WO2006098791A2 - System and method for locating objects and communicating with the same - Google Patents
System and method for locating objects and communicating with the same Download PDFInfo
- Publication number
- WO2006098791A2 WO2006098791A2 PCT/US2005/046333 US2005046333W WO2006098791A2 WO 2006098791 A2 WO2006098791 A2 WO 2006098791A2 US 2005046333 W US2005046333 W US 2005046333W WO 2006098791 A2 WO2006098791 A2 WO 2006098791A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- transmission
- signal
- code
- pattern
- phase
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims description 89
- 230000004044 response Effects 0.000 claims abstract description 10
- 230000005540 biological transmission Effects 0.000 claims description 326
- 239000000872 buffer Substances 0.000 claims description 16
- 230000010363 phase shift Effects 0.000 claims description 14
- 230000001133 acceleration Effects 0.000 claims description 12
- 230000002596 correlated effect Effects 0.000 claims description 11
- 230000006870 function Effects 0.000 claims description 11
- 230000001427 coherent effect Effects 0.000 claims description 10
- 238000009825 accumulation Methods 0.000 claims description 9
- 238000011156 evaluation Methods 0.000 claims description 8
- 238000005259 measurement Methods 0.000 claims description 8
- 230000008859 change Effects 0.000 claims description 7
- 230000007246 mechanism Effects 0.000 claims description 6
- 230000036772 blood pressure Effects 0.000 claims description 4
- 230000000875 corresponding effect Effects 0.000 claims description 4
- 230000001953 sensory effect Effects 0.000 claims description 4
- 230000036760 body temperature Effects 0.000 claims description 3
- 238000012937 correction Methods 0.000 claims description 3
- 239000000284 extract Substances 0.000 claims description 3
- 230000033764 rhythmic process Effects 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims description 3
- 230000008054 signal transmission Effects 0.000 claims description 3
- 230000002194 synthesizing effect Effects 0.000 claims 5
- 238000001514 detection method Methods 0.000 claims 2
- 230000004962 physiological condition Effects 0.000 claims 2
- 238000007670 refining Methods 0.000 claims 2
- 238000000638 solvent extraction Methods 0.000 claims 2
- 230000003213 activating effect Effects 0.000 claims 1
- 238000012545 processing Methods 0.000 description 36
- 238000004891 communication Methods 0.000 description 20
- 230000033001 locomotion Effects 0.000 description 12
- 239000013078 crystal Substances 0.000 description 9
- 230000008569 process Effects 0.000 description 9
- 238000004458 analytical method Methods 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 8
- 230000010354 integration Effects 0.000 description 8
- 125000004122 cyclic group Chemical group 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 238000001228 spectrum Methods 0.000 description 4
- 238000007792 addition Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 230000001413 cellular effect Effects 0.000 description 3
- 238000013459 approach Methods 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000003139 buffering effect Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 239000011664 nicotinic acid Substances 0.000 description 2
- 238000003672 processing method Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 230000003252 repetitive effect Effects 0.000 description 2
- 238000012163 sequencing technique Methods 0.000 description 2
- 230000011664 signaling Effects 0.000 description 2
- 238000010897 surface acoustic wave method Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 238000010200 validation analysis Methods 0.000 description 2
- 101150083341 LOG2 gene Proteins 0.000 description 1
- 108010076504 Protein Sorting Signals Proteins 0.000 description 1
- 238000005314 correlation function Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 210000003127 knee Anatomy 0.000 description 1
- 230000003278 mimic effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 210000000352 storage cell Anatomy 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/74—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
- G01S13/76—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems wherein pulse-type signals are transmitted
- G01S13/765—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems wherein pulse-type signals are transmitted with exchange of information between interrogator and responder
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/87—Combinations of radar systems, e.g. primary radar and secondary radar
- G01S13/878—Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector
Definitions
- the present disclosure relates generally to a system and method of locating an object. More particularly, the present disclosure relates to a system and method for locating a living being.
- the living being may be located with a bionic device that is implanted therein for the purposes of tracking location.
- a missing vehicle locator system is described in US Patent No. 5,418,736 issued to Bird.
- the vehicle locator system uses one or more GPS systems in conjunction with a GPS antenna, a receiver/transmitter, a telephone with associated antennas, and a modem mounted in a vehicle whose position is to be monitored.
- a paging request is issued and received by a paging responder in the vehicle.
- the paging request causes the modem to interrogate the GPS receiver to determine the current position of the vehicle.
- the current position of the vehicle is transmitted via a cellular telephone link to notify a vehicle location service center of the current location of the vehicle.
- Other known location determination techniques include the use of a Loran or a Glonass satellite based system.
- US Patent No. 5,576,716 to Sadler for locating lost or stolen property.
- This location system includes a GPS module, a microcomputer, a modem, and a telephone, all of which must be installed in the vehicle.
- the system described regularly and automatically computes the position of the property for transmission via the phone link to a central receiver/transmission station.
- the present disclosure is related to a system and method of locating an object. More particularly, the present disclosure relates to a system, apparatus and method for locating a living being.
- a remote locator (RL) is arranged to communicate with a transponder or micro-transponder (MT) for determining the location of the MT.
- the transponder device may be a wearable device, bionically implanted in a living being, attached to an object, or embedded in some object.
- the RL and the MT each include a transmitter and a receiver.
- An asymmetric cooperative protocol is used, where the MT's response to a RL's inquiry is coherent with respect to the received locator signal.
- the RL emits a relatively powerful signal with a repeating sequence.
- the MT correlates an internal ID code against incoming signals and/or noise.
- the MT emits a synthesized response coherent with the received signal.
- the RL cyclically integrates multiple response sequences received from the MT, allowing low transmission power in the MT.
- the RL correlates the integrated response, determines round-trip Doppler and time-of-flight, and computes the distance and angle to the MT.
- the MT can be a wearable device, bionically implanted, attached to an object, or embedded in some object.
- the RL may be arranged to initiate a transmission sequence that includes transmission signals that are encoded with a unique identifier that is associated with the MT.
- the coded transmission is broken into frames that include sufficient information to identify clock and timing recovery simultaneous with transfer of information and validation signals.
- the MT can be arranged to operate in a sleep mode to conserve power. Periodically, the MT is activated out of the sleep mode to capture signals that can be noise and/or signals from the RL's transmissions. A variety of signal processing functions are performed on the captured signals to validate that the transmission is received by the intended MT. Frequency and phase information is initially recovered from one portion of the transmission, and further refined using a bootstrapping process. Timing location within the frame (e.g., coarse timing) is recovered in another portion of the transmission.
- phase and frequency are recovered, data reception is scheduled with a degree of certainty.
- the data is extracted and a reply message is transmitted from the MT back to the RL, where similar signal processing functions are performed.
- the carefully corrected round-trip time of the transmission sequence is used to identify distance between the RL and the MT.
- a round-trip Doppler shift, that is independent of the MT clock, is measured to and correlated against the relative motion of the RL and MT to assess the directional vector from the RL to the MT.
- the RL includes one, two, or more antennas that arranged to resolve the direction ambiguity associated with the evaluated Doppler shift.
- two antennas are physically spaced apart from one another and the arrival time for reception between the two antennas is identified.
- a measured acceleration vector such as from an accelerometer in the RL is used with the arrival times to resolve the directional ambiguity.
- three antennas are included in the RL and the receive times associated with the three antennas are used to resolve the directional ambiguity.
- the antennas are spaced apart along an axis that is perpendicular to the direction of travel for the RL such that the first antenna that receives an identifiable signal resolves which side of the RL the MT is located relative to the direction of travel (e.g., on the right side of the RL or the left side of the RL).
- the presently described system has the ability to identify location of a MT with a RL utilizing an asymmetric transmission system.
- the signals captured by the MT will typically not be aligned in time with the start and end of a complete pattern in the sequence (e.g., a 2047 chip sequence).
- the RL is arranged to transmit repeated patterns over time in the sequence.
- the MT is arranged to captures signals over a sufficient length of time to capture a complete pattern in the sequence, even though the captured pattern may be rotated in time relative to the start and end of a complete pattern.
- a circular correlator can be used to evaluate the captured signals such that the captured signals are properly identified with the specific MT, despite the rotation status of the pattern.
- a circular correlation is a correlator that operates on a sequence of fixed length, where the sequence may be circularly shifted in time such that the beginning of the original sequence may be received in the shifted sequence after the end of the original sequence. While a general correlator may not give valid timing information, the circular correlation will provide valid timing information when the captured signals are not aligned in time with the start and end of a complete pattern.
- the signals captured by the MT will typically not comprise a neat period of the sequence (e.g., a 2047 chip sequence).
- the MT Since the MT does not have a priori knowledge of the timing related to transmission and reception from the RL, circular correlations of the received transmissions are used by the MT to determine the fine and coarse timing. While a general correlator may not give valid timing information, the circular correlation will provide valid timing information when the captured signals are not in a neat period.
- the presently described asymmetric transmission system can be configured such that the MT receives a relatively high power transmission of a structured signal from the RL, while the reply or acknowledgement transmission from the MT to the RL is a very low power transmission.
- An example MT is configured to operate in a very low power "inactive" mode or “sleep mode", where the MT "activates” or “wake-ups” for brief intervals to listen for the transmission from the RL.
- the MT correlates each piece of its received structured signals to determine if these signals are coded with an identification code (ID Code) that is specifically associated with the MT.
- ID Code identification code
- the MT also determines the precise frequency, timing, phase, and cadence for which a reply transmission can be transmitted back to the RL from the received structured signals.
- the reply transmission that is transmitted from the MT to the RL is a very low power transmission of short duration (a short structured signal) such that significant battery life is conserved.
- the reply transmission is a very low power transmission
- the MT is arranged to utilize an integration and circular correlation technique to increase the signal-to-noise level of the captured reply transmission.
- a reply transmission signal is transmitted back to the RL from an MT, where the MT synthesizes timing, frequency, phase, and cadence for the reply transmission from signals that are received by the MT from the RL.
- the frequency of the reply transmission from the MT differs from the original frequency from the RL's transmission by a Doppler shift (ignoring other noise and minor error sources).
- the RL can predict the reply transmission frequency with a very small margin of error.
- the potential uncertainty of the reply transmission frequency is small enough so that the phase rotation over several tens of transmission sequences is much less than one turn (one phase rotation through 360 degrees).
