TWI768772B - Frequency modulated continuous wave radar system and identity and information detection method thereof - Google Patents

Abstract

A frequency modulated continuous wave radar system includes at least one identity tag, respectively disposed next to at least one test subject; and a frequency modulated continuous wave radar identity recognition device, including an identity recognition control module, for controlling a test identity tag of the at least one identity tag to be tumed on to generate a specific tag reflection signal corresponding to an identity frequency in response to a chirp signal; and a frequency modulated continuous wave radar, for transmitting the chirp signal and receiving at least one reflection signal of the at least one test subject and the specific tag reflection signal in response to the chirp signal, to calculate and determine that the specific tag reflection signal and a specific reflection signal of the at least one reflection signal are corresponding to an adjacent position information. The specific reflection signal is corresponding to test subject information.

Description

Frequency Modulated Continuous Wave Radar System and Its Identity and Information Detection Method

The present invention relates to a frequency-modulated continuous wave radar system and a method for detecting its identity and information, in particular to a tag reflector capable of activating a specific identity tag with an identity frequency to obtain a subject to be measured adjacent to the specific identity tag. A FM continuous wave radar system for information and a method for detecting its identity and information.

In recent years, Vital Sign detection technology has developed vigorously (such as infrared body temperature measurement, blood glucose concentration detection, blood oxygen concentration detection), including non-personal use of physiological information detection. For example, the non-contact heartbeat and respiration rate detection device can transmit a radio frequency (RF) signal to the subject and receive the corresponding reflected signal. and body displacement caused by breathing). After receiving, demodulating, filtering and amplifying the reflected signal, the algorithm inside the processor can calculate the heartbeat and respiratory rate of the test subject.

However, although the conventional continuous wave (CW) radar technology can remotely measure the physiological information such as the breathing and heartbeat of the test subject, it is difficult to correctly detect the physiological information such as the breathing and heartbeat of the specified test subject in a group of people. The reflected signal interference caused by adjacent people or objects is serious, which increases the difficulty of measurement.

In view of this, it is necessary to improve the prior art.

Therefore, the main purpose of the present invention is to provide a tag reflector capable of activating a specific identification tag with an identification frequency, so as to obtain the information of the subject to be measured adjacent to the specific identification tag. A frequency modulated continuous wave radar system and its identity and information detection method.

The present invention discloses a frequency-modulated continuous wave radar system, comprising at least one identity label, respectively disposed beside at least one person to be tested; and a frequency-modulated continuous wave radar identity recognition device, comprising an identity recognition control module for sending a control The signal controls an identity tag to be tested in the at least one identity tag to be turned on, so that the specific identity tag generates a specific tag reflection signal corresponding to an identity frequency in response to a chirp signal; and a FM continuous wave radar for transmitting the linear frequency modulation signal. FM signal, and receive at least one reflected signal of the at least one subject and the specific label reflected signal in response to the chirp signal, to calculate and determine the specific label reflected signal and a specific reflected signal among the at least one reflected signal Corresponding to a similar position information; wherein, the specific reflected signal corresponds to a test subject information.

The present invention further discloses an identity and information detection method for a frequency modulation continuous wave radar system, comprising disposing at least one identity tag next to at least one to-be-tested person respectively; sending a control signal to control one of the at least one identity tag to be tested An FM CW radar transmits a chirp signal; the specific identity tag generates a specific tag reflection signal corresponding to an identity frequency in response to the chirp signal; and the FM CW radar receives a response to the chirp signal Signal at least one reflected signal of the at least one test subject and the specific label reflected signal to calculate and determine that the specific label reflected signal and a specific reflected signal of the at least one reflected signal correspond to a similar position information; wherein, the The specific reflected signal corresponds to a test subject information.

10: FM continuous wave radar

100: Chirp Synthesizer

102: Transmitting Antenna

104: Receiving Antenna

106: Low-pass filter (or band-pass filter)

108: Analog-to-digital converters

110: Processor

112: Mixer

30,40: Frequency Modulated Continuous Wave Radar Systems

32: FM continuous wave radar identification device

300: Identification Control Module

302: FM CW Radar

304: Tag Antenna

306: Tag wireless communication unit

308: Label Controller

310: Label Reflector

312: Control Unit

314: Wireless Communication Unit

316: Control Antenna

318: Chirp Synthesizer

320: transmitter circuit

322: Transmitting Antenna

324: Receive Antenna

326: Receiver circuit

328: demodulation unit

330: Analog to Digital Converter

332: Operation processing unit

50: Process

500~524: Steps

700, 702: Sub-receiving antenna

TX,TX': Chirp signal

RX: Reflected signal

IF,IF’: Intermediate frequency signal

IDT, IDT1~IDTn: identity tag

RXH, RXH1~RXHn: Reflected signal

RXT, RXT1~RXTn: Tag reflected signal

CON: control signal

M1~M3: Matrix

Tc: period

Figure 1 is a schematic diagram of a FM continuous wave radar.

