TW202238166A - 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 turned 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 Identification and Information Detection Method

The present invention refers to a frequency-modulated continuous wave radar system and its identity and information detection method, especially to a tag reflector that can activate a specific ID tag with an ID frequency, so as to obtain the desired measurement of the target adjacent to the specific ID tag FM continuous wave radar system for information and its identification and information detection method.

In recent years, vital sign detection technology has developed rapidly (such as infrared body temperature measurement, blood sugar concentration detection, blood oxygen concentration detection), which also includes non-personal use of vital sign detection. For example, the non-contact heartbeat and breathing frequency detection device can transmit a radio frequency (RF) signal to the subject and receive the corresponding reflected signal. and body displacement caused by breathing) to produce modulation. After receiving, demodulating, filtering and amplifying the reflected signal, the algorithm inside the processor can calculate the heartbeat and breathing rate of the subject.

However, although the conventional continuous wave (CW) radar technology can remotely measure the physiological information such as the respiration and heartbeat of the subject, it is difficult to correctly detect the physiological information such as the respiration and heartbeat of the specified subject in a group of people, and 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 known technology.

Therefore, the main purpose of the present invention is to provide a frequency-modulated continuous wave radar system that can activate the tag reflector of a specific ID tag with an ID frequency to obtain the information of the subject to be measured adjacent to the specific ID tag and its ID and ID. Information detection method.

The invention discloses a frequency modulation continuous wave radar system, which includes at least one identity tag, which is respectively arranged beside at least one person to be tested; and a frequency modulation continuous wave radar identification device, which includes an identification control module, which is used to send a control The signal controls an identity tag to be tested in the at least one identity tag to turn on, so that the specific identity tag generates a specific tag reflection signal corresponding to an identity frequency in response to a chirp frequency modulation signal; and a frequency modulation continuous wave radar is used to transmit the linear frequency modulation signal. Frequency modulation signal, and receiving at least one reflection signal of the at least one subject to be tested and the specific label reflection signal in response to the linear frequency modulation signal, so as to calculate and judge a specific reflection signal in the specific label reflection signal and the at least one reflection signal Corresponding to a similar position information; wherein, the specific reflection signal corresponds to a subject information.

The present invention also discloses an identity and information detection method used in a frequency modulation continuous wave radar system, including setting at least one identity tag next to at least one person to be tested; sending a control signal to control one of the at least one identity tag The identity detection tag is turned on; a FM continuous wave 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 continuous wave radar receives a response to the chirp signal The at least one reflection signal of the at least one object to be tested and the specific label reflection signal of the signal are used to calculate and judge that the specific label reflection signal and the at least one reflection signal correspond to a similar position information; wherein, the The specific reflection signal corresponds to a subject's information.

Please refer to FIG. 1 , which is a schematic diagram of a frequency modulated continuous wave (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 continuous signals of the same frequency, while the FM continuous wave radar 10 transmits modulated frequency signals. To put it simply, the FM CW radar 10 includes a chirp synthesizer (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 encounters an object (such as a subject to be tested), a reflected signal RX is generated, and the reflected signal RX is received by a receiving antenna 104, and then coupled by a mixer (Mixer) 112 at this time, the chirp signal TX and the receiving antenna 104 The received reflection signal RX, the coupled output signal passes through a low pass filter (Low Pass Filter) or band pass filter (Band Pass Filter) 106 to filter out high frequency signals (such as chirp signal TX and reflection signal RX) , to generate an intermediate frequency signal IF, which is converted into a digital signal by an analog to digital converter (Analog to Digital Converter, ADC) 108, and then processed by a processor 110 to obtain distance, direction and physiological information (Vital Sign).

Please refer to Figure 2A and Figure 2B. Figure 2A is a schematic diagram of the chirp signal TX versus time, and Figure 2B is a schematic diagram of the chirp signal TX, reflected signal RX, and intermediate frequency signal IF. In detail, as shown in the lower part of Figure 2A, the frequency of the chirp signal TX increases linearly with time with a modulation slope S, so as shown in the upper part of Figure 2A, in the time domain, the frequency of the chirp signal TX The period of the frequency gradually becomes narrower; as shown in the upper part of Figure 2B, the reflection signal RX starts to be received at a time 𝜏 after the chirp signal TX is transmitted, so as shown in the lower part of Figure 2B, the signal with a frequency S𝜏 can be obtained The relationship between the intermediate frequency signal IF can be expressed as follows:

為訊號傳播速度（光速），其餘振幅、角速度、相位、頻率、波長之表示為本領域所熟知，於此不再贅述。由上述方程式可知，中頻信號IF之頻率

之資訊隱含了待測者之距離d，中頻信號IF之相位

隱含了待測者呼吸、心跳等生理資訊（因呼吸、心跳造成的身體位移約1-2 mm，僅在一個毫米波波長12.5 mm周期中不影響頻率），因此處理器110可透過演算求得待測者之距離、方向及呼吸、心跳。 Wherein, d is the distance between the person to be measured and the frequency modulation continuous wave radar 10,

is the signal propagation speed (speed of light), and the representations of the other amplitudes, angular velocities, phases, frequencies, and wavelengths are well known in the art and will not be repeated here. It can be known from the above equation that the frequency of the intermediate frequency signal IF

The information implies the distance d of the object to be measured, the phase of the intermediate frequency signal IF

Physiological information such as respiration and heartbeat of the subject is implied (the body displacement caused by respiration and heartbeat is about 1-2 mm, and the frequency is not affected only in one millimeter wave wavelength of 12.5 mm period), so the processor 110 can calculate the Get the distance, direction, breathing and heartbeat of the subject to be tested.

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

To put it simply, the operation of the FM CW radar 302 is similar to the operation of the FM CW radar 10 for obtaining the distance, direction, respiration, and heartbeat of the subject to be measured. The main differences between the FM CW radar system 30 and the FM CW radar 10 That is, the frequency modulation continuous wave radar system 30 sets the identity tag IDT that can be opened or closed (after the label reflector 310 can make a tag reflection signal RXT have a phase change corresponding to an identity frequency in a specific vibration and other ways) to be tested Then the identity recognition control module 300 sends a control signal CON to control the identity tag IDT to turn on through wireless communication. After the FM continuous wave radar 302 sends a chirp signal TX', it can receive one of the reflected signals RXH and The tag reflection signal RXT of the ID tag IDT is processed to obtain the distance, direction and physiological information (breathing, heartbeat) of the subject to be tested, as well as the distance, direction and identity frequency of the ID tag IDT. In this case, since the identity tag that has not been opened does not reflect the tag reflection signal with identity information (such as identity frequency), the frequency modulation continuous wave radar 302 can calculate the physiological information of the testee and the identity tag IDT at the same distance and direction. Combined, it is possible to know which subject's physiological information the measured breathing and heartbeat physiological information belongs to. In this way, the present invention can activate the tag reflector of the specific ID tag to have the ID frequency, so as to obtain the physiological information of the subject to be measured adjacent to the specific ID tag.

For example, please refer to FIG. 4 , which is a schematic diagram of the operation of a frequency-modulated continuous wave radar system 40 according to an embodiment of the present invention. The frequency modulation continuous wave radar system 40 is roughly the same as the frequency modulation continuous wave radar system 30, so components and signals with similar functions are represented by the same symbols for simplicity. The main difference between the frequency modulation continuous wave radar system 40 and the frequency modulation continuous wave radar system 30 is that the frequency modulation The continuous wave radar system 40 includes different identity tags IDT1-IDTn (which have the same structure as the identity tag IDT) and are set beside different subjects (such as hands), so the identity recognition control module 300 sends the control signal CON through wireless communication. In the case where one identity tag IDT2 to be tested is 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', the person to be tested who responds to the chirp signal TX' can be received One of the reflected signals RXH1~RXHn and the tag reflected signal RXT2 of the identity tag IDT2 corresponding to the identity frequency are processed (the tag reflection signals of the other identity tags indicated by the dotted line do not correspond to the identity frequency and cannot be detected), so the frequency modulation is continuous The wave radar 302 can calculate and judge that the reflection signal RXH2 and the tag reflection signal RXT2 correspond to similar position information (distance, direction), and can obtain the physiological information of the subject corresponding to the respiration and heartbeat of the subject to be measured from the reflection signal RXH2 .

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

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

When the tag reflector 310 is activated, when the identity tag IDT receives the chirp signal TX', it can generate a tag reflection signal RXT corresponding to the frequency of the ID 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 reflected signals such as touching the human body, the identity tag IDT, and stationary or moving objects in the environment), and then the receiving circuit 326 can respond to the 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 under test. If the direction is to be identified, the design of multiple transmitting or receiving antennas must be considered.