- FIGS. IA and IB illustrate an example communication system that includes a remote locator (RL) and a micro-transponder (MT);
- RL remote locator
- MT micro-transponder
- FIGS. 1C, ID and IE illustrate various example mechanisms to resolve directional ambiguities between a RL and a MT;
- FIG. 2 illustrates an example transmitter;
- FIG. 3 is a diagram illustrating a set of frames formatted for transmission
- FIGS. 4A and 4B are diagrams illustrating the timing acquisition for an example communication system
- FIGS. 5 A - 5B are example diagrams for example receivers;
- FIG. 6 is a flow-chart for an example transmitter;
- FIGS. 7A-7B, 8A-8B, and 9 are flow-charts for example receivers, arranged in accordance with at least one aspect of present disclosure.
- connection means a direct electrical connection between the things that are connected, without any intermediary devices.
- coupled means either a direct electrical connection between the things that are connected or an indirect connection through one or more passive or active intermediary devices.
- circuit means one or more passive and/or active components that are arranged to cooperate with one another to provide a desired function.
- signal means at least one current signal, voltage signal, electromagnetic wave signal, or data signal.
- the present disclosure is related to an apparatus, system, and method for communicating between a remote locator (RL) and a micro-transponder (MT).
- Communication between a RL and a MT is used to determine a location of the MT.
- the MT and the RL each include a receiver and a transmitter.
- the communication signals from the transmitters are encoded with a unique ID code.
- the communication signal consists of a sequence of encoded transmissions, where each sequence is arranged to provide a portion of clock synchronization and calibration information.
- Each receiver validates the ID code for the transmission, and decodes information.
- the frequency, phase, and starting time of the coded transmission sequence is determined by the transmission sequence itself such that clock recovery can be performed without additional information.
- the MT can be a wearable circuit such as a watch, affixed to an object, embedded in an object, or an implantable bionic device.
- Frequency and phase information in the MT is initially recovered from one portion of the transmission from the RL, and further refined using a bootstrapping process.
- Timing location within the frame e.g., coarse timing
- phase and frequency are recovered, data reception can be scheduled with a degree of certainty.
- the data is extracted and a reply message is transmitted from the MT back to the RL, where similar signal processing functions are performed.
- the carefully corrected round-trip time of the transmission sequence is used to identify distance between the RL and the MT.
- a synthetic round-trip Doppler shift which is independent of the MT's internal clock, is measured to and correlated against the relative motion of the RL and MT to assess the magnitude of a directional vector between the RL to the MT.
- the RL includes one, two, or more antennas that arranged to resolve the direction ambiguity associated with the evaluated Doppler shift.
- two antennas are physically spaced apart from one another and the arrival time for reception between the two antennas is identified.
- a measured acceleration vector such as from an accelerometer in the RL is used along with the identified arrival times to resolve the directional ambiguity.
- the three antennas are included in the RL and the receive times associated with the three antennas are used to resolve the directional ambiguity.
- the presently described system has the ability to identify location of a MT with a RL utilizing an asymmetric transmission system.
- the signals captured by the MT will typically not be aligned in time with the start and end of a complete pattern in the sequence (e.g., a 2047 chip sequence).
- the RL is arranged to transmit repeated patterns over time in the sequence.
- the MT is arranged to captures signals over a sufficient length of time to capture a complete pattern in the sequence, even though the captured pattern may not be rotated in time relative to the start and end of a complete pattern.
- a circular correlator can be used to evaluate the captured signals such that the captured signals are properly identified by the MT, despite the rotation status of the pattern.
- a circular correlation is a correlator that operates on a sequence of fixed length, where the sequence may be circularly shifted in time such that the beginning of the original sequence may be received in the shifted sequence after the end of the original sequence. While a general correlator may not give valid timing information, the circular correlation will provide valid timing information when the captured signals are not aligned in time with the start and end of a complete pattern.
- the presently described asymmetric transmission system can be configured such that the MT receives a relatively high power transmission of a structured signal from the RL, while the reply or acknowledgement transmission from the MT to the RL is a very low power transmission.
- An example MT is configured to operate in a very low power "inactive" mode or “sleep mode", where the MT "activates” or “wake-ups” for brief intervals to listen for the transmission from the RL.
- the MT correlates each piece of its received structured signals to determine if these signals are coded with an identification code (ID Code) that is specifically associated with the MT.
- ID Code identification code
- the MT also determines the precise frequency, timing, phase, and cadence for which a reply transmission can be transmitted back to the RL from the received structured signals.
- the reply transmission that is transmitted from the MT to the RL is a very low power transmission of short duration (a short structured signal) such that significant battery life is conserved.
- the reply transmission is a very low power transmission
- the MT is arranged to utilize an integration and circular correlation technique to increase the signal-to-noise level of the captured reply transmission.
- a reply transmission signal is transmitted back to the RL from an MT, where the MT synthesizes timing, frequency, phase, and cadence for the reply transmission from signals that are received by the MT from the RL.
- the frequency of the reply transmission from the MT differs from the original frequency from the RL's transmission by a Doppler shift (ignoring other noise and minor error sources).
- the RL can predict the reply transmission frequency with a very small margin of error.
- the potential uncertainty of the reply transmission frequency is small enough so that the phase rotation over several tens of transmission sequences is much less than one turn (one phase rotation through 360 degrees).
- FIGS. IA and IB illustrate an example communication system that includes a RL and a MT arranged in according with at least one aspect of the present disclosure.
- the RL is arranged to transmit a sequence over a first communication channel (COM13), while the MT is arranged to transmit back to the RL via two communication channels (COM31 and COM32).
- the example RL device includes a first antenna (ANTl) that is coupled to a first transmit/receive switch (SWl).
- the first transmit/receive switch (SWl) is coupled to a first transmitter (TXTRl) and a first receiver (RCVRl) in response to a first control signal (TX1/RX1N).
- a transmission sequence (TSEQ) is coupled to the first transmitter (TXTRl) when transmission commences, where the sequence is determined by an ID code.
- a second receiver (RCVR2) is coupled to a second antenna (ANT2).
- the first and second receivers (RCVRl, RCVR2) are coupled to the baseband processing and signal analysis block.
- a third antenna (ANT3) may also be coupled to a third receiver (RCVR3), which is also coupled to the baseband processing and signal analysis block.
- Time control is provided to the transmitter, receiver, and a processor in the form of various control signals (TOSC, ROSC and CLK).
- the processor receives inputs and coordinates the operation of the baseband processing, signal analysis, memory buffering, input processing, display processing, and audio processing.
- the memory processing can include random access memory (RAM), readonly memory (ROM, as well as non-volatile memory (NVM) such as Flash memory, battery backed up RAM, EEPROM, as well as other NVM type technologies.
- the example MT device includes a fourth antenna (ANT4) that is coupled to a second transmit/receive switch (S W2).
- the second transmit/receive switch (S W2) is coupled to a second transmitter
- TXTR2 TXTR2 and a fourth receiver (RCVR4) in response to another control signal (TX2/RX2N).
- a reply sequence (RSEQ) is coupled to the second transmitter (TXTR2) when transmission commences, where the sequence is determined by the ID code.
- the fourth receiver (RC VR4) is arranged to provide in-phase and quadrature signals (I and Q) to a capture buffer.
- the capture buffer is coupled to a correlator that can provide both direct form correlation and FFT correlation.
- the FFT correlator is arranged to provide a circular correlation function of the received I/Q data with the complex I/Q data related to the ID code.
- a signal analyzer and a processor are both arranged to receive the data output from the correlator for evaluation.
- Time control is provided to the transmitter, receiver, and the processor in the form of various additional control signals (TCLK, RCLK and CLK).
- the processor receives inputs and coordinates the operation of the correlator, signal analysis, memory buffering, input processing, display processing, and audio processing.
- the memory processing can include random access memory (RAM), read-only memory (ROM, as well as non-volatile memory (NVM) such as Flash memory, battery backed up RAM, EEPROM, as well as other NVM type technologies.
- the present disclosure describes a small device (e.g, a transponder or a micro-transponder) that has a long battery life by suspending energy consumption until operation is required. Since the MT device needs to be in an active state for very brief intervals, the battery life is extended substantially.
- cellular telephone technologies can be used to determine position in conjunction with a global positioning system (GPS) set, the energy required to operate conventional cellular telephones even in a standby mode will rapidly deplete small batteries.
- GPS global positioning system
- a GPS set in such an application would awaken from sleep, and perform a cold start location fix, which process will consume a considerable amount of energy that again rapidly depletes the battery.
- the present disclosure contemplates that a portable location technology is preferably operated intermittently to minimize power consumption, and thus addresses some of the problems from conventional location determination techniques.
- the present disclosure has analyzed and identified problems with current Doppler shift technology such as found in GPS signals.
- GPS signals may be detected efficiently by means of FFT correlation, there are approximately 28 GPS satellites that include a significant level of Doppler ambiguity from about ⁇ 15ppm.
- a Doppler shift of roughly 22KHz maximum requires on the order of several tens of Doppler bins or correlation attempts to identify the Doppler shift.
- the processing efforts necessary to utilize a conventional GPS technology are unacceptable for the presently disclosed use.
- the MT in the current disclosure is searching for a single code, and in addition, need not contend with huge velocities, and thus does not require any Doppler bins.
- the present disclosure describes an apparatus and system that has reduced capture times relative to conventional technologies, where the magnitude of the processing is reduced by approximately two orders of magnitude.
- FIG. IA illustrates an example RL that is arranged to communicate with an example MT.
- the MT is arranged (e.g., by a sleep timer) to wake up at pre-determined intervals and receive a coded transmission signal (e.g., C0M13).
- the coded signals received and evaluated using a variety of signal processing methods such as digital signal processing, analog signal processing, Fast Fourier Transform (FFT), correlation, inverse FFT (IFFT) to name a few.
- FFT Fast Fourier Transform
- IFFT inverse FFT
- various internal signals and parameters are varied such that time, frequency and phase alignments for receiving and transmitting coded information are successively refined (e.g., through digital control mechanisms) for accurate processing.
- the MT using as it's time base the Doppler shifted frequency of the signal from the RL, subsequently transmits a reply sequence back to the RL, which is similarly coded.
- the RL receives the coded transmission, and processes the incoming signals in a similar fashion as the MT.
- the antennas in the RL are physically separated from one another such that, with the measured Doppler shift, it is possible to determine which antenna is physically closer to the MT, resolving the angle ambiguity, and (e.g., via signal analysis and processing) to determine a location vector between the RL and the MT.
- the RL includes a processor that can be any appropriate processing means including but not limited to at least one: micro-processor, micro-controller, CISC processor, RISC processor, application specific integrated circuit (ASIC), to name a few.
- the processor is arranged to: receive and evaluate inputs, control outputs, log data, retrieve logged data, and execute programs.