FIG. 2A is a schematic diagram of a chirp signal versus time.

FIG. 2B is a schematic diagram of a chirp signal, a reflected signal, and an IF signal.

FIG. 3 is a schematic diagram of an FM continuous wave radar system according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of the operation of another FM continuous wave radar system according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of an identity and information detection process according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of the operation of an arithmetic processing unit according to an embodiment of the present invention.

FIG. 7 is a schematic diagram of determining the angle of arrival of the reflected signal of the chirp signal according to an embodiment of the present invention.

Please refer to FIG. 1 , which is a schematic diagram of a Frequency Modulated Continuous Wave (CW) radar 10 . The difference between the FM continuous wave radar 10 and the continuous wave radar is that the continuous wave radar transmits signals of the same frequency continuously, and the FM continuous wave radar 10 transmits the modulated frequency signal. To put it simply, the FM CW radar 10 includes a Chirp Synthesizer 100 for generating a chirp signal TX, which is then transmitted through a transmitting circuit through a transmitting antenna 102 . When the chirp signal TX hits an object (such as the subject to be tested), a reflected signal RX is generated. The reflected signal RX is received by a receiving antenna 104 and then coupled via a mixer (Mixer) 112. At this time, the chirp signal TX and the receiving antenna 104 are coupled. The received reflected signal RX, the coupled output signal passes through a Low Pass Filter or Band Pass Filter 106 to filter out high frequency signals (such as the chirp signal TX and the reflected signal RX) , generates an intermediate frequency signal IF, and then converts it into a digital signal through an analog to digital converter (ADC) 108, and then processes it by a processor 110 to obtain distance, direction and physiological information (Vital Sign).

Please refer to FIGS. 2A and 2B. FIG. 2A is a schematic diagram of the chirp signal TX versus time, and FIG. 2B is a schematic diagram of the chirp signal TX, the reflected signal RX, and the intermediate frequency signal IF. In detail, as shown in the lower half of Fig. 2A, the frequency of the chirp signal TX increases linearly with a modulation slope S with time, so as shown in the upper half of Fig. 2A, the chirp signal TX in the time domain As shown in the upper half of Figure 2B, the reflected signal RX starts to be received at a time τ after the chirp signal TX is transmitted, so as shown in the lower half of Figure 2B, it can be obtained with a frequency S τ Intermediate frequency signal IF, its relationship can be expressed as follows: TX= _AT sin( w ₁ t +Φ ₁ )

RX= _AR sin( w ₂ t +Φ ₂ )

IF=A _B sin(( w ₁ - w _z ) t +(Φ ₁ -Φ ₂ ))=A _B sin(2π f ₀ ) t +Φ ₀ )

f ₀ = f ₁ - f ₂ =Sτ=2Sd/C

Φ ₀ =(2π * 2d)/λ=4πd/λ

τ=2d/C

Wherein, d is the distance between the test subject and the FM CW radar 10, C is the signal propagation speed (speed of light), and other expressions of amplitude, angular velocity, phase, frequency, and wavelength are well known in the art, and will not be repeated here. It can be seen from the above equation that the information of the frequency f ₀ of the intermediate frequency signal IF implies the distance d of the test subject, and the phase Φ ₀ of the intermediate frequency signal IF implies the physiological information such as the subject's breathing and heartbeat (due to breathing, heartbeat, etc.). The resulting body displacement is about 1-2mm, and the frequency is not affected only in one millimeter wave wavelength of 12.5mm cycle), so the processor 110 can obtain the distance, direction, breathing, and heartbeat of the subject through calculation.

On the other hand, please refer to FIG. 3 , which is a schematic diagram of a FM continuous wave radar system 30 according to an embodiment of the present invention. The FM CW radar system 30 includes an identity tag (identity tag) IDT and an FM CW radar identification device 32. The FM CW radar identification device 32 includes an identification control module 300 and an FM CW radar 302. The identity tag The IDT includes a tag antenna 304, a tag wireless communication unit 306, a tag controller 308, and a tag reflector 310. The identification control module 300 includes a control unit 312, a wireless communication unit 314, and a control antenna 316. FM CW radar 302 includes a chirp 318, a transmit circuit 320, a transmit antenna 322, a receive antenna 324, a receive circuit 326, a demodulation unit 328, an analog-to-digital converter 330, and an arithmetic processing unit 332 .