In this case, although the main 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 (the human body or metal has a strong reflection intensity), and the phase change of the reflection signal RXH generated by coupling the chest displacement caused by the breathing and heartbeat of the body corresponds to a specific physiological frequency, and the tag reflection signal RXT corresponds to a specific identity frequency ( Such as the vibration frequency of the vibrator in the label reflector 310, the rotation frequency of a motor or the modulation frequency of the Radar Cross-Section (RCS), etc.), and the reflected signals at different distances have different modulation frequencies rate difference.

In addition, the demodulation unit 328 can demodulate (such as 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 passed through a low-pass filter to remove radio frequency signals (such as chirp signal TX', reflected signal RXH and tag reflected signal RXT) to obtain an intermediate frequency signal IF'. Next, the analog-to-digital converter 330 converts the analog IF signal IF' into a digital form, which is convenient for the operation processing unit 332 to process. Then, the calculation processing unit 332 uses various digital processing algorithms to remove noise, high-frequency signals and inappropriate respiratory harmonics to calculate the distance, direction, and identity information (such as identity frequency) of the identity tag IDT to be detected. , human body distance, breathing, and heartbeat wait for the physiological information of the tester. Finally, the control unit 312 compares the distance and direction to find the identity information of the identity tag IDT and the physiological information of the tester such as human breathing and heartbeat at the same (close) distance (and/or direction), so as to distinguish the physiological information ( Breathing, heartbeat) belong to the subject corresponding to the identity tag IDT (or the comparison is performed by the computing processing unit 332, and the two can also be integrated into a single processor).

The operations of the above-mentioned FM CW radar systems 30 and 40 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 frequency modulation continuous wave radar identification device 32 can search for the identity tags IDT1-IDTn through the wireless communication unit 314, and control the identity tag IDT2 to be turned on (step 502), so that the identity tag IDT2 to be tested is turned on to start a The corresponding label reflector has an identity frequency (step 504), wherein the identity frequency is a vibration frequency of a vibrator (vibrator) in the corresponding label reflector, a rotational frequency of a motor or a radar cross section (Radar Cross- Section, RCS) one of the modulation frequency. Next, the FM CW radar identification device 32 activates the FM CW radar 302 (step 506), the transmitting circuit 320 amplifies the chirp signal TX' generated by the chirp synthesizer 318 and transmits it through the transmitting antenna 322 (step 508), Wherein, the chirp signal TX' includes N chirp sub-signals (which can be linearly increased from the start frequency of 77 GHz to the stop frequency of 81 GHz in each cycle as shown in FIG. 2A ).

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 'Coupling with the reflected signal, and removing the radio frequency signal from the demodulated signal through a low-pass filter to obtain the intermediate frequency signal IF' (step 514), the analog-to-digital converter 330 converts the analog intermediate frequency signal IF' into in digital form (step 516).

Please also refer to FIG. 6 , which is a schematic diagram of the operation of the operation processing unit 332 according to an embodiment of the present invention. As shown in Fig. 6, the arithmetic processing unit 332 forms a matrix M1 with the parts of the N chirp sub-signals corresponding to the chirp signal TX' in the intermediate frequency signal IF' in digital form, and the horizontal part of the matrix M1 It is the point sampled in one cycle Tc of the chirp sub-signal, and the vertical part is different chirp sub-signals numbered 1 to N (different from that shown in Figure 2A, the final strength of each chirp sub-signal in each cycle Tc can be zero to avoid the reflection signal of the previous chirp sub-signal affecting the demodulation of the next chirp sub-signal).

Next, the arithmetic processing unit 332 performs Range Fast Fourier Transform (Range FFT) on each column (horizontal data) of the intermediate frequency signal IF' in digital form to obtain a matrix M2 (step 518), and the horizontal part is 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 at the distance corresponding to this distance frequency (such as the reflection signal of a human body with a strong reflection intensity or an activated reflector) can exceed the set strength). The intensity of these distance frequencies indicates the intensity of the reflected signal of the object corresponding to the 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', and each frequency peak represents the presence of an object. At that distance, the shadow array in matrix M2. In other words, the arithmetic processing unit 332 can perform distance fast Fourier transform on the intermediate frequency signal IF' to determine that at least one signal strength of at least one distance frequency in the intermediate frequency signal IF' is greater than a preset strength and at least one test object and the test object The identity tag IDT2 is located at least one distance corresponding to the at least one distance frequency (step 520 ).