- the processor is thus arranged to communicate with any number of circuit components such as: a time control circuit, an input circuit, a display circuit, an audio circuit, a storage circuit, and a memory circuit.
- Example inputs can be from any number of sources such as: an interrupt signal, a wake-up timer, a keyboard device, a touch-screen (passive or active), a touch-panel, a joystick device, a mouse device, a touch-pad device, another processor and an input generated by a software program.
- Voice recognition under software control can be used in conjunction with the audio circuit to generate an input.
- the display and audio circuits can be used as an indication means for reporting information to a user of the RL device, as well as to display navigation and location information.
- the storage circuit can be any known storage mechanism such as a magnetic recording device (e.g., a disk drive, a hard disk drive, a tape drive), an optical recording device (e.g., CD, DVD, etc.), to name a few.
- the memory circuit can include a dynamic-type memory (DRAM), a static-type memory (SRAM), a read-only-type memory (ROM), and a non-volatile-type memory (NVM), to name a few.
- DRAM dynamic-type memory
- SRAM static-type memory
- ROM read-only-type memory
- NVM non-volatile-type memory
- the RL is operated to send a transmission that consists of a series of coded signals.
- the code is generated by a unique identifier (e.g., an ID Code) that is associated with a specific MT.
- a sequence generator is arranged to evaluate the unique identifier and create a transmit sequence. After the coded sequence is generated for the unique identifier, additional information is encoded into the transmit sequence. In one example, the additional information can be command/control instructions for the MT. Only one sequence need be transmitted to accomplish communication, timing synchronization, and sequence validation.
- the output of the sequence generator e.g., TSEQ
- LPFl low pass filter
- the transmitter is arranged to carrier modulate (e.g., multi-phase shift keying, binary phase shift keying, quadrature phase shift keying, differential phase shift keying, continuous phase modulation, multiple amplitude and phase shift keying, etc.) the coded signals with a carrier frequency, a spread spectrum carrier, and/or a frequency hopping method.
- the transmit-receive switch (SWl) is arranged to couple the carrier modulated coded signals to the antenna (ANTl) during the transmit sequence.
- a band-limiting filter e.g., BPFl
- BPFl can be provided between the antenna and the transmit-receive switch (SWl) such that out-of-band signals are ignored.
- the band-limiting filter can be any filter that provides reasonable band-limiting functions such as: a passive band-pass filter, an active band-pass filter, a surface acoustic wave (SAW) filter, a bulk acoustic wave (BAW) filter, a comb filter, a strip-line filter, to name a few.
- the RL is operated to receive a transmission from the MT that consists of another series of coded signals.
- the coded signal is similarly generated by the MT with a unique identifier (e.g., the ID Code) that is associated with the specific MT.
- the receiver e.g., RCVRl
- the receiver is arranged to receive carrier modulated (e.g., multi-phase shift keying, binary phase shift keying, quadrature phase shift keying, differential phase shift keying, continuous phase modulation, multiple amplitude and phase shift keying, etc.) coded signals from the antenna (ANTl) via SWl .
- Another receiver e.g., RCVR2
- the two antennas can be multiplexed to a common receiver circuit.
- the received signals are handled by a baseband processor that can also provide signal-processing functions.
- the baseband processor is arranged to provide captured signals to the processor, which is arranged to handle signal-processing functions.
- another band-limiting filter e.g., BPF2
- BPF2 another band-limiting filter
- the described RL performs distance measurement by round trip time measurement.
- the round trip time can be determined by the difference in time between the transmission of a signal from the MT to the RL, and the subsequent reply transmission of an acknowledgement signal from the RL back to the MT, offset by any other delays.
- Bearing to the MT is determined by measuring the velocity or acceleration of the RL, determining the synthetic round-trip Doppler or synthetic differential round-trip Doppler information (e.g., Doppler shift or Doppler acceleration), and providing a signed velocity with the measured velocity or acceleration of the RL.
- Differential Doppler information is relatively insensitive to target motion but not target acceleration.
- the RL's acceleration vector can be measured with a three-axis accelerometer, or with a GPS set when available with a clear view of the sky.
- the position fixes on the MT may have a two-fold ambiguity in location, since for linear motion two angle estimates exist.
- the location ambiguity can be resolved by nonlinear motion (e.g., changing a direction of travel) of the RL relative to the MT, using a single one of the antennae from FIG. IA.
- FIG. 1C An example of a RL that includes one antenna employing non-linear motion is illustrated in FIG. 1C. As illustrated in FIG.
- an antenna (ANTl) in the RL receives a first signal (S 1 ) from a first communication signal (COM311) at a first time (I 1 ) when the RL is moving in a first direction (di).
- the antenna (ANTl) in the RL receives a second signal (S 2 ) from a second communication signal (COM312) at a second time (t 2 ) when the RL is moving in a second direction (d 2 ) that is different from the first direction (di).
- the RL is thus moving along a non-linear motion path between times ti and t 2 .
- a two antenna system requires that at least one of the RL and the MT are moving relative to one another such that it is possible to detect a direction.
- FIG. ID An example of an RL that employs a two antenna system for resolving direction is illustrated in FIG. ID.
- a first antenna (ANTl) in the RL receives a first signal (Si) from a first communication signal (COM31) at a first time (ti) when the RL is moving in a first direction (d ⁇ ).
- a second antenna (ANT2) in the RL receives a second signal (S 2 ) from a second communication signal (COM32) at a second time (t 2 ) when the RL has moved positions along either the same first direction (di) along a linear motion path, or in another direction (not shown) that is along a non-linear motion path.
- the antennas are spaced apart along an axis that is perpendicular to the direction of travel for the RL such that the first antenna that receives an identifiable signal resolves which side of the RL the MT is located relative to the direction of travel (e.g., on the right side of the RL or the left side of the RL).
- the received signal time of one antenna is slightly different from that of the other antenna. Since the closer antenna will have earlier information than the antenna that is further away, such that the location ambiguity can be resolved based on the relative arrival times and the direction of travel of the RL.
- a third antenna that is physically spaced apart from the first and second antennas can be used to resolve the direction ambiguity.
- the third antenna has the added benefit that the location ambiguity can be resolved without any movement required by the RL.
- the third antenna (ANT3) is arranged to cooperate with a third receiver (RCVR3) through a third band-limiting filter (e.g., BPF3) as illustrated in FIG. IA.
- the third antenna may be multiplexed with a single receiver similar to that previously described in the two antenna system described above.
- FIG. IE An example of an RL that employs a three antenna system for resolving direction is illustrated in FIG. IE.
- a first antenna (ANTl) in the RL receives a first signal (Si) from a first communication signal (COM31) at a first time (ti).
- a second antenna (ANT2) in the RL receives a second signal (S 2 ) from a second communication signal (COM32) at a second time (t 2 ).
- a third antenna (ANT3) in the RL receives a third signal (S 3 ) from a third communication signal (COM33) at a third time (t 3 ).
- the received signal times of each antenna are slightly different from one another. By analyzing the arrival times of each antenna relative to one another, a directional vector can be determined since closer antennas will have earlier information than antennas that are further away.
- timing signals that are employed by the RL are generated by a time control circuit as illustrated in FIG. IA.
- the processor is operated from a first clock signal (CLK), while the transmitter and receiver(s) are operated by a second clock signal (TCLK) and third clock signal (RCLK), respectively.
- CLK first clock signal
- TCLK second clock signal
- RCLK third clock signal
- the timing signals are used by the system to digitally synthesize transmitter and receiver carrier wave signals from a locally generated oscillator signal in the RL.
- FIG. IB illustrates an example MT that is arranged to communicate with a RL.
- the example MT may be placed in a wristband, a watch, sewn into an article of clothing, or implanted in a patient such as a with a bionic-type device.
- the MT is arranged to receive a coded transmission signal, such as previously described, from the RL with receiver RCVR4 via switch SW2 and antenna ANT4.
- a band-limiting filter e.g., BPF4
- the receiver demodulates the carrier frequency with oscillator signal ROSC2 and provides I and Q information, which is subsequently captured by a capture buffer.
- the capture buffer provides output signals in the form of data to an FFT correlator, which correlates the decoded transmission with the unique identifier (ID code).
- ID code unique identifier
- the processor is arranged to cooperate with memory similar to that previously described for the RL.
- the correlator block may include an FFT correlator and a direct-form correlator.
- the signal analyzer is arranged to evaluate the outputs from the FFT correlator and /or the direct form correlator, to determine if the received transmission sequence is identified with the specific MT. When the sequence is appropriately identified, various timing signals are adjusted such that the frequency and phase of the digitally synthesized transmitter and receiver signal(s) are precisely aligned in the MT.
- Information from the coded signals is extracted by the processor once the transmission sequence is validated. Such information can include command and control instructions for the MT such as, for example, set sleep interval to a new time lapse (e.g., 10 minutes), log receiver signal strength, log invalid received signals, log receiver frequency and phase, transmit logged data, etc.
- a reply message is transmitted from the MT to the RL such that the RL can identify, locate, and receive data from the MT.
- the reply message is generated with a reply sequence generator that is keyed from the unique identifier (ID Code), similar to the transmit sequence generator.
- a low pass filter e.g., LPF2
- TXTR2 is coupled to antenna ANT4 via switch SW2 to cause the coded reply transmission (e.g., C0M31, COM32). Since an example MT operates with limited energy, the MT is normally operated in a low power or sleep mode. The energy consumed in the sleep mode is sufficient to operate a sleep timer. According to a pre-determined time interval, the MT is activated (e.g., wakeup is asserted by the sleep timer) and the MT looks for a signal to receive. When no identifiable signal can be received, the MT returns to the sleep mode.
- ID Code unique identifier
- timing signals that are employed by the MT are generated by a time control circuit as illustrated in FIG. IB.
- the processor is operated from one clock signal (CLK2), while the transmitter and receiver in the MT are operated by other clock signals (TCLK2 and RCLK2).
- CLK2 clock signal
- TCLK2 and RCLK2 other clock signals
- the various timing signals are used by the system to digitally synthesize transmitter and receiver carrier wave signals from a locally generated oscillator signal in the MT.
- the above described remote locator (RL) can be arranged to provide a relatively high power transmission signal (e.g., 1 Watt) over a long time interval (e.g., 2.5 seconds) to ensure that the MT has sufficient time to capture the necessary signals when it is active.
- the upper limit for energy that can be captured by the MT is determined by the radiated power from the RL multiplied times the capture time interval for the MT, multiplied times any loss factor due to the transmission path.