In short, the operation of the FM CW radar 302 is similar to the operation of the FM CW radar 10 to obtain the distance, direction, breathing, and heartbeat of the test subject. The main difference between the FM CW radar system 30 and the FM CW radar 10 is That is, the FM CW radar system 30 will be able to turn on or off the identification mark The tag IDT (the tag reflector 310 can cause a tag reflection signal RXT to have a phase change corresponding to an identity frequency after it is turned on) is set around the subject, and then the identity recognition control module 300 sends a The control signal CON controls the identity tag IDT to be turned on. After the FM continuous wave radar 302 sends a chirp signal TX', it can receive a reflection signal RXH of the test subject and a tag reflection signal RXT of the identity tag IDT for processing, so as to obtain The distance, direction and physiological information (respiration, heartbeat) of the test subject, as well as the distance, direction and identity frequency of the ID tag IDT. In this case, since the unopened identity tag does not reflect the reflected signal of the tag with identity information (such as identity frequency), the FMCW radar 302 can calculate the physiological information of the test subject and the identity tag IDT at the same distance and direction. Combined, you can know which person's physiological information is the measured breathing and heartbeat physiological information. In this way, the present invention can activate the tag reflector of the specific identification tag to have the identification frequency, so as to obtain the physiological information of the subject to be measured adjacent to the specific identification tag.

For example, please refer to FIG. 4 , which is a schematic diagram of the operation of an FM continuous wave radar system 40 according to an embodiment of the present invention. The FM CW radar system 40 is roughly the same as the FM CW radar system 30, so components and signals with similar functions are represented by the same symbols for simplicity. The main difference between the FM CW radar system 40 and the FM CW radar system 30 is that the frequency modulation The continuous wave radar system 40 includes different identification tags IDT1~IDTn (which have the same structure as the identification tag IDT) and are respectively disposed next to different test subjects (such as hands), so the identification control module 300 sends a control signal CON through wireless communication. In the case of controlling an identity tag IDT2 to be tested to be turned on (corresponding to the identity frequency) and the other identity tags are turned off, after the FM continuous wave radar 302 sends the chirp signal TX', it can receive the test subject responding to the chirp signal TX' One reflected signal RXH1~RXHn and one label reflected signal RXT2 of the identity label IDT2 corresponding to the identity frequency are processed (the label reflected signals of other identity labels represented by dotted lines do not correspond to the identity frequency and cannot be detected), so the frequency modulation is continuous. The wave radar 302 can calculate and determine that the reflected signal RXH2 and the tag reflected signal RXT2 correspond to the nearby position information (distance, direction), and can obtain the physiological information corresponding to the subject's respiration, heartbeat and waiting for the subject to be measured from the reflected signal RXH2 .

Please continue to refer to Figure 3. Specifically, the control unit 312 is the control center of the FM CW radar identification device 32, and can communicate wirelessly with the tag antenna 304 of the ID tag IDT and the tag wireless communication unit 306 through the wireless communication unit 314 and the control antenna 316, and instructs The tag controller 308 of the identity tag IDT activates or deactivates the tag reflector 310 , wherein the wireless communication may use Radio Frequency Identification (RFID), WIFI, Bluetooth, ZigBee or other wireless communication technologies.

Next, the control unit 312 can control the FM CW radar 302 to perform FM CW detection. The FMCW radar 302 operates similarly to the FMCW radar 10. The chirp synthesizer 318 can generate a chirp signal TX', and each chirp sub-signal in the chirp signal TX' can be as shown in FIG. 2A. The radio frequency oscillation signal with the start frequency of 77GHz and the stop frequency of 81GHz has a time period of 40μs and a modulation slope S of 100MHz/μs, but other signal specifications (such as a start frequency of 24GHz) are also available. Then, the transmitting circuit 320 includes a power amplifier (PA), which can amplify the chirp signal TX' and transmit it through the transmitting antenna 322, wherein the design of the transmitting antenna 322 is related to the radio frequency used, the effective transmission angle ( field of view, FOV) related.

With the tag reflector 310 activated, when the identity tag IDT receives the chirp signal TX', a tag reflection signal RXT corresponding to the identity frequency may be generated in response to the chirp signal TX'. Therefore, the receiving antenna 324 can receive the reflected signal of the chirp signal TX' transmitted by the transmitting antenna 322 (including the reflected signal of touching the human body, the identity tag IDT, and the stationary or moving objects in the environment), and then the receiving circuit 326 can detect the reflected signal. The reflected signal is subjected to front-end signal amplification and front-end filtering. It should be noted that the design of the receiving antenna 324 needs to consider the frequency range of the received radio frequency signal and whether it is necessary to identify the direction of the object to be measured.

