is accessible by the user.

10. The portable remote locator device of claim 7, wherein the audio output circuit comprising either an analog to digital-converter (ADC) circuit or a coder-decoder (CODEC) circuit.

11. The portable remote locator device of claim 7, the audio output circuit is arranged to playback sounds from either a previously recorded sound or a user recorded sound.

12. The portable remote locator device of claim 7, wherein the audio output circuit is arranged to synthesize previously selected sounds.

13. The portable remote locator device of claim 1, the indication means comprising a visual output circuit that is configured to provide visual information to the user.

14. The portable remote locator device of claim 13, wherein the visual information comprises at least one of:

a graphical distance indication, an alphanumeric distance indication, a graphical direction indication, and an alphanumeric direction indication.

15. The portable remote locator device of claim 1, the visual output circuit comprising at least one of:

an LED type display, an LCD type display, an active display, a passive display, a black and white display, a monochromatic display, a color display, a discrete arrangement of LEDs, a seven segment display, and a light emitting device.

16. The portable remote locator device of claim 1, wherein the visual output circuit and the input device are combined in a touch screen device.

17. The portable remote locator device of claim 1, wherein the means for determining the rotational position comprises at least one of:

an analog compass sensor device, a digital compass sensor device, and an analog-to-digital converter that is arranged to work with the analog compass sensor device.

18. The portable remote locator device of claim 1, wherein the processor means comprises at least one of:

a micro-processor, a micro-controller, a complex instruction set computer (CISC) processor, a reduced instruction set computer (RISC) processor, an application specific integrated circuit (ASIC), a programmable logic device (PLD), a mode control logic, a firmware, a software, a storage circuit, a memory circuit, a non-volatile memory (NVM), and a read-only memory (ROM).

19. The portable remote locator device of claim 1, wherein the processor means is further arranged to encode a message for the transponder in the structured transmission.

20. The portable remote locator device of claim 19, wherein encoded message includes an instruction for the transponder to change to a fast ping mode, where the transponder will repeatedly transmit reply messages to the portable remote locator device.

21. The portable remote locator device of claim 19, wherein encoded message includes an instruction for the transponder to change to a bookkeeping mode, where the transponder will encode information in a reply message that is transmitted to the remote locator.

22. The portable remote locator device of claim 19, wherein the encoded information in the reply message includes at least one of:

an estimated battery life associated with the transponder, environmental sensor data for the transponder, an ambient temperature, an ambient pressure, biological sensor data associated with the transponder, a heart rate, a blood pressure, a receiver signal quality, and a receiver signal strength.

23. The portable remote locator device of claim 1, wherein the processor means is further arranged to:

initiate a mode change to a fast ping mode after providing notification to the user, wherein the transmitter means in the portable remote locator device is arranged to transmit at an increased rate during the fast ping mode;

activate the transmitter means during the initiation of the fast ping mode, wherein the mode change to the fast ping mode is encoded in a message that is transmitted to the transponder at a third time so that the transponder will reply at an increased rate during the fast ping mode.

24. The portable remote locator device of claim 23, wherein the processor means is further arranged to initiate a user notification via the indication means when the direction associated with the location of the transponder relative to the portable remote locator device is determined.

25. The portable remote locator device of claim 24, wherein the indication means is arranged to provide a visual indicator of the determined direction.

26. The portable remote locator device of claim 25, wherein the visual indicator comprises at least one of:

a graphical distance indication, an alphanumeric distance indication, a graphical direction indication, and an alphanumeric direction indication.

27. The portable remote locator device of claim 1, wherein the processor means is further arranged to detect the timeout condition when insufficient reply messages are received at the fourth time that correlates with the expected second reply transmission.

28. The portable remote locator device of claim 24, wherein the processor means is further arranged to:

initiate a mode change to a slow ping mode after determining the direction, wherein the transmitter means in the portable remote locator device is arranged to transmit at a decreased rate during the slow ping mode;

activate the transmitter means during the initiation of the slow ping mode, wherein the mode change to the slow ping mode is encoded in a message that is transmitted to the transponder at a fifth time so that the transponder is expected to reply to the decreased rate of transmissions from the remote locator;

monitor the distance between the portable remote locator device from the means for determining the rotational position at the fourth time; and

update the visual indicator via the indication means.