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

In this case, the control unit 312 can judge whether each phase frequency peak of the vertical axis of the matrix M3 after the Doppler fast Fourier transform is the identity frequency of the identity tag IDT2 to be tested, and if so, it means that the corresponding distance is the identity frequency of the identity to be tested. The distance position where the tag IDT2 is located. After finding the distance position of the identity tag IDT2 to be tested, the control unit 312 judges whether there are other phase frequency peaks at adjacent distances (vertical axis). If so, the control unit 312 analyzes whether it contains physiological information (such as the frequency of breathing and heartbeat). If yes, it means that the physiological information of breathing and heartbeat is the information of the subject of the identity tag IDT2 to be tested. In this way, the control unit 312 can identify objects 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 (that is, the identity to be detected) based on the information processed by the frequency modulation continuous wave radar 302 Tag IDT2), and use the physiological information (breathing, heartbeat) of the adjacent object as the physiological information of the subject of the identity tag IDT2 to be tested, and use the distance position as the distance position of the subject.

For example, the identity frequency of the identity tag IDT2 to be tested is generally set higher than the physiological frequency such as breathing and heartbeat (such as the vibration frequency is set to 1KHz, or the modulation frequency of the radar cross section is 5KHz) to reduce misjudgment during processing and control Unit 312 can first determine that the identity frequency of the identity tag IDT2 to be tested is on a specific frequency (distance) on the right side of the matrix M3 (such as the upper right shadow), and then determine that the phase frequency peak value at a similar position below is the breath of the person to be tested, Physiological frequency such as heartbeat. In other words, the arithmetic processing unit 332 performs Doppler fast Fourier transform (FFT) on at least one component of the intermediate frequency signal IF' corresponding to at least one range frequency greater than a preset intensity (ie, the shadow of the matrix M2) during the range FFT ( Step 522 ), so that 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 should be noted that the main feature of the above embodiment is that the tag reflector of the specific ID tag can be activated to have an ID frequency, so as to obtain the physiological information of the subject to be measured adjacent to the specific ID tag. Modifications or changes can be made based on common knowledge in the art, and 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 judged that the distance frequency in the intermediate frequency signal IF' whose signal strength is greater than a preset strength is the human body or has been activated. Then determine 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 subject. In other embodiments, in addition to having a close distance, it is also necessary to consider having a close direction to determine that there is close 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 and 702, and the sub-receiving antennas 700 and 702 are separated by a distance d' to receive reflected signals RXH1 to RXHn and tag reflected signals RXT to determine a plurality of phases. corresponding to the angle of arrival. In detail, since the distance between the object to be measured and the sub-receiving antennas 700 and 702 is different, the time for the reflected signal of the chirp signal TX' transmitted by the transmitting antenna 322 to reach the sub-receiving antennas 700 and 702 will also be different. There will also be a difference in the phase of the signal, which can be expressed as follows:

表示反射信號之到達角度，因此可藉由子接收天線700、702所接收反射信號之相位差，偵測待測物體之方向，並於具有相近距離及相近方向時才判斷具有相近位置資訊。 in,

Indicates the angle of arrival of the reflected signal. Therefore, the phase difference of the reflected signal received by the sub-receiving antennas 700 and 702 can be used to detect the direction of the object to be measured, and it can be judged that it has similar position information when it has a similar distance and a similar direction.

For example, as shown in Figure 7, the phase frequency obtained by the range fast Fourier transform and the Doppler fast Fourier transform of the intermediate frequency signal IF' has the information of the respective angles of arrival, so when judging at least one phase frequency and After the identity frequency has a similar distance, it is also necessary to judge that at least one phase frequency and the identity frequency have a similar direction, and then it can be judged 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 a similar distance and similar directions). In addition, in the embodiment shown in Figure 7, two sub-receiving antennas 700, 702 are used to determine the direction of the object to be measured, but in other embodiments, it can also be expanded to more sub-receiving antennas to increase the resolution. Accurately detect the direction of the location of multiple objects.

In addition, in the above-mentioned embodiments, the identity frequency is the vibration frequency of a vibrator, the rotation frequency of a motor, or the modulation frequency of a radar cross section in the activated tag reflector 310, but the tag reflector The implementation of 310 is not limited, as long as the tag reflector 310 can cause the reflected signal to have a phase change corresponding to the frequency of the ID after activation. In simple terms, the tag reflector 310 may include a vibrator that can generate specific vibrations and reflect the chirp signal TX', or can backscatter (backscatter) to respond to and modulate the chirp signal TX' (such as by modulating the frequency changing radar cross section).