In this case, although the dominant frequency of the different reflected signals is the same as the chirp signal TX', the different reflected signals have different characteristics. For example, the reflection intensity of different objects is different (human body or metal has a strong reflection intensity), and the reflection signal RXH generated by the chest displacement caused by the coupling of body breathing and heartbeat The phase change corresponds to a specific physiological frequency, and the tag reflection signal RXT corresponds to a specific identity frequency (such as the vibration frequency of a vibrator in the tag reflector 310, a rotation frequency of a motor, or a radar cross-section (Radar Cross-Section, RCS). modulation frequency, etc.), and the reflected signals at different distances have different modulation frequency differences.

In addition, the demodulation unit 328 can demodulate (eg couple) the current chirp signal TX' generated by the chirp synthesizer 318 and the reflected signal (including the reflected signal RXH and the tag reflected signal RXT) received by the receiving circuit 326, The demodulated signal is removed through a low-pass filter to remove radio frequency signals (such as the chirp signal TX', the reflected signal RXH and the label reflected signal RXT) to obtain an intermediate frequency signal IF'. Next, the analog-to-digital converter 330 converts the intermediate frequency signal IF' in the analog form into a digital form, which is convenient for the operation processing unit 332 to process. Then, the arithmetic processing unit 332 uses various digital processing algorithms to remove noises, high-frequency signals and inappropriate breathing harmonics, so as to calculate the distance, direction, and identity information (eg, identity frequency) of the identity tag IDT to be detected. , Human distance and breathing, heartbeat waiting for the physiological information of the tester. Finally, the control unit 312 compares the distance and the direction to find the identity information of the identity tag IDT and the physiological information of the human body breathing and heartbeat waiting for the same (close) distance (and/or direction), so as to determine the physiological information ( Respiration, heartbeat) belong to the test subject corresponding to the identity tag IDT (or are compared by the arithmetic processing unit 332, and the two can also be integrated into a single processor).

The operations of the FM CW radar systems 30 and 40 described above can be summarized as an identity and information detection process 50 . Specifically, please refer to FIG. 5, which is a schematic diagram of an identity and information detection process 50 according to an embodiment of the present invention. As shown in FIG. 5, the FM CW radar identification device 32 can search for the identification tags IDT1~IDTn through the wireless communication unit 314, and control the identification tag IDT2 to be turned on (step 502), so that the identification tag IDT2 to be tested is turned on to activate a The corresponding label reflector has an identity frequency (step 504), wherein the identity frequency is a vibration frequency of a vibrator, a rotation frequency of a motor, or a Radar Cross-section in the corresponding label reflector. Section, RCS) one of the modulation frequency. Next, the FM CW radar identification device 32 starts the FM CW radar 302 (step 506 ), and transmits electricity The circuit 320 amplifies the chirp signal TX' generated by the chirp synthesizer 318 and transmits it through the transmit antenna 322 (step 508), wherein the chirp signal TX' includes N chirp sub-signals (as shown in FIG. 2A ). shown in each cycle from the start frequency of 77GHz to linearly increase to the end frequency of 81GHz).

Next, the receiving antenna 324 receives the reflected signal of the chirp signal TX' (step 510), the receiving circuit 326 can perform front-end signal amplification and front-end filtering on the reflected signal (step 512), and then the demodulation unit 328 converts the current chirp signal TX to 'Coupling with the reflected signal, and removing the RF signal from the demodulated signal through a low-pass filter to obtain an intermediate frequency signal IF' (step 514), the analog-to-digital converter 330 converts the analog-form intermediate frequency signal IF' into digital form (step 516).

Please also refer to FIG. 6. FIG. 6 is a schematic diagram of the operation of the arithmetic processing unit 332 according to the embodiment of the present invention. As shown in FIG. 6 , the arithmetic processing unit 332 firstly forms a matrix M1 with each part of the N chirp sub-signals corresponding to the chirp signal TX' in the intermediate frequency signal IF' in the digital form, and the horizontal part in the matrix M1 The points are sampled in one period Tc of the chirp sub-signal, and the vertical part is the different chirp sub-signals numbered 1~N (different from that shown in Figure 2A, the last intensity of each chirp sub-signal in each period Tc can be zero to avoid the reflection of the previous chirp sub-signal from affecting the demodulation of the subsequent chirp sub-signal).

Next, the arithmetic processing unit 332 performs a Range Fast Fourier Transform (Range FFT) on each column (transverse data) of the digital intermediate frequency signal IF' to obtain a matrix M2 (step 518 ), the horizontal part is in each line The distance frequency of the chirp sub-signal (the corresponding distance can be calculated according to Figure 2B and related formulas), and the vertical part is the different chirp sub-signals numbered 1~N. Among them, in the analyzed distance frequency distribution map, if there is a distance frequency exceeding the preset intensity, it means that there is an object (such as a human body designed with strong reflection intensity or the reflected signal of an activated reflector) at the corresponding distance of this distance frequency. can exceed the set strength). The intensity of these distance frequencies represents the intensity of the reflected signal of the object at the corresponding distance. The distance frequency can be converted into the corresponding distance according to the slope of the N chirp sub-signals of the chirp signal TX'. Each frequency peak represents the presence of an object. at that distance, i.e. at the shaded array in matrix M2. In other words, the arithmetic processing unit 332 can perform range fast Fourier transform on the intermediate frequency signal IF' to determine that at least one signal intensity of at least one range frequency in the intermediate frequency signal IF' is greater than a predetermined intensity and at least one subject and one subject to test The identity tag IDT2 is located at at least one distance corresponding to the at least one distance frequency (step 520).