- An example transponder (MT) may be arranged to capture the signal from the RL for 157 ⁇ s, where the upper limit (ignoring path loss) for captured energy over the 157 ⁇ s time interval is approximately 157 ⁇ Jules.
- the MT can be arranged to transmit a very low power transmission signal (e.g., 10m W) for a shorter time interval (e.g., 15.7ms) than that for the RL (e.g., 2.5s).
- the upper limit for energy that can be captured by the RL is determined by the radiated power from the MT multiplied times the capture time interval for the RL, multiplied times any loss factor due to the transmission path. For a 1OmW transmission over a 15.7milli-second interval, the transmitted energy from the MT is approximately 157 ⁇ Jules.
- the RL must be carefully arranged to capture signals form the MT such as by using an integration method as will be described later. It is contemplated that in one example embodiment, the MT will be implanted in a patient, and operated over at least several years using a watch-type battery.
- the transponder is arranged to synthesize its own internal frequency for transmitting an acknowledgement signal by using the timing information that it acquires from the RL.
- the timing information that is received from the RL by the MT is Doppler shifted relative to the original transmission frequencies from the RL.
- the resulting synthesized frequency of the MT while extremely accurate, corresponds to a Doppler shifted version of the original transmission frequencies form the RL.
- the acknowledgment signal from the MT is received by the RL, but is again Doppler shifted relative to the transmitting frequencies from the MT.
- the Doppler shift that result from the round trip of the signal transmissions (i.e., transmission from the RL to the MT, and reply transmission from the MT to the RL) is hereinafter referred to as the synthetic round-trip Doppler Shift.
- FIG. 2 illustrates an example transmitter system.
- the transmitter system includes a crystal oscillator (XTAL OSC), a timing control circuit, a complex modulator, a pattern generator, an interpolation filter with timing control, integrators, and a complex cordic rotator.
- the crystal oscillator is arranged to provide an oscillator signal as a clock signal (CLOCK) having a first phase ( ⁇ for the timing control circuit.
- the crystal oscillator has a nominal frequency around 26.14 MHz, which can optionally be adjustable (e.g., via signal FREQ. TRIM).
- the oscillator can be a crystal-type oscillator, or any other oscillator that has a substantially stable oscillation frequency.
- the timing control circuit includes a feedback control loop with an optional divider circuit that is arranged to synthesize a frequency.
- the control loop includes a phase detector, a low pass filter (LPF), a voltage controlled oscillator (VCO), and an optional divider circuit.
- LPF low pass filter
- VCO voltage controlled oscillator
- phase ( ⁇ i) of the reference clock signal (e.g., CLOCK REF ) is compared to a phase ( ⁇ 2 ) from a feedback signal (e.g., CLOCK') by the phase detector to determine if the resulting clocks signal (CLOCK) is operating in phase with the reference clock (CLOCK REF )-
- the output of the phase detector corresponds to a phase difference signal (CP DIFF ) > which is provided to the low pass filter to generate a control voltage (VTUNE) for the VCO.
- CP DIFF phase difference signal
- VTUNE control voltage
- VCO adjusts the output frequency of clock signals CLKP and CLKN, which are out of phase with one another by 180 degrees.
- the feedback signal (CLOCK) is also provided from the VCO to the optional divider circuit.
- the output of the divider circuit is provided to the phase detector as signal CLOCK', which closes the control loop.
- the VCO frequency can optionally be provided to another divider circuit, which generates synthesized frequencies that are associated with a sine and cosine function.
- the VCO has a nominal output frequency of 1.83GHz
- the feedback loop divider circuit has a divide ratio of 70
- the phase detector is arranged to adjust the VTUNE signal via the low pass filter such that the average value of the 26.14MHz signal is matched to 1.83GHz/70.
- Other reference signals can be employed to yield the same result by adjusting the divider ratio in the control loop divider circuit.
- the output of the VCO can be further adjusted by the output divider circuit (e.g., divide ratio of 2) to yield synthesized frequencies corresponding to SIN(915MHz) and COS(915MHZ) or any other desired frequency.
- the pattern generator includes a code control block and a pseudo-noise generator block.
- the code control block is arranged to provide the pre-determined patterns, keyed from an ID Code, for "A", "B", and "C” sequenced patterns as will be described later.
- the pseudo-noise generator generates complex numbers (e.g., I and Q) from the codes based on the timing signals (pattern timing) for sequencing the pattern. In one example, the pseudo noise generator block is arranged to provide 2047 complex numbers.
- the complex sequence (I and Q) is provided to an interpolation filter and timing control block, which is arranged to adjust the fine timing associated with the I and Q signals, and provides F and Q', which are associated with a complex interpolated baseband signal.
- An integrator circuit is used to integrate the difference between the transmitted and received frequencies to adjust the fine timing (fine timing adjust).
- the interpolator provides fine timing adjustment for the I and Q complex numbers (e.g., 4096/2047).
- the integrator circuit can be initialized by an initialization parameter such as fm ⁇ and/or ⁇ m ⁇ -
- the interpolated complex baseband signals (F and Q') are provided to the cordic rotator.
- the cordic rotator adjusts the rotational phase of the complex baseband signals (in the digital domain) in response to a phase adjustment signal (e.g., rotation phase).
- the phase adjustment signal is provided by another integrator that integrates the frequency offset.
- the integrator circuit can again be initialized by an initialization parameter such as fi N i T and/or Cp 1N iT-
- the output of the complex cordic rotator is a frequency shifted complex baseband signal (F' and Q"), where the frequency shifting is undertaken by the digital synthesis operations by the interpolation filter and the cordic rotator.
- the complex modulator is arranged to receive the frequency shifted complex baseband signals (I" and Q"), and the sine and cosine timing signals to provide a modulated signal output.
- the modulated signal output can be provided to a power amplifier (not shown) that is coupled to an antenna for transmission of the modulated signal.
- the various timing control signals e.g., clock frequency, clock phase, clock offset
- the code control is based on a unique identifier (ID Code).
- ID Code a unique identifier
- the unique identifier is provided to a polynomial generator.
- the unique identifier is stored in a volatile memory.
- the unique identifier is stored in a non-volatile storage such as a flash memory device, a ROM, an EPROM, an EEPROM, a dip-switch, or some other means.
- the pattern that was created with the ID code is stored in a memory device or a look-up table instead of the unique identifier.
- FIG. 3 is a diagram illustrating a set of frames formatted for transmission.
- a frame corresponds to a time-period for which a sequence is transmitted.
- transmissions are broken into three sequential frames.
- a first frame i.e., "frame 1”
- Sequence A consists of a repeated set of patterns that are in a sequential series, where each pattern (pattern A) is substantially identical.
- a second frame i.e., "frame 2" is transmitted that consists of a second transmission sequence (i.e., "sequence B").
- Sequence B consists of a repeated set of patterns that are in a sequential series, where each subsequent pattern in the sequence is shifted as will be described later.
- a third frame i.e., "frame 3”
- Sequence C consists of a repeated set of patterns, where each pattern (pattern "C") forms part of an encoded message as will be described later.
- Each MT in the system has a unique identifier (e.g., an M-bit address) that is used to uniquely designate a specific MT.
- the unique identifier is a 33 -bit address code that yields approximately 8.58 billion unique identifiers.
- the M-bit address can be dispersed over the various patterns.
- a 33bit code is evenly dispersed over the three sequences such that 11-bits are coded in "sequence A", 11-bits are coded in "sequence B", and 11-bits are coded in "sequence C”.
- the codes are not evenly dispersed over the transmission sequence.
- the same code is used for each of the patterns.
- the correlation of sequence "A” is used to verify that the first portion (e.g., the first 11-bits or bits 0-10) of the unique identifier is coded in the transmission.
- the first portion e.g., the first 11-bits or bits 0-10) of the unique identifier is coded in the transmission.
- fine baud and carrier timing can be derived.
- the MT has no prior timing information (e.g., no gross frame timing is known). Since the "A" pattern is repeated over the first-time interval, it is possible to accumulate the signals by adding them on top of one another before correlation is performed such that signal sensitivity is improved. In one example MT, the accumulation of signals is unnecessary. In another example MT, the accumulation of signals is performed during a repetitive tracking mode.
- sequence "B” is used to verify that the second portion (e.g., e.g., the second 11-bits or bits 11-21) of the unique identifier is coded in the transmission.
- the "B" sequence is shifted over time. For example, a first B sequence includes coded bits BO, Bl, ... , BM, while the second B sequence (B') includes coded bits Bl, B2,...,BM, BO.
- Frame "C” has a third portion of the unique identifier encoded therein, and possible command and control data for the MT (or other data for the RL).
- the correlation of sequence "C” is used to verify the third portion (e.g., the third 11-bits or bits 22-33) of the unique identifier is coded in the transmission.
- the "C" sequence can also be very slowly modulated with a few bits of data.
- ECC error correction code
- data is encoded using an inverting and non-inverting encoding method.
- Other data encoding methods can be used such as encoding the data with a shifting bit pattern similar to the "B" sequence.
- a "000" binary code can be encoded, and each increment in the binary code is the same pattern shifted by an incremental shift step (e.g., 1 A bit step, 1 bit step, 2 bit step, etc.).
- the data message nominally in "C” can be encoded with a pattern timing changes as in the nominal section "B" previously described.
- the MT transmits sequences A and B in substantially the same format as that described above.
- Frame "C” is similarly formatted, but may include other reported data such as: current temperature, heart rate, blood pressure, etc.
- the timing and carrier signals for transmission in the MT are derived from the RL's clock as measured against the internal MT clock.
- the RL in turn correlates these signals, similar to the MT, and determines the exact round-trip time.
- the RL also determines deviations in the signal timing with respect to its own clock, which the MT attempted to mimic. The deviation in the signal timing is a consequence of Doppler shift, noise, and oscillator instability.
- An example system has the following general information:
- Frame consists of 4096 samples, 2047 baud; Sample Rate is 25. HIM complex samples/sec;
- Frame Period is 158.98 ⁇ s.
- An example system has the following RL TX parameters:
- a sequence is 2.2263 seconds long, (13x1024 frames), repeated un-shifted with one of 2047 first address portions;
- B sequence is 317.96 ms long (2000 frames), repeated shifted with one of 2047 second address portions; and "C” sequence is 19.174 ms long (64 frames), repeated un-shifted with one of
- An example system has the following MT TX parameters: "A" sequence is 81.397 ms long, (512 frames); “B” sequence is 20.349 ms long (128 frames); and
- C sequence is 10.174 ms long (64 frames), repeated un-shifted with one of 2047 third address portions, frames inverted according to modulated data.
