WO2019212408A1 - Système de télémétrie basé sur un radar pour le positionnement et la détection de signes vitaux - Google Patents

Système de télémétrie basé sur un radar pour le positionnement et la détection de signes vitaux Download PDF

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Publication number
WO2019212408A1
WO2019212408A1 PCT/SG2019/050234 SG2019050234W WO2019212408A1 WO 2019212408 A1 WO2019212408 A1 WO 2019212408A1 SG 2019050234 W SG2019050234 W SG 2019050234W WO 2019212408 A1 WO2019212408 A1 WO 2019212408A1
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Prior art keywords
signals
target object
carrier frequency
distance
phase
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PCT/SG2019/050234
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English (en)
Inventor
Yugang Ma
Yonghong Zeng
Sumei Sun
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Agency For Science, Technology And Research
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Priority to SG11202010695TA priority Critical patent/SG11202010695TA/en
Publication of WO2019212408A1 publication Critical patent/WO2019212408A1/fr

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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
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/36—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated with phase comparison between the received signal and the contemporaneously transmitted signal
    • G01S13/38—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated with phase comparison between the received signal and the contemporaneously transmitted signal wherein more than one modulation frequency is used
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/0205—Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves 
    • A61B5/0507—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves  using microwaves or terahertz waves
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/103—Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes
    • A61B5/11—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb
    • A61B5/113—Measuring movement of the entire body or parts thereof, e.g. head or hand tremor, mobility of a limb occurring during breathing
    • 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
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • G01S13/32—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S13/34—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
    • G01S13/347—Systems for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal using more than one modulation frequency
    • 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
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/50—Systems of measurement based on relative movement of target
    • G01S13/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
    • G01S13/583—Velocity or trajectory determination systems; Sense-of-movement determination systems using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets

Definitions

  • Various aspects of this disclosure generally relate to ranging of a target object, and more particularly, to positioning or ranging of a target object over a fine distance displacement of the target object.
  • Ranging/positioning is an essential technology that is needed in many applications from smart nation to smart factories.
  • the global navigation satellite system GNSS
  • GNSS global navigation satellite system
  • many demands in the smart nation and smart factories are in the indoor environment, where the GNSS is invalid.
  • UWB ultra- wideband
  • the Wi-Fi system (802.11 g) occupies narrower radio frequency (RF) bandwidth and uses lower sampling rate.
  • the ranging accuracy of a Wi-Fi time- of-arrival (ToA) method is as poor as a few meters. This is because that most of the ToA ranging/positioning solutions use the detection of signal edge.
  • the edge detection is directly related to the signal bandwidth and sampling speed for the signal. Since RF bandwidth is a valuable resource and high sampling speed usually results in high complexity and high power consumption, a ranging system having high accuracy but occupying narrow bandwidth with low sampling speed in intemet-of-things (IoT) applications is desirable.
  • Multi-frequency continuous wave (CW) radar was introduced for long distance ranging depending on phase information. However, only the phase of the beat between two carrier frequencies is used while the phase information of respective carrier are not be used.
  • a radar interferometry based phase detection for ranging of a target object is provided.
  • the method of ranging or positioning is based on a phase of a carrier frequency and a plurality of phases of beats among all frequencies.
  • the method may identify finer distance differences or displacements compared to the edge detection used in the common discrete time ToA/TDoA (time difference of arrival) solutions.
  • the method occupies a narrower RF bandwidth. Since the phase detection is not directly related to the sampling speed, high ranging accuracy may be achieved even with a low sampling rate.
  • positioning may be determined by multi-station trilateration or mono-station cooperating with direction of arrival (DoA) detection.
  • DoA direction of arrival
  • the method may be also suitable for vital sign detection because of its high sensitivity to distance changes, and in one example, detect the respiration rate of a moving object.
  • a multi-mode radar system based on the above method may be implemented readily using a SDR platform and advantageously, reconfigurable.
  • a method, a computer readable medium, and an apparatus for ranging a target object may transmit a plurality of signals with different frequencies towards the target object.
  • the apparatus may receive the plurality of signals as a result of the plurality of signals being reflected back from the target object.
  • the apparatus may estimate the phase of the basis carrier frequency signal of the plurality of signals and the number of periods traveled by the plurality of signals.