29. The portable remote locator device of claim 21, wherein the portable remote locator device is arranged to activate a sleep mode when either inactive for a predetermined time interval, or when the transponder fails to reply within a designated time.

30. The portable remote locator device of claim 1, further comprising at least two antennas that are arranged for receiving reply transmissions in the fast ping mode, wherein the processor is further arranged to the received samples from each antenna is monitored, and wherein the stream of measurements includes the identified antenna associated with the received samples.

31. A transponder device that is arranged to communicate with a remote locator device such that the remote locator device can determine a relative location of an object that is tagged with the transponder, the transponder device comprising:

a time control circuit that is arranged to provide timing control signals according to an internal high frequency clock for the transponder device;

a receiver means that is arranged to capture samples when activated utilizing timing signals from the internal high frequency clock of the transponder device;

a correlator that is arranged to identify a correlation and a correlation phase in response to captured samples from the receiver means;

a transmitter means that is arranged to transmit a structured reply transmission to the remote locator when activated, wherein the structured reply transmission has a transmit cadence and frequency that is determined by a synthesized timing that is derived from the captured samples such that reply transmissions from the transmitter means has a transmit cadence and frequency that is substantially matched to an expected reply cadence and frequency based on an internal clock for the remote locator device;

a processor means that is arranged in cooperation with the time control circuit, the transmitter means, the receiver means, and the correlator means, wherein the processor means is arranged to control an operating mode associated with the transponder, wherein the operating mode corresponds to one of a slow poll sleep mode, and a fast poll sleep mode, wherein the processor means is arranged to deactivate the high frequency clock until either the receiver means or the transmitter means is activated, wherein during the sleep mode the processor means is arranged to;

periodically enable the receiver means to capture samples during a first capture interval according to a first period that repeats after a long time interval;

evaluate the captured samples acquired during the first capture interval, identify a first authentication method when the captured samples from the first capture interval correlate to a validly coded message from the remote locator;

transmit a first reply message to the remote locator with the transmitter when the first authenticated message is identified; and

change the operating mode to the fast poll sleep mode when the first authenticated message is identified unless the first authenticated message includes a command from the remote locator to select a different mode from the fast poll sleep mode; and

wherein during the fast poll sleep mode the processor means is arranged to;

periodically enable the receiver means to capture samples during a second capture interval according to a second period that repeats after a short time interval;

evaluate the captured samples from the output of the receiver during the second capture interval;

identify a second authenticated message when the captured samples from the second capture interval correlate to another validly coded second message from the remote locator;

transmit a second reply message to the remote locator when the second authenticated message is identified, and change the operating mode to the slow poll sleep mode when a timeout interval expires without identifying the second authenticated message.

32. The transponder device of claim 31, wherein the processor means comprises at least one of:

a micro-processor, a micro-controller, a complex instruction set computer (CISC) processor, a reduced instruction set computer (RISC) processor, an application specific integrated circuit (ASIC), a programmable logic device (PLD), a mode control logic, a firmware, a software, a storage circuit, a memory circuit, a non-volatile memory (NVM), and a read-only memory (ROM).

33. The transponder device of claim 31, wherein the processor means is further arranged to decode a message from the remote locator from the captured samples.

34. The transponder device of claim 33, wherein the decoded message includes an instruction to change the operating mode to one of the slow poll sleep mode and the fast poll sleep mode.

35. The transponder device of claim 33, wherein the decoded message includes an instruction for the transponder to change to a bookkeeping mode.

36. The transponder device of claim 33, wherein the processor is arranged to encode data associated with the bookkeeping mode for transmission to the remote locator.

37. The transponder device of claim 35, wherein the bookkeeping mode corresponds to a monitoring operation associated with at least one of:

an estimated battery life associated with the transponder, environmental sensor data for the transponder, an ambient temperature, an ambient pressure, biological sensor data associated with the transponder, a heart rate, a blood pressure, a receiver signal quality, and a receiver signal strength.