- FIGS. 4A and 4B are diagrams illustrating the timing acquisition for an example communication system.
- the described timing acquisition sequence may be employed by the MT when receiving the three-part transmission sequence described previously with respect to FIGS. IA, IB, 2 and 3. However, as described herein, the timing acquisition sequence can be accomplished with only two of the three portions of the transmission sequence (e.g., sequence A and sequence B).
- the receiver frequency is digitally synthesized from a locally generated clock circuit (e.g., a crystal oscillator).
- the carrier wave from the RL is also digitally synthesized from its own locally generated clocking circuits, and will likely be mismatched from the receiver frequency in the MT.
- the mismatch may be related to thermal differences in the operating environment, heat transients in the circuits, crystal tolerances, processing differences between the MT and the RL, as well as other non-ideal effects.
- the overall system is not synchronized so there is no way to initially know the starting phase, frequency and cadence associated with the transmissions.
- FIG. 4A illustrates examples of phase and frequency determinations associated with an example "pattern A" sequence
- FIG. 4B illustrates the uncertainty in the receiver frequency over time during the timing acquisition.
- f initial frequency
- the MT is arranged to measure the phase associated with the received signals from pattern A as phase Cp 1 .
- the phase measurement (e.g., cpi) can be generated by an output of the correlator.
- the elapsed time for the first two measurements should be short enough to result in an expected relative phase difference of substantially less than 180 degrees to ensure that unresolveable ambiguities do not, occur. Notice that the expected phase for this time corresponds to Cp 1 .
- f Offset2 [ ⁇ 3 - ⁇ e ⁇ 3] / [360 (t 3 - 1 2 )], where ⁇ ex3 corresponds to the expected phase at time t 3 .
- the elapsed time for the first two measurements should again result in an expected relative phase difference of substantially less than 180 degrees to ensure that unresolveable ambiguities do not occur.
- the absolute phase difference is expected to be significantly larger than 360 degrees such that the time difference between successive offset calculations can be gradually spaced further and further apart as the timing acquisition is adjusted by each subsequent estimate. Notice that the frequency error is gradually reduced with each subsequent adjustment until limited by the Allan Variance.
- FIG. 4B is a graph illustrating the uncertainty in the digitally synthesized receiver frequency over an elapsed timing acquisition period. Note that the scale for both axes is logarithmic, and that the uncertainty will asymptotically approach the Allan Variance associated with the local oscillator circuits in the MT (or the RL as the case may be).
- the horizontal axis illustrates elapsed time, while the vertical axis illustrates the uncertainty in the frequency.
- Each successive time period has a refined estimate of the receiver timing such that the uncertainty decreases in an exponential fashion.
- a knee in the uncertainty curve occurs after sufficient samples of the received signal are acquired (e.g., at time t 5 ) such that estimates for the received carrier wave frequency asymptotically approach a minimum uncertainty that is determined by the Allan variance.
- FIG. 5 A is a block diagram for an example receiver.
- the example receiver includes an antenna (ANT), an optional filter, a low noise amplifier (LNA), a first mixer, a second mixer, a first low pass filter (LPFl), a second low pass filter (LPF2), an analog-to- digital converter (ADC), a buffer, an FFT processor, a correlator, and an inverse FFT processor.
- ANT antenna
- LNA low noise amplifier
- LPFl low pass filter
- LPF2 low pass filter
- ADC analog-to- digital converter
- the antenna is arranged to couple received signals to the LNA through the optional filter (e.g., a band-pass filter).
- the LNA is arranged to increase signal strength, and couple the increased signal to the mixers.
- the first mixer is arranged to generate an in-phase signal (I) with a cosine wave heterodyne, while the second mixer is arranged to generate quadrature signal (Q) with a sine wave heterodyne.
- the in-phase signal is coupled to the ADC via LPFl as signal I A
- the quadrature-phase signal is coupled to the ADC via LPF2 as signal Q A .
- the ADC is operated at a sampling frequency (fsAivr)-
- the ADC can be implemented as a single AfD converter circuit with time division multiplexing between the I A and Q A signals.
- the ADC can alternatively be implemented as two separate AfD converter circuits.
- the ADC circuits convert the I A and Q A signals to quantized digital signals that are coupled to the buffer as signals I D and Q D , respectively.
- the buffer can be implemented as one contiguous memory, as partitioned memory (e.g., MEMl, MEM2, etc.), or any other appropriate temporary storage that buffers the captured data.
- the output of the buffer is coupled to the FFT processor, which converts the input signal to the frequency domain.
- the FFT of the reference signal is complex conjugate multiplied with the frequency domain representation of the captured signal.
- An inverse FFT of the product is taken, which is the circular correlation of the captured signal and the selected reference signal. Since the FFT reference is determined from the unique identifier of a MT (e.g., ID Code), the correlation of the FFT processor output will peak when a valid received code is identified in the signal.
- the carrier phase and pattern timing are also extracted from the received signals.
- FIG. 5B illustrates operations in a receiver that may be performed as a DSP block.
- the FFT reference signal is provided as an array of N-bins.
- the captured signal is calculated as an FFT, also of N bins.
- the complex conjugate of each complex element in a designated storage bin (BIN 1 - BIN N) is multiplied by the data from the other corresponding storage bin.
- the complex conjugate of the FFT reference signal is stored in a first array (ARRAY 1) as D RI - D RN
- the FFT capture data is stored in a second array (ARRAY 2) as Dei - D CN -
- the FFT reference signal is stored in the first array (ARRAY 1) as D R1 - D RN
- the complex conjugate of the FFT capture data is stored in the second array (ARRAY 2) as Dei - D CN -
- the multipliers are arranged to receive data from the first array and the second array to provide a multiplied output, yielding a product result that can be stored in a third array (ARRAY 3) as D MI - D MN -
- An inverse FFT is computed from the product identified in the third array (ARRAY 3), to retrieve the circular correlator output.
- the circular correlator output results can be stored in a fourth array (ARRAY 4), or can optionally overwrite the values from the third array (ARRAY 3).
- the contents of the fourth array (ARRAY 4), or the third array depending on the implementation, are a complex result that includes both magnitudes and phases. As illustrated in FIG.
- the inverse FFT of the circular correlator output has a peak magnitude (PEAK) that occurs when the FFT reference ad the captured data correlate with one another.
- PEAK peak magnitude
- FIG. 6 is a flow chart for an example transmitter in either a MT or a receiver. Processing begins when a user, or some other process, initiates a request to locate a particular MT.
- a transmission sequence is initialized with a unique identifier (ID Code). Sequences are generated for frame transmission such as sequence “A”, “B”, and “C” as previously described. Each of the "A”, “B”, and “C” sequences are encoded with a portion of the unique code.
- ID Code unique identifier
- the RL begins transmitting pattern "A", and repeats transmitting pattern "A” (Note: un-shifted) until the entire "A" sequence is completed (e.g., 13x1024 sequential patterns, or frame “A”).
- the RL then begins transmitting pattern "B".
- the pattern is shifted such as using a bit rotation algorithm, as previously described.
- the RL begins transmitting the "C” pattern.
- the sequence of "C” patterns includes modulated data that may correspond to command and control information for the MT. After the modulated data is transmitted (e.g., 64 sequential pattern, or frame "C”), the RL stops transmitting and switches into a receive mode.
- signals are received from the MT with the RL in a similar format as provided between the RL and the MT.
- the RL can then calculate a distance and location based on the round-trip time and Doppler shift in the received signals as previously described.
- the received "C" frame transmission may include data that is communicated between the MT and the RL, which is extracted and evaluated by the RL.
- Such data may include: physiological information such as heart rate, body temperature, blood pressure, heart rhythm, blood-sugar level, as well as other sensory information that is associated with a user of the MT.
- FIGS. 7A is an example flow chart for an example receiver in a MT. Processing begins when the MT is activated out of a sleep mode (e.g., WAKE-UP is initiated).
- FIG. 7A illustrates the capture of samples associated with sequence "A" (or frame "A"). After wake-up is initiated, the receiver captures noise and/or signals.
- the MT will attempt to correlate the captured noise and/or signals with the first portion of the unique identifier for the specific MT. When the correlation fails to match, the MT determines that the transmission is intended for another device, or possibly that no transmission is present, and returns to a sleep mode. Alternatively, the MT extracts baud and carrier timing info ⁇ nation from the transmission sequence to refine the receiver timings.
- Timing is refined by repeatedly scheduling capture intervals.
- the receiver waits, and then begins capturing a portion of the samples from each scheduled capture time, and attempts to correlate the captured samples with another portion of the reference that is keyed to the code for the MT.
- the timing for the receiver is adjusted (bootstrapped) to further refine the time/frequency estimates.
- the correlation of pattern A fails to match the coded reference and processing continues to capture and evaluate pattern B as will be described with respect to FIG. 8A.
- FIG. 7B illustrates the capture of samples associated with sequence "A" (or frame "A") in a receiver of a RL device. Since the MT has limited power available for transmission, the signal may be considerably weaker than that from the RL. After wake-up is initiated by the RL, the receiver captures noise and/or signals. The RL will continue to capture the transmission for a predetermined time interval and accumulate values using a cyclic accumulation capture technique (e.g., an array of capture buffers that are cyclically selected in sequence). For each subsequent capture, the selected capture buffer is changed based on the time. Also, an accelerometer is used to measure the speed of the RL device for estimating time for reception, etc.
- a cyclic accumulation capture technique e.g., an array of capture buffers that are cyclically selected in sequence.
- an accelerometer is used to measure the speed of the RL device for estimating time for reception, etc.
- the RL attempts to FFT correlate the accumulated/captured signals and noise with the first portion of the unique identifier for the specific RL.
- the accumulation of the captured patterns over the sequence using the described cyclic accumulation improves the signal levels and minimizes the impact of noise on the reception.
- the RL determines that the transmission is intended for another device, that no transmission is present, or that an error has occurred, and returns to a sleep mode.
- the RL fine timing and phase information from the transmission sequence is used to refine the receiver timings for the RL. Processing then continues to capture and evaluate pattern B as will be described with respect to FIG. 8B.
- FIG. 8A illustrates the capture of samples associated with pattern "B" in a MT device.
- the receiver captures a sequence of samples, assuming those samples correspond to sequence "B".
- the MT will attempt to FFT correlate the captured samples with the second portion of the unique identifier for the specific MT. When the correlation fails to identify a match, the MT may determine that the signal sequence is intended for another device. During a processing time interval, the expected B sequence is shifted and captured, and FFT correlation determinations then follow. When the processing time interval completes without a match of sequence "B", the MT determines that the transmission is intended for another MT or that there is no transmission to receive and returns to a sleep mode.