  • the apparatus may determine the distance to the target object based on the phase of the basis carrier frequency signal and the number of periods traveled by the plurality of signals.
  • the apparatus may estimate the moving speed of the target object or the vital sign frequency of the target object through monitoring the changing of the distance over time.
  • the one or more aspects include the features hereinafter fully described and particularly pointed out in the claims.
  • the following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.
  • FIG. 1 is a block diagram illustrating an example of a radar system.
  • FIG. 2A is a diagram illustrating an example of multiple frequencies being a sequence of frequencies changing along time.
  • FIG. 2B is a diagram illustrating an example of multiple frequencies emitted simultaneously.
  • FIG. 2C is a diagram illustrating an example of frequency synthesizer output.
  • FIG. 3 is a diagram showing the signal phases in different stages and different periods.
  • FIG. 4 is a diagram illustrating an example of the synchronization and initial pi calibration.
  • FIG. 5 is a chart illustrating mean ranging errors versus the signal to noise ratio of the method of one embodiment and the discrete time time-of-arrival method.
  • FIG. 6 is a chart illustrating the relationship of the ranging accuracy and the updating period.
  • FIG. 7 is a chart illustrating the mean ranging errors versus the signal to noise ratio of the method of one embodiment and the multi-frequency radar.
  • FIGS. 8 and 9 show the cumulative distribution functions of the method of one embodiment and the discrete time time-of-arrival method, respectively.
  • FIG. 10A is a diagram illustrating an example of positioning using a mono station equipped with an antenna array for direction al arrival estimation.
  • FIG. 10B is a diagram illustrating an example of positioning using three stations with trilateration.
  • FIG. 11 is a diagram illustrating an example of sensing human respiration rate using a radar of some embodiments.
  • FIG. 12 is a diagram illustrating the real detection results for the human respiration in time and frequency domains compared with that from a clinic-grade respiration sensor.
  • FIG. 13 is a diagram illustrating the detection results for a person walking from the radar to the place two meters in front of the radar, stopping for two seconds, and then walking back to the radar.
  • FIG. 14 is a signal processing block diagram in accordance with one embodiment of the present disclosure.
  • FIG. 15 is a signal processing block diagram in accordance with another embodiment of the present disclosure.
  • FIG. 16 is a flowchart of a method of ranging a target object.
  • FIG. 17 is a conceptual data flow diagram illustrating the data flow between different means/components in an exemplary apparatus.
  • FIG. 18 is a diagram illustrating an example of a hardware implementation for an apparatus employing a processing system. DETAILED DESCRIPTION
  • processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on a chip (SoC), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure.
  • processors in the processing system may execute software.
  • Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.
  • the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium.
  • Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer.
  • such computer-readable media may include a random- access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.
  • RAM random- access memory
  • ROM read-only memory
  • EEPROM electrically erasable programmable ROM
  • optical disk storage magnetic disk storage
  • magnetic disk storage other magnetic storage devices
  • combinations of the aforementioned types of computer-readable media or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.
  • FIG. 1 is a block diagram illustrating an example of a radar system 100.
  • the radar system 100 may be used to detect the distance to a target 102.
  • the radar system 100 may include a Tx (transmission) antenna 104, a Rx (receive) antenna 106, an RF front-end 120, and a software defined radio 1 10.
  • the emitted signal by the Tx antenna 104 may be represented as:
  • G( ⁇ ) cosCuqt) sin(iL> 2 t + Q) + sin(n> 1 t) cos ( ⁇ n 2 t + Q ) (1) where Q is the initial phase at the emission start moment.
  • the emitted signal hits the target 102, and the reflection is received by the Rx antenna 106 after the round-way travelling time t.
  • the received signal is:
  • R(t) fcosCuiit— w ⁇ t) sin(io 2 t + q— w 2 t) + sinCa ⁇ t— w ⁇ t) cos (co 2 t + Q— w 2 t)] + n(t) (2)
  • p is the propagation loss compared with the emitted signal
  • 77. (t) is the additive white Gaussian noise (AWGN).
  • n'(t) is the AWGN after the low pass filter 124.
  • n'"(t) n'(t) [sin(aqt) + cos(aqt)].
  • Equation (11) is the finest level of distance estimation. It is based on interferometry. The detection accuracy is related to the signal frequency instead of its bandwidth.