Then, the arithmetic processing unit 332 performs vertical Doppler-FFT on the data at the frequency peak (ie, the shaded area) in the matrix M2 generated by the distance fast Fourier transform, to obtain an intermediate frequency signal IF 'A matrix M3 of phase change information, the phase change information represents the phase frequency information of the object at the relative distance (such as the physiological frequency information of respiration, heartbeat, the vibration frequency of the vibrator of the reflector, the rotation frequency of the motor or the frequency of the radar cross section. Modulation frequency and other identity frequencies, or information of object motion, such small displacements cannot be detected in the frequency domain of the IF signal, but the intensity changes caused by different chirp sub-signals, which can be transformed by Doppler Fast Fourier Transform Obtained), the horizontal part of the matrix M3 is the distance frequency (representing the distance) of each chirp sub-signal, and the vertical part represents the phase frequency distribution of the phase change (that is, the phase frequency of the phase change at a certain distance).

In this case, the control unit 312 can determine whether each phase frequency peak value of the vertical axis of the matrix M3 after Doppler fast Fourier transformation is the identity frequency of the identity tag IDT2 to be measured, and if so, it means that the corresponding distance is the identity to be measured. The distance position where the tag IDT2 is located. After finding the distance position where the identity tag IDT2 to be tested is located, the control unit 312 then determines whether there are other phase frequency peaks at the adjacent close distance (vertical axis). If yes, the control unit 312 analyzes whether physiological information (such as respiration, heartbeat frequency) is included. If there is, it means that the physiological information of the breathing and heartbeat is the information possessed by the test subject of the ID tag IDT2 to be tested. In this way, the control unit 312 can identify the object whose phase frequency (such as the vibration frequency, the rotation frequency of the motor, or the modulation frequency of the radar cross section) is a specific value according to the information processed by the FM CW radar 302 (ie, the identity to be detected). Label IDT2), and take the physiological information (respiration, heartbeat) of the adjacent objects as the physiological information of the subject to be tested in the IDT2 to be tested, and use the distance position as the distance position of the subject.

For example, the ID frequency of the ID tag IDT2 to be tested is generally set higher than the physiological frequencies such as respiration and heartbeat (for example, the vibration frequency is set to 1KHz, or the modulation frequency of the radar cross section is set to 5KHz) to reduce misjudgment during processing, control The unit 312 can first determine that the identity frequency of the identity tag IDT2 to be measured is at a specific frequency (distance) on the right side of the matrix M3 (such as the shadow on the upper right), and then judge that the phase frequency peak at the similar position below is the breath of the subject to be measured, Physiological frequencies such as heartbeat. In other words, the arithmetic processing unit 332 performs the Doppler fast Fourier transform on at least one component of the intermediate frequency signal IF' that corresponds to at least one distance frequency greater than the preset intensity (ie, the shadow of the matrix M2 ) Step 522), the control unit 312 determines that the identity frequency is at a specific distance and the intermediate frequency signal IF' is at a similar distance and at least one phase frequency with similar position information corresponds to the physiological information of the subject (step 524).

It is worth noting that, the main point of the above embodiment is that the tag reflector that can activate the specific identification tag has an identification frequency, so as to obtain the physiological information of the subject to be measured adjacent to the specific identification tag. Modifications or changes can be made based on common knowledge in the art, but are not limited thereto. For example, in the above embodiment, the current chirp signal TX' is coupled with the reflected signal to obtain the intermediate frequency signal IF', and then it is determined that the distance frequency in the intermediate frequency signal IF' whose signal strength is greater than a predetermined strength is the human body or has been activated. The distance of the reflector is determined, and then it is determined that at least one phase frequency with a similar distance to the identity frequency has similar position information and corresponds to the physiological information of the test subject. In other embodiments, in addition to having a similar distance, it is also necessary to consider having a similar direction before determining that there is similar position information.