- the MT determines the relative position of the matched pattern within the sequence (or within the frame) based on the shift position that yields a match. Since the timing, phase, and frequency information are now known, the MT schedules reception of the "C" sequence. Processing continues for the MT in FIG. 9, which follows further below.
- FIG. 8B illustrates the capture of samples associated with pattern "B" in a RL device.
- the receiver captures a sequence of samples, assuming those samples correspond to sequence "B" using a cyclic accumulation/integration technique that is similar to that previously described for FIG. 7B.
- a reference pattern associated with pattern "B: is generated.
- Each received sample from a portion of a capture sequence is captured and placed in a respective one of a series of buffers, where each buffer has an associated index such as a pointer.
- each subsequent captured sample is placed in a different capture buffer (e.g., a capacitive storage cell).
- the RL will attempt to FFT correlate the integrated captured sequence with the previously generated pattern for pattern "B". When the FFT correlation fails to identify a match, the RL falls into an error trap. Processing a received sequence may expire without match when the transmission is intended for another MT, or perhaps when an error has occurred. An error trap handles the remaining processing when an error occurs.
- the reference pattern for "sequence B” must be rotated using a cyclic rotating process as previously described so that the reference pattern is aligned with the transmitted cyclically rotated pattern.
- the described rotated pattern is illustrated and described as Pattern "B'" with respect to FIG. 3.
- the RL finds a circular correlation match for the generated pattern "B” (or any subsequently rotated version thereof)
- the RL can then determine the relative position of the matched pattern within the sequence (or within the frame) based on the circularly rotated (e.g., shifted) pattern that yields a match. Since the timing, phase, and frequency information are now known, the RL schedules to receive the "C" sequence. Processing continues for the RL in FIG. 9, which follows below.
- FIG. 9 which follows below.
- FIG 9 illustrates the capture of samples associated with sequence "C".
- the receiver captures samples from the receiver in the MT, assuming those symbols correspond to pattern "C”.
- the MT will continue to capture samples until the frame is expected to reach completion.
- the MT will then attempt to correlate the captured sequence (assuming it is sequence "C" from the RL) with the third portion of the unique identifier for the specific MT.
- Sequence "C” includes data modulated therein that may be coded with error correcting codes (ECC), where the coded information can be phase modulated and subsequently demodulated and decoded.
- ECC error correcting codes
- the MT determines that the transmission is intended for another and traps an error condition appropriately.
- the MT finds a match for pattern "C” and evaluates the polarities of the symbols received in this frame, and extracts command and control information from the "C" sequence.
- sequences "A”, “B”, and “C2" or some other order, perhaps, or even a different set of A'B'C.
- Sequences "A” and “B” include a similar pattern as previously described for the RL, although shorter in length.
- Sequence “C2" is still the same number of frames except that data is encoded into the transmission for communication between the MT and the RL.
- sequence C is followed by evaluation of the round-trip time to determine linear distance from the RL to the MT.
- a time difference is evaluated between the reception of two signals that are received from two different receiving antennas to help identify a vector for direction between the RL and the MT.
- An analysis of a Doppler shift in the received signals from the MT can also be used to assist in the determination of the directional vector.
- sequence "C" is evaluated to extract transferred information from the MT to the RL.
- An accelerometer is included in the RL to assist in identification of the location based on the speed associated with the RL. Once the round-trip time and the Doppler shift are known, the information can be combined with the speed and heading of the RL to identify a direction and distance from the RL to the MT.
- the present disclosure merges "location request" polling with the location process itself.
- the RL device is arranged to provide a relatively lengthy, powerful, coded signal whose duration spans the polling interval of the MT.
- the MT very briefly samples the relevant spectrum, and finds a coded spread spectrum signal.
- the MT perfo ⁇ ns multiple signal captures from the lengthy transmission, making successively more accurate estimates of the signals frequency, cadence, and time reference. These estimates are limited in precision by the short-term stability (root Allan variance) of the MT's time base (e.g., a quartz crystal oscillator) and by the relative acceleration between the RL and the MT.
- the MT can use the precise estimate of the received signal timing to synthesize a coded spread spectrum reply with substantially the same timing and carrier frequency.
- This reply signal is emitted shortly after the end of the incoming signal. Since the timing is accurately captured, the presence of a delay or gap doesn't materially degrade accuracy. For example, if the time-base error is 2ppb, then a 30 ms delay translates into a time uncertainty of approximately 60 ps, which is about one centimeter of round trip distance.
- the coded reply signal from the MT is sufficiently lengthy so that integration over time compensates for its relatively low power.
- the signal from the MT can be coherently processed by the RL since the return signal is coherent plus or minus the synthetic round-trip Doppler shift with the RL' s time base.
- a cyclic set of 4096 complex capacitive integrators can be used to perform the process of signal accumulation to raise the weak signals up and out of the noise floor.
- the complex patterns (e.g., a pattern of length 2047 chips) have approximately 33db of spreading gain.
- the addition of the cyclic integrators can achieve an additional 20db of signal gain with the repetitive portions of the signal, yielding 53 db of total gain. A bandwidth reduction from 26MHz down to about 100Hz is achieved with this technique.
- the thermal noise over the lOOHz bandwidth is approximately -154dbm, where reasonable signal reception is expected around a noise level of -140dbm.
- a maximum path loss of 15OdB is achieved for a +10dbm transmitter.
- the corresponding ideal free space range for this transmitter is approximately 1000 km assuming a 915 MHz signal and omnidirectional antennae. This large free space range or loss margin is useful for building penetration, implanted devices, and so forth.
- the capture duration in the MT is limited by the relative crystal frequency tolerance between the MT and the RL. With time and temperature, and taking advantage of periodic calibration signals, this tolerance can be managed to a few parts per million. Thus, the product of the signaling frequency and the crystal tolerance gives a frequency offset, which in turn indicates the maximum possible reception time without the use of multiple Doppler bins or repeated correlation attempts. For example at 915 MHz and with a 3.5ppm frequency error, a capture period of 312 ⁇ s would correspond to a first complete signal null.
- the RL will in general receive a signal whose cadence and frequency very closely match its internal crystal clock, and thus the RL can use long cyclic integration times, which greatly increase the available signal to noise ratio.
- the described coherent integration (or coherent accumulation) process has a signal power maximum when the signal has rotated through 180 degrees at the end of the capture interval. For a 3.5ppm frequency tolerance, when the period of the spread signal is designed to be about 150 ⁇ s. It is advantageous to use a signal which is itself complex. Improved orthogonality between coded signals is achieved by using a complex signal.
- the Gold codes used in the GPS system have a length of 1023 chips with a cross correlation of approximately -24db for 1025 possible codes.
- the complex signaling codes employed in the presently described disclosure is on the order of length 2047 chips, with a cross-correlation of -33db for 2048 possible codes. The use of complex codes allows for improved signal rejection.
- the round trip Doppler shift between slowly moving objects is on the order of 4 - 5 ppb.
- Slowly moving objects provide a significantly longer integration time in cases where the received signal is likely to be very close in frequency to the RL's time base. Even automobile speeds will result in a round-trip Doppler-shift of 200 ppb or less.
- the described system performs distance measurement by round trip time measurement.
- the system also determines bearing between the RL and the MT by determining the associated Doppler-shift in the return signal.
- a Doppler shift is measured when the RL velocity is known (e.g., moving in a vehicle at a fixed rate).
- a differential Doppler shift is measured when the acceleration of the RL is known, allowing for target location even with moving targets using positional vector analysis.
- the RL' s acceleration vector is readily measured with at least one of: a three-axis accelerometer, a GPS set with a clear view of the sky, or any other appropriate means.
- the position fixes may have a two-fold ambiguity in location, since for linear motion two angle estimates exist.
- the position fix is resolved in one example, by utilizing two antennas. Since the closer antenna will receive the return signal before the distant antenna, ambiguity for nonlinear motion can be resolved by determining "which antenna is closer".
- the presently described system, apparatus, and methods take advantage of the acquired frequency knowledge to allow for synthesis of a time and phase coherent response to accurately determine location with a low-power MT.