  • the signal parts of Y and X in equations (7) and (8) do not include “t” whose accuracy is effected by sampling speed. Instead, they include only“T” which is independent to“t”. In other words, Y and X are not effected by sampling rate. Accordingly, the estimation of t is not related to sampling rate. As a result, high accuracy wireless positioning may be achieved without occupying large RF bandwidth and high sampling rate.
  • Equation (9) the distance estimation in Equation (9) will periodically repeat in any multiple of the signal wavelength.
  • Table 1 summarizes the detection sensitivities and ranges for different carrier frequencies. These sensitivities are enough for detecting most of vital signs.
  • the weak vital sign such as heart beat may use high carrier frequency, for example 60GHz, while for the respiration detection, low carrier frequency such as 2.4GHz may be used.
  • Equation (11) gives the estimation of short distance within half signal wavelength.
  • the distance detection range is not enough for most positioning applications.
  • multiple frequencies may need to be used.
  • the radar system 100 emits multiple frequencies, the range between the radar and the target 102 may be derived from the different phase shifts corresponding to different frequencies.
  • the distance estimation of some embodiments is as follows. Recalling the output X and Y for emission signal (a1 ⁇ 2 + w 2 ), they may be represented in the complex format
  • n c (t) is the complex AWGN from radar branches X and Y.
  • w 1 ⁇ is the value of o ⁇ in stage f
  • q t to 6 W are the fixed phase differences among multiple frequencies caused by the frequency synthesiser.
  • FIG. 2A is a diagram 200 illustrating an example of multiple frequencies being a sequence of frequencies changing along time.
  • the frequency increases from stage 1 to stage W in a period, i.e., w ⁇ w 1 ⁇ ⁇ co lw , then repeating the same pattern in subsequent periods.
  • FIG. 2B is a diagram 220 illustrating an example of multiple frequencies emitted simultaneously.
  • the frequency increases from stage 1 to stage W, i.e., w i ⁇ w 1£ ⁇ t l w .
  • FIG. 2C is a diagram 240 illustrating an example of frequency synthesizer output.
  • the frequency increases from stage 1 to stage W in a period, i.e., o> 11 ⁇ w a ⁇ ) iw , then repeating the same frequency pattern in subsequent periods.
  • FIG. 3 is a diagram 300 showing the signal phases in different stages and different periods. Note that the phase differences among different stages increase along with distance increasing. This information may be used to estimate the distance. Let the phase in stage 1 in period 1 is p , then the phase in stage i in period 1 is
  • range estimation consists of the estimate to N and the estimate to p ⁇ in one period. Both estimates may be jointly achieved by using the least-square approach.
  • F may be represented as a function of , p ⁇ and stage i
  • a W x W diagonal matrix L may be defined to denote all stages’ phase shifting effects caused by large delays as
  • a lf x l column vector 5 may be defined to denote all stages’ phase shifting effects caused by small delays as
  • a W x 1 column vector F may be defined to denote all stages’ observed phases as
  • N is a W x 1 column vector consisting of AWGN in W stages.
  • F j is the observation of F in stage i, b is the least common multiple between two frequencies having smallest frequency difference among W stages.
  • b is defined by the maximum possible round-trip distance divided by signal l of stage W in the working area. For example, if the maximum consider distance is 100 meters, and the basis frequency is 2.4 GHz,
  • Equation (20) Compared with the multi-frequency CW radar in Equation (9), Equation (20) includes pi, and jointly estimates N with all phase information, while the one in Equation (9) separately estimates the phase of the beat between two frequencies without the phase estimation for the basis carrier frequency.
  • Equation (20) requires heavy computation due to two-dimension search.
  • the estimation accuracy is also restricted by the search step-size for p ⁇ . Thus, it is not practical.
  • X 1 and Y 1 are the radar outputs of X and Y in stage 1.
  • F t is the observation waveform at stage i.
  • Equation (22) is one-dimension integer search, the computation is much less than that of Equation (20).
  • round(.) means rounding to the nearest integer.
  • Equation (22) The estimation for N using Equation (22) is more accurate in theory, but Equation (22)
  • the software defined radio clock is synchronized to carrier frequency w 2 through the phase-locked loop (PLL) so as to secure that and w 2 have fixed phase difference in Equation (l5a). They are all coherent to each other thanks to the mechanism. The remained fixed phase errors among different local frequencies may be calibrated.