Please refer to FIG. 7. FIG. 7 is a schematic diagram of determining the angle of arrival (AOA) of the reflected signal of the chirp signal TX' according to an embodiment of the present invention. As shown in FIG. 7, the receiving antenna 324 may include sub-receiving antennas 700, 702, and the sub-receiving antennas 700, 702 are separated by a distance d' for receiving the reflected signals RXH1-RXHn and the label reflected signal RXT, so as to determine a plurality of phases corresponds to the angle of arrival. In detail, since the distances between the object to be measured and the sub-receiving antennas 700 and 702 are different, the time when the reflected signal of the chirp signal TX' transmitted by the transmitting antenna 322 reaches the sub-receiving antennas 700 and 702 will also be different. There will also be a difference in the phase of the signal. This phase difference can be expressed as follows:

Among them, θ represents the arrival angle of the reflected signal. Therefore, the direction of the object to be measured can be detected by the phase difference of the reflected signals received by the sub-receiving antennas 700 and 702, and only when there is a similar distance and a similar direction can it be judged that it has similar position information .

For example, as shown in the lower part of Fig. 7, the phase frequencies obtained by the range fast Fourier transform and Doppler fast Fourier transform of the intermediate frequency signal IF' have the information of the respective angles of arrival. Therefore, when judging at least one phase frequency and After the identity frequency has a similar distance, it is also necessary to determine that at least one phase frequency and the identity frequency have a similar direction, in order to determine that at least one phase frequency and the identity frequency have similar position information and correspond to the physiological information of the subject (that is, the similar position information includes the similar distance. and similar directions). In addition, in the embodiment shown in FIG. 7, two sub-receiving antennas 700 and 702 are used to determine the direction of the object to be measured, but in other embodiments, more sub-receiving antennas can be expanded to increase resolution It can accurately detect the direction of the location of multiple objects.

Besides, in the above embodiment, the identity frequency is a vibration frequency of a vibrator, a rotation frequency of a motor, or a modulation frequency of a radar cross section in the activated tag reflector 310, but the tag reflector The implementation of the 310 is not limited, as long as the tag reflector 310 is activated so that the reflected signal has a phase change corresponding to the identity frequency. Briefly, the tag reflector 310 may include a vibrator capable of producing a specific vibration and capable of reflecting the chirp signal TX', or capable of backscattering in response to and modulating the chirp signal TX' (eg by modulating the frequency change the radar cross section).

In one embodiment of the tag reflector 310, in order to generate vibration, a speaker diaphragm can be used to give a specific vibration signal (eg, having a specific vibration frequency as an identity frequency), or a cell phone vibrator can be used. In addition, in order to effectively increase the reflected signal strength of the modulated chirp signal TX', the speaker diaphragm can be coated with a metal film, or the speaker diaphragm structure can be designed to be similar to a corner reflector (or a collection of miniature corner reflectors). body) to enhance the reflected signal strength of the modulated chirp signal TX'.

In detail, the corner reflector can be a right pyramid structure or a dihedral mirror. corner reflector), with this geometry, the incident signal can be reflected back and parallel to the incident signal, so it can have a better radar cross section. In addition, if the speaker diaphragm is only designed with a single corner reflector, it will have the problem of being too thick. Therefore, a collection of multiple miniaturized corner reflectors can be designed on the speaker diaphragm. By reducing the size, the overall structure can be made more compact. Thin and retains a similar radar cross section. In the case where the speaker diaphragm or the mobile phone vibrator has the structure of a corner reflector or a miniaturized corner reflector aggregate, when a selected vibration frequency (ie, identity frequency) is given to vibrate on the speaker diaphragm or the mobile phone vibrator, the The reflected signal has obvious changes corresponding to the identity frequency, so that the distance and the identity frequency can be analyzed. The above-mentioned embodiment mainly uses the speaker diaphragm or the mobile phone vibrator to vibrate at the vibration frequency, and has the corner reflector structure as the reflective surface. The characteristics of the other speakers are well known to those of ordinary knowledge in the art, and will not be repeated here for brevity. .

Furthermore, in another embodiment of the tag reflector 310, a motor can be used to control a metal reflector to rotate at a rotational frequency (ie, an identity frequency), so that the metal reflector is relative to the modulation chirp signal TX'. The reflection area (radar cross section) varies according to the rotational frequency.

Additionally, in another embodiment of the tag reflector 310, backscatter transponders of actively controlled frequency selective surfaces (FSS) may be used. The frequency selective surface consists of dipoles fitted with switched PIN diodes. The transponder controls the diode bias to modulate the change in the radar cross-section of the frequency selective surface to modulate the tag's backscatter response to the frequency modulated continuous wave radar 302 . Appropriately selected PIN diode and frequency selective surface resonator design can cover the sweep frequency of the chirp signal TX' of the FM CW radar 302. For example, the antenna length of the frequency selective surface is longer when the PIN diode is turned on, and the antenna length can be appropriately designed at this time to resonate with the chirp signal TX' and have a strong reflection signal. Therefore, the bias voltage of the diode can be controlled to adjust the frequency according to the frequency modulation. The radar cross-section of the frequency-selective surface is rate-modulated, so that the reflected signal has a change in intensity corresponding to the modulation frequency (identity frequency).