Landscapes
- Engineering & Computer Science (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Mobile Radio Communication Systems (AREA)
- Radar Systems Or Details Thereof (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US13/348,507 USRE45061E1 (en) | 2005-03-14 | 2005-12-20 | System and method for locating objects and communicating with the same |
AU2005329042A AU2005329042B2 (en) | 2005-03-14 | 2005-12-20 | System and method for locating objects and communicating with the same |
CA2600708A CA2600708C (en) | 2005-03-14 | 2005-12-20 | System and method for locating objects and communicating with the same |
EP05854967.6A EP1869728B1 (en) | 2005-03-14 | 2005-12-20 | System and method for locating objects and communicating with the same |
US11/885,843 US7646330B2 (en) | 2005-03-14 | 2005-12-20 | System and method for locating objects and communicating with the same |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US66177105P | 2005-03-14 | 2005-03-14 | |
US60/661,771 | 2005-03-14 | ||
US73059205P | 2005-10-26 | 2005-10-26 | |
US60/730,592 | 2005-10-26 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2006098791A2 true WO2006098791A2 (en) | 2006-09-21 |
WO2006098791A3 WO2006098791A3 (en) | 2009-04-09 |
Family
ID=36992172
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2005/046333 WO2006098791A2 (en) | 2005-03-14 | 2005-12-20 | System and method for locating objects and communicating with the same |
Country Status (5)
Country | Link |
---|---|
US (2) | USRE45061E1 (en) |
EP (1) | EP1869728B1 (en) |
AU (1) | AU2005329042B2 (en) |
CA (1) | CA2600708C (en) |
WO (1) | WO2006098791A2 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102077613A (en) * | 2008-04-25 | 2011-05-25 | 爱立信电话股份有限公司 | Radio fingerprint method in a positioning node for providing geographic region data |
CN102193081A (en) * | 2010-03-17 | 2011-09-21 | 斯沃奇集团研究及开发有限公司 | Method and system for locating objects |
US9883815B2 (en) | 2015-04-20 | 2018-02-06 | Össur Iceland Ehf | Electromyography with prosthetic or orthotic devices |
Families Citing this family (78)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP2333583A1 (en) * | 2006-03-06 | 2011-06-15 | Qualcomm Incorporated | Method for position determination with measurement stitching |
US20070213085A1 (en) * | 2006-03-13 | 2007-09-13 | Honeywell International Inc. | Method and system to correct for Doppler shift in moving nodes of a wireless network |
US9489813B1 (en) * | 2006-09-22 | 2016-11-08 | Michael L. Beigel | System for location in environment and identification tag |
US7917155B2 (en) | 2006-10-27 | 2011-03-29 | Roundtrip Llc | Location of cooperative tags with personal electronic device |
US8994533B2 (en) * | 2006-11-30 | 2015-03-31 | Patent Navigation, Inc. | Conditional RFID |
EP2065726B9 (en) * | 2007-11-13 | 2012-04-25 | Universitetet I Oslo | Ultrasound zone location system with high capacity |
CN101587628A (en) * | 2008-05-21 | 2009-11-25 | 深圳富泰宏精密工业有限公司 | Alarm monitoring system and method for handheld mobile electronic device |
US8744481B2 (en) * | 2008-06-24 | 2014-06-03 | Telefonaktiebolaget L M Ericsson (Publ) | Method for providing geographical position related information in a wireless network |
MX2011001118A (en) * | 2008-07-30 | 2011-05-23 | Bitcarrier S L | System and method for monitoring people and/or vehicles in urban environments. |
US9074897B2 (en) * | 2009-06-15 | 2015-07-07 | Qualcomm Incorporated | Real-time data with post-processing |
JP5339150B2 (en) * | 2009-09-30 | 2013-11-13 | ソニー株式会社 | Wireless communication device |
US8823577B2 (en) * | 2009-12-23 | 2014-09-02 | Itrack, Llc | Distance separation tracking system |
IT1397141B1 (en) * | 2009-12-28 | 2013-01-04 | Cover Technology S R L | RADAR 3D DEVICE. |
US8749433B2 (en) * | 2010-04-02 | 2014-06-10 | Position Imaging, Inc. | Multiplexing receiver system |
FR2959318B1 (en) * | 2010-04-22 | 2013-04-05 | Eurocopter France | CONTINUOUS LOCATION OF GREAT PRECISION |
US8441391B2 (en) | 2010-05-05 | 2013-05-14 | Roundtrip Llc | Ultra-secure communication methods and apparatus |
US8704707B2 (en) | 2010-06-02 | 2014-04-22 | Qualcomm Incorporated | Position determination using measurements from past and present epochs |
EP2407799B1 (en) * | 2010-07-16 | 2018-04-11 | Sivers Ima AB | Method and device for continuous wave radar measurements |
NZ608950A (en) * | 2010-10-19 | 2014-08-29 | Renewable Energy Systems Americas Inc | Systems and methods for avian mitigation for wind farms |
US11175375B2 (en) | 2010-11-12 | 2021-11-16 | Position Imaging, Inc. | Position tracking system and method using radio signals and inertial sensing |
US8957812B1 (en) | 2010-11-12 | 2015-02-17 | Position Imaging, Inc. | Position tracking system and method using radio signals and inertial sensing |
US10416276B2 (en) | 2010-11-12 | 2019-09-17 | Position Imaging, Inc. | Position tracking system and method using radio signals and inertial sensing |
US8384584B2 (en) | 2010-12-10 | 2013-02-26 | Roundtrip Llc | Reduced computation communication techniques for location systems |
GB2489002A (en) * | 2011-03-14 | 2012-09-19 | Nujira Ltd | Delay adjustment to reduce distortion in an envelope tracking transmitter |
US9041598B2 (en) * | 2011-06-22 | 2015-05-26 | Raytheon Company | Non Doppler-tolerant pulse compression in radar systems |
US9945940B2 (en) | 2011-11-10 | 2018-04-17 | Position Imaging, Inc. | Systems and methods of wireless position tracking |
US9933509B2 (en) | 2011-11-10 | 2018-04-03 | Position Imaging, Inc. | System for tracking an object using pulsed frequency hopping |
US9782669B1 (en) | 2012-06-14 | 2017-10-10 | Position Imaging, Inc. | RF tracking with active sensory feedback |
US10269182B2 (en) | 2012-06-14 | 2019-04-23 | Position Imaging, Inc. | RF tracking with active sensory feedback |
US9092678B2 (en) | 2012-07-31 | 2015-07-28 | Lawrence J. Karr | Systems and methods to locate an object |
US9519344B1 (en) | 2012-08-14 | 2016-12-13 | Position Imaging, Inc. | User input system for immersive interaction |
US10180490B1 (en) | 2012-08-24 | 2019-01-15 | Position Imaging, Inc. | Radio frequency communication system |
US10234539B2 (en) | 2012-12-15 | 2019-03-19 | Position Imaging, Inc. | Cycling reference multiplexing receiver system |
US10856108B2 (en) | 2013-01-18 | 2020-12-01 | Position Imaging, Inc. | System and method of locating a radio frequency (RF) tracking device using a calibration routine |
US9482741B1 (en) | 2013-01-18 | 2016-11-01 | Position Imaging, Inc. | System and method of locating a radio frequency (RF) tracking device using a calibration routine |
US9622324B2 (en) | 2013-11-21 | 2017-04-11 | General Electric Company | Geolocation aid and system |
US10509101B2 (en) | 2013-11-21 | 2019-12-17 | General Electric Company | Street lighting communications, control, and special services |
US9420674B2 (en) | 2013-11-21 | 2016-08-16 | General Electric Company | System and method for monitoring street lighting luminaires |
US9621265B2 (en) | 2013-11-21 | 2017-04-11 | General Electric Company | Street lighting control, monitoring, and data transportation system and method |
US9646495B2 (en) | 2013-11-21 | 2017-05-09 | General Electric Company | Method and system for traffic flow reporting, forecasting, and planning |
US12000947B2 (en) | 2013-12-13 | 2024-06-04 | Position Imaging, Inc. | Tracking system with mobile reader |
US10634761B2 (en) | 2013-12-13 | 2020-04-28 | Position Imaging, Inc. | Tracking system with mobile reader |
US9606224B2 (en) * | 2014-01-14 | 2017-03-28 | Alstom Transport Technologies | Systems and methods for vehicle position detection |
US9497728B2 (en) | 2014-01-17 | 2016-11-15 | Position Imaging, Inc. | Wireless relay station for radio frequency-based tracking system |
US10200819B2 (en) | 2014-02-06 | 2019-02-05 | Position Imaging, Inc. | Virtual reality and augmented reality functionality for mobile devices |
US9941926B2 (en) | 2014-03-12 | 2018-04-10 | 3Db Access Ag | Method, apparatus and computer program for determining a time of arrival |
US9995824B2 (en) * | 2014-04-09 | 2018-06-12 | Thomas Danaher Harvey | Methods and system to assist search for lost and submerged objects |
US10871566B2 (en) * | 2014-04-09 | 2020-12-22 | Thomas Danaher Harvey | Methods and system to assist search and interception of lost objects |
US9885772B1 (en) | 2014-08-26 | 2018-02-06 | Vencore Labs, Inc. | Geolocating wireless emitters |
US9826418B2 (en) * | 2014-09-22 | 2017-11-21 | Intel Corporation | Apparatus, system and method of performing a time of flight (ToF) measurement |
US10468768B2 (en) * | 2014-09-30 | 2019-11-05 | Lawrence J. Karr | Holonomically constrained (tethered) spin-around locator |
US12079006B2 (en) | 2015-02-13 | 2024-09-03 | Position Imaging, Inc. | Spatial diversity for relative position tracking |
US11132004B2 (en) | 2015-02-13 | 2021-09-28 | Position Imaging, Inc. | Spatial diveristy for relative position tracking |
US10642560B2 (en) | 2015-02-13 | 2020-05-05 | Position Imaging, Inc. | Accurate geographic tracking of mobile devices |
US10324474B2 (en) | 2015-02-13 | 2019-06-18 | Position Imaging, Inc. | Spatial diversity for relative position tracking |
US10853757B1 (en) | 2015-04-06 | 2020-12-01 | Position Imaging, Inc. | Video for real-time confirmation in package tracking systems |
US11501244B1 (en) | 2015-04-06 | 2022-11-15 | Position Imaging, Inc. | Package tracking systems and methods |
US10148918B1 (en) | 2015-04-06 | 2018-12-04 | Position Imaging, Inc. | Modular shelving systems for package tracking |
US11416805B1 (en) | 2015-04-06 | 2022-08-16 | Position Imaging, Inc. | Light-based guidance for package tracking systems |
EP3193191B1 (en) * | 2016-01-15 | 2019-09-18 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Method and system for measuring location and/or orientation |
US10444323B2 (en) | 2016-03-08 | 2019-10-15 | Position Imaging, Inc. | Expandable, decentralized position tracking systems and methods |
US11436553B2 (en) | 2016-09-08 | 2022-09-06 | Position Imaging, Inc. | System and method of object tracking using weight confirmation |
US10634506B2 (en) | 2016-12-12 | 2020-04-28 | Position Imaging, Inc. | System and method of personalized navigation inside a business enterprise |
US10455364B2 (en) | 2016-12-12 | 2019-10-22 | Position Imaging, Inc. | System and method of personalized navigation inside a business enterprise |
US10634503B2 (en) | 2016-12-12 | 2020-04-28 | Position Imaging, Inc. | System and method of personalized navigation inside a business enterprise |
US11120392B2 (en) | 2017-01-06 | 2021-09-14 | Position Imaging, Inc. | System and method of calibrating a directional light source relative to a camera's field of view |