  • PLL phase-locked loop
  • FIG. 4 is a diagram 400 illustrating an example of the synchronization and initial pi calibration.
  • the radar may include a software defined radio 410 and an RF front-end 420.
  • the software defined radio 410 and the RF front- end 420 may be the software defined radio 1 10 and the RF front-end 120, respectively, described above with reference to FIG. 1.
  • the RF front-end 420 includes an LO 428 and a PLL 422.
  • the software defined radio 410 includes a phase shifter 416 and an LO 412.
  • the LO 412 and the LO 428 may be synchronized through the PLL 422.
  • the performance of the ranging of an embodiment is simulated and compared to discrete-time based ToA method.
  • the radar system of the embodiment emits 2.4 GHZ and 2.401 GHz sequentially.
  • the filter bandwidth in RF front-end is 2 MHz.
  • the sampling rate is 5 MHz.
  • the signal to noise ratio (SNR) is defined dB of the signal power divided by the noise power in the respective signal bandwidth for different systems.
  • the distance for estimations in the simulation was randomly generated from 0 to 100 meters.
  • FIG. 5 is a chart 500 illustrating mean ranging errors versus SNR of the method of one embodiment and the discrete time ToA method.
  • the discrete time TOA method have the error floor, which means that no matter how high SNR is, the ranging accuracy cannot be improved ln contrast, the method of one embodiment has smaller ranging error when SNR is larger than -10 dB even the signal bandwidth is one tenth of the discrete time TOA method.
  • the ranging error may be improved with increased SNR.
  • FIG. 6 is a chart 600 illustrating the relationship of the ranging accuracy and the updating period. As shown, the method of one embodiment has improved accuracy by increasing the ranging updating period. However, due to the error floor, the discrete time ToA method cannot be improved in the practical SNR range.
  • FIG. 7 is a chart 700 illustrating the mean ranging errors versus SNR of the method of one embodiment and the multi-frequency radar (update period 10 s). As shown, the method of one embodiment achieves much more accurate ranging if the time accumulation is long enough.
  • FIGS. 8 and 9 show the cumulative distribution functions (CDFs) of the method of one embodiment and the discrete time ToA method, respectively.
  • the updating period here is 10 ms.
  • the method of one embodiment achieves 0.7 meter accuracy with 95% probability when the SNR is 10 dB.
  • the discrete time ToA method achieves only 3.2 meter accuracy. If the SNR is increased to 20 dB, 95% ranging accuracies for the method of one embodiment and the discrete time ToA are 0.3 meter and 3.2 meters, respectively.
  • Positioning may be achieved by using mono station equipped with an antenna array for direction of arrival (DoA) estimation or multiple stations with trilateration. Each station may be equipped with a radar described above with reference to FIGS. 1-9 to performing ranging.
  • FIG. 10A is a diagram 1000 illustrating an example of positioning using a mono station 1002 equipped with an antenna array for direction al arrival estimation.
  • FIG. 10B is a diagram 1050 illustrating an example of positioning using three stations 1052, 1054, and 1056 with trilateration.
  • the target to be positioned may be passive, which require the station emits relative larger power to secure enough reflection strength.
  • the positioned targets may be active reflectors.
  • the station emits the signal for ranging including the called target ID.
  • the target When the target received the call, and the ID is matched, the target will resend the received signal back after a fixed delay. This makes the radar receiving strong enough reflection signal.
  • the system may position multiple targets sequentially.
  • the ranging method of some embodiments may also be used in vital sign detection. Since the interferometry in Equation (1 1) may detect very fine distance turbulence. This may be used to test the vital sign such us respiration rate and moving speed.
  • the radar system of some embodiments may be used to detect the human respiration rate by facing the radar’s Tx and Rx antennas to a human’s chest.
  • FIG. 11 is a diagram 1100 illustrating an example of sensing human respiration rate using a radar 1102 of some embodiments.
  • the radar architecture of some embodiments implemented in the GNU radio and processing with Equation (11), accurate detection may be achieved.
  • FIG. 12 is a diagram 1200 illustrating the real detection results for the human respiration in time and frequency domains compared with that from a clinic-grade respiration sensor.