38. The transponder device of claim 31, wherein the processor is further arranged to change the operating mode to a high-frequency clock mode when the second authenticated message is identified unless the second authenticated message includes a command from the remote locator to select a different mode from the high-frequency clock mode.

39. The transponder device of claim 38, wherein the processor is further arranged to, during the high frequency clock mode, periodically enable the receiver means to capture samples during a third capture interval according to a third period that is precisely aligned in time with an expected time of arrival for transmissions from the remote locator, wherein the third period repeats after a very short time interval, evaluate captured samples from the output of the receiver during the third capture interval, identify a third authenticated message when the captured samples from the third period are identified as a validly coded third message from the remote locator, transmit a third reply message to the remote locator when the third authenticated message is identified.

40. The transponder of claim 39, wherein the processor is further arranged to change the operating mode to a slow poll sleep mode when a second timeout interval expires without identifying the third authenticated message.

41. A method for a portable remote locator device that is operated by a user to determine a relative location of an object that is tagged with a transponder device, the method comprising:

activating the portable remote locator device in an initial acquisition mode in response to user initiated input;

during the initial acquisition mode;

transmitting a first structured transmission to the transponder device over a first time interval when the initial acquisition mode is active, wherein the first structured transmission is coded with an identifier recognized by the transponder;

capturing samples with a receiver during the first time interval;

detecting a first reply from the transponder device at a second time when the captured samples correlate with an expected first reply transmission from the remote locator; and

changing the operating mode of the portable remote locator device from the initial acquisition mode to a spin-around mode when the first reply is detected;

notifying the user to rotate the portable remote locator device when the operating mode changes from the initial acquisition mode to the spin-around mode;

collecting a stream of measurements over multiple communications with the transponder during the spin-around mode by repeatedly;

transmitting a second structured transmission to the transponder over a third time interval, wherein the first structured transmission is coded with an identifier recognized by the transponder;

capturing samples with the receiver and corresponding directional readings from an electronic compass during a fourth time interval;

detecting a second reply from the transponder when the captured samples from the fourth time interval correlate to an expected second reply transmission from the transponder device, and capturing the correlation data;

determining whether a complete rotation has been successfully completed by the user based on the captured readings from the electronic compass;

terminating the spin-around mode when either a complete rotation of the portable remote locator device is successfully completed; and

determining a directional heading from the portable remote locator device to the transponder by evaluating the stream of measurements after the spin-around mode is terminated; and

updating a user direction indicator on the portable remote locator device when the valid directional reading is identified.

42. A method for a transponder to communicate with a remote locator such that a directional heading from the remote locator to the transponder can be determined, the method comprising:

activating a high frequency clock in the transponder when the transponder is operated in either a slow poll mode, or a fast poll mode;

deactivated the high frequency clock in the transponder when the transponder is operated in a sleep interval;

periodically activating the sleep interval for the transponder after a first time interval expires when the slow poll mode is active, wherein a wake-up time for the sleep interval is sufficiently long such that the transponder consumes minimal power during the low-power sleep mode;

periodically activating the sleep interval for the transponder after a second time interval expires when the fast poll mode is active, wherein a wake-up time for the sleep interval is shorter for the fast poll mode than for the slow poll mode;

capturing samples with a receiver in the transponder when the high frequency clock is active;

correlating captured samples with an expected transmission from the remote locator when the high frequency clock is active;

synthesizing a timing and cadence for transmissions in the transponder with timing information acquired from the captured samples when a valid correlation is identified;

changing from the slow poll mode to the fast poll mode when a fast mode command is extracted from the captured samples during the slow poll mode;

changing from the fast poll mode to the slow poll mode when a slow poll mode command is extracted from the captured samples during the fast poll mode, or when the fast poll mode is active for an extended time period without receiving a slow poll mode command; and

transmitting a reply message to the remote locator using the synthesized timing and cadence when the captured samples correlate with the expected transmission from the remote locator.