In addition, in another embodiment of the label reflector 310, an actively controlled product may be used The resonator of the bulk circuit. After the integrated circuit receives the linear frequency modulation signal TX' through the antenna, after the resonance signal is generated by the matching network and the resonator, the control signal determines whether to transmit the resonance signal as the reflection signal according to the modulation frequency, that is, according to the modulation frequency. The resonant signal generated by the variable frequency modulation resonator causes the reflected signal to have a change in intensity corresponding to the modulation frequency (identity frequency).

It is worth noting that, in the above embodiment, after the tag reflector 310 is activated to have the identity frequency, the tag reflected signal RXT may not only have a phase change corresponding to the identity frequency, but the tag reflected signal RXT may also have a phase change corresponding to the identity frequency and the chirp signal TX. ' frequency coupling, so that the frequency of the tag reflection signal RXT is the frequency of the corresponding chirp signal TX' plus or minus the identity frequency, so that the distance frequency observed by the identity tag IDT to be tested is the actual distance frequency plus minus the identity frequency. In this case, after the distance fast Fourier transform is performed, two distance frequencies corresponding to the identity frequency of the identity tag IDT to be tested can be found first, and the two distance frequencies can be added and averaged to obtain the actual distance frequency. The distance frequency is subtracted and then averaged to obtain the identity frequency.

In addition, in the above-mentioned embodiment, the identity tag is set next to the test subject to detect the physiological information of the test subject. However, in other embodiments, the test subject can also be a non-human object and other information of the test subject is detected. For example, the present invention can also be applied to detect the location of a specific object. Specifically, FM CW radar can detect the distance and speed of an object, but it does not know what the object is. After the identification tag is placed on an object (such as a car), when the car is moving (or stationary), the FMCW radar 302 can detect the distance and speed of the object and the detected distance and speed of the identification tag. It is the same (or similar) to the object, and it is determined that the object is a car with an identity tag.

In addition, the tag controller 308, the control unit 312 and the arithmetic processing unit 332 may be processors, such as a microprocessor or an application-specific integrated circuit (ASIC). The identification tag IDT and the FM CW radar identification device 32 may each include a storage unit. The storage unit can be any data storage device used to store a code, and read and execute the code through the processor to perform the above-mentioned related operations. The storage unit can be a subscriber identity module module, SIM), read-only memory (ROM), random-access memory (RAM), CD-ROMs (CD-ROMs), magnetic tapes (magnetic tapes), floppy disks, optical data storage devices, etc., but not limited thereto.

To sum up, the present invention can activate the tag reflector of the specific identification tag to have the identification frequency, so as to obtain the information of the subject to be measured adjacent to the specific identification tag. The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

50: Process

500~524: Steps

Claims (20)