  • the measured respiration rates were 0.2601 Hz by the system of one embodiment and 0.25 Hz by of the clinic-grade respiration sensor, respectively. Comparing the results by two approaches, the difference of two detections for the respiration rate was less than 5%.
  • the radar emission power was -14 dBm.
  • the radar system of some embodiments may be used to detect the moving object and its speed.
  • Equation (7) if the reflection is from a moving object, r will be a time- varying variable as follows
  • ri j (t) is the complex noise caused by branches X and Y.
  • the Doppler frequency can be estimated as
  • T(f) is the Fourier transform of F(t).
  • FIG. 13 is a diagram 1300 illustrating the detection results for a person walking from the radar to the place two meters in front of the radar, stopping for two seconds, and then walking back to the radar.
  • a threshold may be set for the output of the Doppler frequency detection, e.g., 3 FIz, so as to filter out the random noise.
  • the Tx emission power is -3.5 dBm.
  • FIG. 14 is a signal processing block diagram 1400 in accordance with one embodiment of the present disclosure. As shown, each of signal parts X and Y goes through a first-in-first-out (FIFO) queue 1402 and 1404, respectively.
  • FIFO first-in-first-out
  • the outputs of FIFO queues 1402 and 1404 may be sent to a Cartesian-polar coordinate converter 1406, which outputs pi.
  • the output of the Cartesian-polar coordinate converter 1406 may be provided to a band pass filter (BPF) 1408, which outputs an estimate of breath signal.
  • BPF band pass filter
  • the outputs of FIFO queues 1402 and 1404 may be sent to a fast Fourier transform (FFT) unit 1410, which perform fast Fourier transformation.
  • FFT fast Fourier transform
  • the frequency having peak output may be identified based on the output of the FFT unit 1410.
  • the estimate of moving speed may be calculated based on Equation (31).
  • the waveforms F(iV, , i) may be calculated according to p ⁇ .
  • the observation waveforms Ft to Fw may be formed based the signal parts X and Y.
  • the value of N may be changed and the N that makes having minimum output value may be identified.
  • ranging estimate may be calculated based on p and N in accordance with Equation (24).
  • FIG. 15 is a signal processing block diagram 1500 in accordance with another embodiment of the present disclosure. Such embodiment may be suitable for the case where the spaces between two adjacent tones are constant.
  • each of signal parts X and Y goes through a first-in- first-out (FIFO) queue 1502 and 1504, respectively.
  • the outputs of FIFO queues 1502 and 1504 may be sent to a Cartesian-polar coordinate converter 1506, which outputs p(.
  • the output of the Cartesian-polar coordinate converter 1506 may be provided to a BPF 1508, which outputs an estimate of breath signal.
  • the outputs of FIFO queues 1502 and 1504 may be sent to a FFT unit 1510, which perform fast Fourier transformation.
  • the frequency having peak output may be identified based on the output of the FFT unit 1510.
  • the estimate of moving speed may be calculated based on Equation (31).
  • the observation waveforms F / to Fw may be formed based the signal parts X and Y.
  • FIG. 16 is a flowchart 1600 of a method of ranging a target object.
  • the method may be performed by an apparatus (e.g., apparatus 1702/1702’ described below with reference to FIG. 17 or 18).
  • the apparatus may be part of a radar system.
  • the operations performed in the method may correspond to operations described above with reference to FIGS. 1-4, 10A, 10B, 11, 14, and 15.
  • the apparatus may transmit a plurality of signals with different frequencies towards a target object.
  • the plurality of signals may have a sequence of frequencies changing along time in a period.
  • the plurality of signals may have different frequencies and may be simultaneously emitted.
  • the plurality of signals may correspond to a plurality of stages with ascending frequencies in a period.
  • the basis carrier frequency signal may have the lowest frequency among the plurality of signals.
  • the basis carrier frequency signal may have the same phase in each period.
  • the apparatus may receive the plurality of signals as a result of the plurality of signals being reflected back from the target object.
  • the plurality of received signals may be a plurality of analog signals.
  • the apparatus may further remove high frequency components from the plurality of analog signals before converting the plurality of analog signals into a plurality of digital signals for further processing.
  • the target object may be an active reflector that resends the plurality of signals back after a fixed delay subsequent to receiving the plurality of signals at the target object.