US10705199B2 (en) * | 2017-11-30 | 2020-07-07 | Urban Canyon Flight | Aviation transponder |
US11719807B2 (en) | 2017-12-20 | 2023-08-08 | Arizona Board Of Regents On Behalf Of Arizona State University | Phase-accurate vehicle positioning systems and devices |
US11656321B2 (en) | 2018-07-23 | 2023-05-23 | Richwave Technology Corp. | Method of microwave motion detection with adaptive frequency control and related devices |
US10868618B2 (en) * | 2018-09-13 | 2020-12-15 | Kristin Renee Little | Device and method for providing a synchronized pattern sequence on multiple devices |
US11361536B2 (en) | 2018-09-21 | 2022-06-14 | Position Imaging, Inc. | Machine-learning-assisted self-improving object-identification system and method |
WO2020146861A1 (en) | 2019-01-11 | 2020-07-16 | Position Imaging, Inc. | Computer-vision-based object tracking and guidance module |
US11172334B2 (en) | 2019-02-11 | 2021-11-09 | Arizona Board Of Regents On Behalf Of Arizona State University | Hyper-precise positioning and communications system and network |
US11988735B2 (en) * | 2019-11-04 | 2024-05-21 | Arizona Board Of Regents On Behalf Of Arizona State University | Position information estimation in a distributed radio frequency (RF) communications system |
US12050283B2 (en) | 2019-11-04 | 2024-07-30 | Arizona Board Of Regents On Behalf Of Arizona State University | Estimation and tracking of position information in a distributed radio frequency (RF) communications system |
FR3103070B1 (en) * | 2019-11-13 | 2024-03-22 | Univ Grenoble Alpes | Method for synchronizing a communication system based on data retransmission |
JP2023522540A (en) * | 2020-02-14 | 2023-05-31 | ピー-チップ・アイピー・ホールディングス・インコーポレイテッド | optical trigger transponder |
US20220086646A1 (en) | 2020-09-17 | 2022-03-17 | P-Chip Ip Holdings Inc. | Devices, systems, and methods using microtransponders |
Family Cites Families (41)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3049709A (en) * | 1957-12-27 | 1962-08-14 | Jr Lockwood Rianhard | Remote control actuated chemical-nuclear powered communication system |
US3755811A (en) * | 1968-06-10 | 1973-08-28 | Rca Corp | Discriminating signaling system |
US3568161A (en) * | 1968-09-04 | 1971-03-02 | Elwyn Raymond Knickel | Vehicle locator system |
US3646580A (en) * | 1969-07-18 | 1972-02-29 | Raytheon Co | Surface vehicle fleet command and control system |
US3662267A (en) * | 1970-05-20 | 1972-05-09 | Sylvania Electric Prod | System for locating and communicating with mobile units |
US3714650A (en) * | 1970-07-30 | 1973-01-30 | Raytheon Co | Vehicle command and control system |
US3839717A (en) * | 1972-01-28 | 1974-10-01 | Identification Co Inc | Communication apparatus for communicating between a first and a second object |
GB1605316A (en) * | 1977-02-20 | 1989-07-19 | Emi Ltd | Improvements in or relating to identification of friend or foe(iff)systems |
US4675656A (en) * | 1984-03-16 | 1987-06-23 | Narcisse Bernadine O | Out-of-range personnel monitor and alarm |
US4611198A (en) * | 1985-09-19 | 1986-09-09 | Levinson Samuel H | Security and communication system |
US4818998A (en) * | 1986-03-31 | 1989-04-04 | Lo-Jack Corporation | Method of and system and apparatus for locating and/or tracking stolen or missing vehicles and the like |
US4908629A (en) * | 1986-03-31 | 1990-03-13 | Lo-Jack Corporation | Apparatus for locating and/or tracking stolen or missing vehicles and the like |
US4952913A (en) * | 1986-04-15 | 1990-08-28 | B. I. Incorporated | Tag for use with personnel monitoring system |
US4797948A (en) * | 1987-07-22 | 1989-01-10 | Motorola, Inc. | Vehicle identification technique for vehicle monitoring system employing RF communication |
US4918425A (en) * | 1988-07-25 | 1990-04-17 | Daniel E. Ely | Monitoring and locating system for an object attached to a transponder monitored by a base station having an associated ID code |
US4897642A (en) * | 1988-10-14 | 1990-01-30 | Secura Corporation | Vehicle status monitor and management system employing satellite communication |
US5126733A (en) * | 1989-05-17 | 1992-06-30 | Motorola, Inc. | Location information polling in a communication system |
US5119104A (en) * | 1990-05-04 | 1992-06-02 | Heller Alan C | Location system adapted for use in multipath environments |
US5199044A (en) * | 1990-05-22 | 1993-03-30 | Tokimec Inc. | System for detecting position of object having data carrier |
US5278563A (en) * | 1992-09-08 | 1994-01-11 | Spiess Newton E | Vehicle identification and classification systems |
US5418537A (en) * | 1992-11-18 | 1995-05-23 | Trimble Navigation, Ltd. | Location of missing vehicles |
US5396218A (en) * | 1993-07-23 | 1995-03-07 | Olah; George | Portable security system using communicating cards |
US5493286A (en) * | 1994-03-10 | 1996-02-20 | Motorola, Inc. | Method for providing communications within a geographic region |
US5576716A (en) * | 1994-12-07 | 1996-11-19 | Sadler; Kermit M. | Owner oriented system for locating lost or stolen property |
US5798693A (en) * | 1995-06-07 | 1998-08-25 | Engellenner; Thomas J. | Electronic locating systems |
US5959568A (en) * | 1996-06-26 | 1999-09-28 | Par Goverment Systems Corporation | Measuring distance |
KR20000049066A (en) * | 1996-10-17 | 2000-07-25 | 핀포인트 코포레이션 | Article tracking system |
US6812824B1 (en) * | 1996-10-17 | 2004-11-02 | Rf Technologies, Inc. | Method and apparatus combining a tracking system and a wireless communication system |
US5920287A (en) * | 1997-01-21 | 1999-07-06 | Widata Corporation | Radio location system for precisely tracking objects by RF transceiver tags which randomly and repetitively emit wideband identification signals |
US6219596B1 (en) * | 1997-09-18 | 2001-04-17 | Mitsubishi Denki Kabushiki Kaisha | Automated highway tracking and communication system and method |
IL122079A (en) * | 1997-10-30 | 2002-02-10 | Netmor Ltd | Ultrasonic positioning and tracking system |
US6317049B1 (en) * | 1998-02-17 | 2001-11-13 | Souhail Toubia | Apparatus and method for locating missing persons, animals, and objects |
US6243025B1 (en) * | 1998-06-10 | 2001-06-05 | Honda Giken Kogyo Kabushiki Kaisha | Moving body detection system |
JP3871097B2 (en) * | 1998-06-10 | 2007-01-24 | 本田技研工業株式会社 | Moving object detection system |
ATE413609T1 (en) * | 1998-09-03 | 2008-11-15 | Wherenet Inc | MULTIPLE LATERAL NETWORK WITH CIRCULAR POLARIZED ANTENNA |
US6300902B1 (en) * | 1999-02-10 | 2001-10-09 | At&T Corp | Personalized locator method and apparatus |
US6556942B1 (en) * | 2000-09-29 | 2003-04-29 | Ut-Battelle, Llc | Short range spread-spectrum radiolocation system and method |
US7253717B2 (en) * | 2000-11-29 | 2007-08-07 | Mobile Technics Llc | Method and system for communicating with and tracking RFID transponders |
US6882315B2 (en) * | 2001-10-18 | 2005-04-19 | Multispectral Solutions, Inc. | Object location system and method |
US20050228659A1 (en) * | 2004-04-06 | 2005-10-13 | Vlad Mitlin | Stealth communication method |
GB0418376D0 (en) * | 2004-08-18 | 2004-09-22 | Loc8Tor Ltd | Locating system |
-
2005
- 2005-12-20 EP EP05854967.6A patent/EP1869728B1/en not_active Not-in-force
- 2005-12-20 WO PCT/US2005/046333 patent/WO2006098791A2/en active Application Filing
- 2005-12-20 US US13/348,507 patent/USRE45061E1/en active Active
- 2005-12-20 CA CA2600708A patent/CA2600708C/en not_active Expired - Fee Related
- 2005-12-20 US US11/885,843 patent/US7646330B2/en not_active Ceased
- 2005-12-20 AU AU2005329042A patent/AU2005329042B2/en not_active Ceased
Non-Patent Citations (1)
Title |
---|
See references of EP1869728A4 * |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102077613A (en) * | 2008-04-25 | 2011-05-25 | 爱立信电话股份有限公司 | Radio fingerprint method in a positioning node for providing geographic region data |
CN102193081A (en) * | 2010-03-17 | 2011-09-21 | 斯沃奇集团研究及开发有限公司 | Method and system for locating objects |
EP2367021A1 (en) * | 2010-03-17 | 2011-09-21 | The Swatch Group Research and Development Ltd. | Method and system for locating objects |
EP2367022A1 (en) * | 2010-03-17 | 2011-09-21 | The Swatch Group Research and Development Ltd. | Method and system for locating objects |
JP2011196998A (en) * | 2010-03-17 | 2011-10-06 | Swatch Group Research & Development Ltd | Position identification method and system for searched object |
US8624774B2 (en) | 2010-03-17 | 2014-01-07 | The Swatch Group Research And Development Ltd | Method and system of locating objects |
KR101349418B1 (en) * | 2010-03-17 | 2014-01-08 | 더 스와치 그룹 리서치 앤 디벨롭먼트 엘티디 | Method and system of locating objects |
US9883815B2 (en) | 2015-04-20 | 2018-02-06 | Össur Iceland Ehf | Electromyography with prosthetic or orthotic devices |
US11051957B2 (en) | 2015-04-20 | 2021-07-06 | Össur Iceland Ehf | Electromyography with prosthetic or orthotic devices |
Also Published As
Publication number | Publication date |
---|---|
EP1869728B1 (en) | 2014-02-26 |
EP1869728A2 (en) | 2007-12-26 |
EP1869728A4 (en) | 2013-01-09 |
WO2006098791A3 (en) | 2009-04-09 |
US20080165059A1 (en) | 2008-07-10 |
AU2005329042A1 (en) | 2006-09-21 |
USRE45061E1 (en) | 2014-08-05 |
US7646330B2 (en) | 2010-01-12 |
CA2600708A1 (en) | 2006-09-21 |
CA2600708C (en) | 2012-06-05 |
AU2005329042B2 (en) | 2009-08-27 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CA2600708C (en) | System and method for locating objects and communicating with the same | |
US9697714B2 (en) | Location of cooperative tags with personal electronic device | |
US7791470B2 (en) | Spin around direction and distance locator | |
US7573381B2 (en) | Reverse locator | |
US7592918B2 (en) | Electronic fence mode alert system and method | |
US7864045B2 (en) | Locator inventory system | |
US8384584B2 (en) | Reduced computation communication techniques for location systems | |
US8441391B2 (en) | Ultra-secure communication methods and apparatus | |
JP5524073B2 (en) | Tamper-proof freight container locator system | |
US9092678B2 (en) | Systems and methods to locate an object | |
CA2601088A1 (en) | System and method for locating objects and communicating with the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
WWE | Wipo information: entry into national phase |
Ref document number: 11885843 Country of ref document: US Ref document number: 13348507 Country of ref document: US |
|
ENP | Entry into the national phase |
Ref document number: 2600708 Country of ref document: CA |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2005329042 Country of ref document: AU |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2005854967 Country of ref document: EP |
|
NENP | Non-entry into the national phase |
Ref country code: RU |
|
ENP | Entry into the national phase |
Ref document number: 2005329042 Country of ref document: AU Date of ref document: 20051220 Kind code of ref document: A |