A frequency modulated continuous wave (Frequency Modulated Continuous Wave, CW) radar system, comprising: at least one identity tag (identity tag), respectively disposed next to at least one to-be-tested; and a frequency modulated continuous wave radar identification device, comprising: an identity recognition control module for sending a control signal to control an identity tag to be tested in the at least one identity tag to be turned on, so that the identity tag to be tested generates a specific tag reflection signal corresponding to an identity frequency in response to a chirp signal ; and a frequency-modulated continuous wave radar for transmitting the chirp signal and receiving at least one reflected signal of the at least one subject and the specific label reflected signal in response to the chirp signal, to calculate and determine the specific label A specific reflected signal among the reflected signal and the at least one reflected signal corresponds to a near position information; wherein, the specific reflected signal corresponds to information of a test subject. The frequency-modulated continuous wave radar system of claim 1, wherein the identification tag to be tested is turned on to activate a corresponding reflector to have the identification frequency, and the identification frequency is one of a vibration frequency and a motor in the corresponding reflector Rotation frequency, or a modulation frequency. The FM continuous wave radar system of claim 1, wherein the chirp signal comprises a plurality of chirp sub-signals, and each of the plurality of chirp sub-signals linearly increases from a start frequency to a stop frequency in each cycle. The FM CW radar system of claim 1, wherein the FM CW radar demodulates and low-pass filters the current chirp signal, the at least one reflected signal and the specific tag reflected signal to generate an intermediate frequency Signal. The frequency-modulated continuous wave radar system of claim 1, wherein the frequency-modulated continuous wave radar performs a range fast Fourier transform on an intermediate frequency signal (Range Fast Fourier Transform, Range FFT), to determine that at least one signal strength of at least one range frequency in the IF signal is greater than a predetermined intensity and the at least one subject and the ID tag to be tested are located at at least one distance corresponding to the at least one range frequency place. The FM CW radar system as claimed in claim 5, wherein the FM CW radar performs at least one component of the intermediate frequency signal corresponding to the at least one range frequency greater than the preset intensity in the intermediate frequency signal subjected to the range fast Fourier transform. Doppler fast Fourier transform (Doppler-FFT) to determine that the identity frequency is at a close distance of the close position information and at least one phase frequency of the intermediate frequency signal at the close distance corresponds to the test subject information . The FM CW radar system as claimed in claim 1, wherein the FM CW radar comprises a plurality of sub-receiving antennas for receiving the at least one reflected signal and the reflected signal of the specific tag to determine a plurality of corresponding angles of arrival (Angle of Arrival, AOA), and the proximity location information includes a proximity distance and a proximity direction. The FM continuous wave radar system according to claim 2, wherein a speaker diaphragm or a mobile phone vibrator in the corresponding reflector vibrates at the vibration frequency, and the speaker diaphragm or the mobile phone vibrator has a corner reflector or A structure of a miniaturized corner reflector assembly. The FM continuous wave radar system of claim 2, wherein the motor controls a metal reflector to rotate at a rotational frequency, so that the reflection area of the metal reflector relative to the modulated chirp signal changes according to the rotational frequency. The frequency modulated continuous wave radar system of claim 2, wherein a Radar Cross-Section (RCS) of a frequency selective surface in the corresponding reflector is modulated according to the modulation frequency, or the frequency is modulated according to the frequency modulation A resonant signal generated by a resonator in the corresponding reflector is rate modulated. An identity and information detection method for a frequency-modulated continuous wave radar system, comprising: respectively setting at least one identity tag beside at least one to-be-tested; Sending a control signal to control an identity tag to be tested in the at least one identity tag to be turned on; an FM continuous wave radar transmits a chirp signal; the identity tag to be tested generates a specific tag reflection corresponding to an identity frequency in response to the chirp signal signal; and the FM continuous wave radar receives at least one reflected signal of the at least one subject and the specific label reflected signal in response to the chirp signal, to calculate and determine the specific label reflected signal and the at least one reflected signal in the at least one reflected signal A specific reflected signal corresponds to a similar position information; wherein, the specific reflected signal corresponds to a test subject information. The identity and information detection method of claim 11, further comprising: turning on the identity tag to be tested to activate a corresponding reflector to have the identity frequency, the identity frequency being a vibration frequency in the corresponding reflector, A rotational frequency of a motor, or a modulation frequency. The identity and information detection method of claim 11, wherein the chirp signal comprises a plurality of chirp sub-signals, and each of the plurality of chirp sub-signals linearly increases from a start frequency to an end frequency in each cycle . The identity and information detection method of claim 11, wherein the FM CW radar demodulates and low-pass filters the current chirp signal, the at least one reflected signal, and the specific tag reflected signal to generate an intermediate frequency signal. The identity and information detection method according to claim 11, wherein the FM continuous wave radar performs a range fast Fourier transform (Range Fast Fourier Transform, Range FFT) on an intermediate frequency signal to determine at least one of the intermediate frequency signals. At least one signal strength of the distance frequency is greater than a predetermined strength, and the at least one subject and the identity tag to be tested are located at at least one distance corresponding to the at least one distance frequency. The identity and information detection method as claimed in claim 15, wherein the FM continuous wave radar performs the range fast Fourier transform of the intermediate frequency signal corresponding to the greater than the preset intensity Doppler fast Fourier transform (Doppler-FFT) is performed on at least one component of at least one distance frequency, so as to determine that the identity frequency is located in a close distance of one of the close position information and the intermediate frequency of the intermediate frequency signal is located in at least one of the close distances. The phase frequency corresponds to the subject information. The identity and information detection method as claimed in claim 11, wherein the FM continuous wave radar comprises a plurality of sub-receiving antennas for receiving the at least one reflected signal and the specific tag reflected signal to determine a plurality of corresponding arrival angles ( Angle of Arrival, AOA), and the proximity position information includes a proximity distance and a proximity direction. The identity and information detection method as claimed in claim 12, wherein a speaker diaphragm or a mobile phone vibrator in the corresponding reflector vibrates at the vibration frequency, and the speaker diaphragm or the mobile phone vibrator has a corner reflector Or the structure of a miniaturized corner reflector assembly. The identity and information detection method of claim 12, wherein the motor controls a metal reflector to rotate at a rotational frequency, so that the reflection area of the metal reflector relative to the modulated chirp signal changes according to the rotational frequency. The identity and information detection method of claim 12, wherein a Radar Cross-Section (RCS) of a frequency selective surface in the corresponding reflector is modulated according to the modulation frequency, or according to the modulation frequency A resonant signal generated by a resonator in the corresponding reflector is modulated by variable frequency.

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