  • the apparatus may estimate the phase of the basis carrier frequency signal of the plurality of signals and the number of periods traveled by the plurality of signals.
  • the phase of the basis carrier frequency signal and the number of periods traveled by the plurality of signals may be estimated separated.
  • the apparatus may determine the distance to the target object based on the phase of the basis carrier frequency signal and the number of periods traveled by the plurality of signals.
  • the accuracy of the determined distance may be independent of the bandwidth of the plurality of signals and the sampling rate of the plurality of signals.
  • the apparatus may estimate the moving speed of the target object or the vital sign frequency of the target object through monitoring the changing of the distance over time.
  • the detection sensitivity for the changing of the distance may increase when the carrier frequency of the plurality of signals increases.
  • the detection range for the changing of the distance may narrow when the carrier frequency of the plurality of signals increases.
  • FIG. 17 is a conceptual data flow diagram 1700 illustrating the data flow between different means/components in an exemplary apparatus 1702.
  • the apparatus 1702 may be a radar or part of a radar.
  • the apparatus 1702 may include a reception component 1704 that receives reflected signals from a target object 1750.
  • the reception component 1704 may perform the operations described above with reference to 1604 in FIG. 16.
  • the apparatus 1702 may include a transmission component 1710 that transmits probing signals to the target object 1750.
  • the transmission component 1710 may perform the operations described above with reference to 1602 in FIG. 16.
  • the reception component 1704 and the transmission component 1710 may collaborate to coordinate the communication of the apparatus 1702.
  • the apparatus 1702 may include a ranging component 1706 that is configured to perform ranging on the target object based on the received reflected signals.
  • the ranging component 1706 may perform the operations described above with reference to 1606 or 1608 in FIG. 16.
  • the apparatus 1702 may include a vital sign component 1708 that is configured to estimate the moving speed of the target object 1750 or the vital sign frequency of the target object 1705 via monitoring the changing of the distance provided by the ranging component 1706.
  • the vital sign component 1708 may perform the operations described above with reference to 1610 in FIG. 16.
  • the apparatus 1702 may include additional components that perfonn each of the blocks of the algorithm in the aforementioned flowchart of FIG. 16. As such, each block in the aforementioned flowchart of FIG. 16 may be performed by a component and the apparatus may include one or more of those components.
  • the components may be one or more hardware components specifically configured to carry out the stated proeesses/algorithm, implemented by a processor configured to perfonn the stated processes/algorithm, stored within a computer-readable medium for implementation by a processor, or some combination thereof.
  • FIG. 18 is a diagram 1800 illustrating an example of a hardware implementation for an apparatus 1702' employing a processing system 1814.
  • the apparatus 1702’ may be the apparatus 1702 described above with reference to FIG. 17.
  • the processing system 1814 may be implemented with a bus architecture, represented generally by the bus 1824.
  • the bus 1824 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 1814 and the overall design constraints.
  • the bus 1824 links together various circuits including one or more processors and/or hardware components, represented by the processor 1804, the components 1704, 1706, 1708, 1710 and the computer-readable medium / memory 1806.
  • the bus 1824 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.
  • the processing system 1814 may be coupled to a transceiver 1810.
  • the transceiver 1810 is coupled to one or more antennas 1820.
  • the transceiver 1810 provides a means for communicating with various other apparatus over a transmission medium.
  • the transceiver 1810 receives a signal from the one or more antennas 1820, extracts infonnation from the received signal, and provides the extracted information to the processing system 1814, specifically the reception component 1704.
  • the transceiver 1810 receives infonnation from the processing system 1814, specifically the transmission component 1710, and based on the received infonnation, generates a signal to be applied to the one or more antennas 1820.
  • the processing system 1814 includes a processor 1804 coupled to a computer- readable medium / memory 1806.
  • the processor 1804 is responsible for general processing, including the analyzation of data gathered by the apparatus itself through its own sensors and the execution of software stored on the computer-readable medium / memory 1806.
  • the software when executed by the processor 1804, causes the processing system 1814 to perform the various functions described supra for any particular apparatus.
  • the computer- readable medium / memory 1806 may also be used for storing data that is manipulated by the processor 1804 when executing software.
  • the processing system 1814 further includes at least one of the components 1704, 1706, 1708, 1710.
  • the components may be software components running in the processor 1804, resident/stored in the computer readable medium / memory 1806, one or more hardware components coupled to the processor 1804, or some combination thereof.
  • Example 1 is a method or apparatus for ranging a target object.
  • the apparatus may transmit a plurality of signals with different frequencies towards the target object.
  • the apparatus may receive the plurality of signals as a result of the plurality of signals being reflected back from the target object.
  • the apparatus may estimate the phase of the basis carrier frequency signal of the plurality of signals and the number of periods traveled by the plurality of signals.
  • the apparatus may determine the distance to the target object based on the phase of the basis carrier frequency signal and the number of periods traveled by the plurality of signals.
  • Example 2 the subject matter of Example 1 may optionally include that the accuracy of the detennined distance may be independent of the bandwidth of the plurality of signals and the sampling rate of the plurality of signals.
  • Example 3 the subject matter of any one of Examples 1 to 2 may optionally include that the phase of the basis carrier frequency signal and the number of periods traveled by the plurality of signals may be estimated separated.
  • Example 4 the subject matter of any one of Examples 1 or 3 may optionally include that the apparatus may further estimate the moving speed of the target object or the vital sign frequency of the target object through monitoring the changing of the distance over time.
  • Example 5 the subject matter of Example 4 may optionally include that the detection sensitivity for the changing of the distance may increase when the carrier frequency of the plurality of signals increases, where the detection range for the changing of the distance may narrow when the carrier frequency of the plurality of signals increases.
  • Example 6 the subject matter of any one of Examples 1 to 5 may optionally include that the plurality of received signals may be a plurality of analog signals, where the apparatus may further remove high frequency components from the plurality of analog signals before converting the plurality of analog signals into a plurality of digital signals for further processing.
  • Example 7 the subject matter of any one of Examples 1 or 6 may optionally include that the plurality of signals may have a sequence of frequencies changing along time in a period.
  • Example 8 the subject matter of any one of Examples 1 to 7 may optionally include that the plurality of signals may have different frequencies and are simultaneously emitted.
  • Example 9 the subject matter of any one of Examples 1 or 8 may optionally include that the plurality of signals may correspond to a plurality of stages with ascending frequencies in a period, where the basis carrier frequency signal may have the lowest frequency among the plurality of signals, where the basis carrier frequency signal may have the same phase in each period.
  • Example 10 the subject matter of any one of Examples 1 to 9 may optionally include that the target object may be an active reflector that resends the plurality of signals back after a fixed delay subsequent to receiving the plurality of signals at the target object.
  • the target object may be an active reflector that resends the plurality of signals back after a fixed delay subsequent to receiving the plurality of signals at the target object.
  • Combinations such as“at least one of A, B, or C,”“one or more of A, B, or C,”“at least one of A, B, and C,”“one or more of A, B, and C,” and“A, B, C, or any combination thereof’ include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C.
  • combinations such as“at least one of A, B, or C,”“one or more of A, B, or C,”“at least one of A, B, and C,”“one or more of A, B, and C,” and“A, B, C, or any combination thereof’ may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C.

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Abstract

La présente invention concerne une détection de phase basée sur l'interférométrie radar pour la télémétrie d'un objet cible. Le procédé de télémétrie ou de positionnement est basé sur une phase d'une fréquence de porteuse et une pluralité de phases de battements parmi toutes les fréquences. Après la télémétrie, le positionnement peut être déterminé par trilatération multistation ou monostation en coopération avec la détection de direction d'arrivée. Le procédé peut également être adapté pour la détection de signes vitaux en raison de sa sensibilité élevée à des changements de distance et, dans un exemple, pour détecter la fréquence respiratoire d'un objet mobile.
PCT/SG2019/050234 2018-04-30 2019-04-26 Système de télémétrie basé sur un radar pour le positionnement et la détection de signes vitaux WO2019212408A1 (fr)

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Publication number Priority date Publication date Assignee Title
CN117420538A (zh) * 2023-12-18 2024-01-19 深圳捷扬微电子有限公司 一种超宽带系统的测距方法
CN117420538B (zh) * 2023-12-18 2024-03-08 深圳捷扬微电子有限公司 一种超宽带系统的测距方法

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