In an embodiment of the label reflector 310, in order to generate vibration, a speaker diaphragm can be used to give a specific vibration signal (such as having a specific vibration frequency as the identity frequency), or a mobile 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 plated with a metal film, or the structure of the speaker diaphragm can be designed as 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-angle pyramid structure or a dihedral corner reflector (dihedral corner reflector). With this geometric structure, the incident signal can be reflected back and parallel to the incident signal, so it can have a better radar cross-angle reflector. 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, and the overall structure can be made more compact by reducing the size. Thin and retain a similar radar cross-section. In the case that the speaker diaphragm or mobile phone vibrator has a structure of a corner reflector or a miniaturized corner reflector assembly, when a selected vibration frequency (ie, identity frequency) is given to vibrate on the speaker diaphragm or mobile phone vibrator, the The reflected signal has a relatively obvious change corresponding to the identity frequency, so as to analyze the distance and identity frequency. The above-mentioned embodiment mainly uses the speaker diaphragm or the mobile phone vibrator to vibrate at the vibration frequency, and has a corner reflector structure as the reflecting surface. The characteristics of the other speakers are well known to those skilled in the art, and will not be repeated here for the sake of brevity. .

Moreover, in another embodiment of the label reflector 310, a motor can be used to control a metal reflector to rotate at a rotation frequency (ie, the identity frequency), so that the metal reflector is relative to the frequency of the modulated chirp signal TX'. The reflective area (radar cross section) changes according to this rotation frequency.

Furthermore, in another embodiment of the tag reflector 310, actively controlled frequency selective surfaces (FSS) backscatter transponders may be used. The frequency selective surface consists of a dipole fitted with a switching PIN type diode. The transponder controls the diode bias to modulate the change in radar cross-section of the frequency selective surface to modulate the tag's backscatter response to the FM CW radar 302 . Proper selection of the PIN diode and design of the frequency selective surface resonator can cover the scanning 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. At this time, the antenna length can be properly designed 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. The radar cross-section of the rate-modulated frequency selects the surface, so that the reflected signal has a change in strength corresponding to the modulated frequency (identity frequency).

Additionally, in another embodiment of the tag reflector 310, an actively controlled IC resonator may be used. After the integrated circuit receives the chirp signal TX' through the antenna, the resonance signal is generated by the matching network and the resonator, and then the control signal determines whether to transmit the resonance signal as the reflected signal according to the modulation frequency, that is, according to the modulation frequency The resonance signal generated by the frequency modulation resonator makes the reflection signal have a change in strength corresponding to the modulation frequency (identity frequency).

It is worth noting that, in the above embodiment, after the tag reflector 310 starts to have the ID frequency, the tag reflected signal RXT may not only have a phase change corresponding to the ID frequency, but the tag reflected signal RXT may also have a phase change corresponding to the ID frequency and the chirp signal TX. The frequency coupling of 'makes the frequency of the tag reflection signal RXT be 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 or minus the identity frequency. In this case, after performing distance fast Fourier transform, 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 are added and then averaged to obtain the actual distance frequency, and the two The distance frequency is subtracted and then averaged to obtain the identity frequency.

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

In addition, the tag controller 308 , the control unit 312 and the operation processing unit 332 can be processors, such as a microprocessor or an application-specific integrated circuit (ASIC). The identity tag IDT and the FMCW radar identification device 32 may respectively include a storage unit. The storage unit can be any data storage device, used to store a program code, and read and execute the program code through the processor to perform the above-mentioned related operations. The storage unit can be a subscriber identity module (SIM), a read-only memory (ROM), a random-access memory (RAM), a CD-ROM ( CD-ROMs), magnetic tapes, floppy disks, optical data storage devices, etc., without limitation.

To sum up, the present invention can activate the tag reflector of the specific ID tag to have the ID frequency, so as to obtain the information of the subject to be measured adjacent to the specific ID 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.

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 converter 110: Processor 112: Mixer 30, 40: FM continuous wave radar system 32: Frequency modulation continuous wave radar identification device 300: Identification control module 302: FM continuous wave 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: Transmitting circuit 322: Transmitting antenna 324: Receiving antenna 326: Receiving 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: ID tags RXH, RXH1~RXHn: reflected signal RXT, RXT1~RXTn: tag reflection signal CON: control signal M1~M3: Matrix Tc: cycle

Figure 1 is a schematic diagram of a frequency modulated 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 intermediate frequency signal. Fig. 3 is a schematic diagram of a frequency-modulated continuous wave radar system according to an embodiment of the present invention. Fig. 4 is a schematic diagram of the operation of another frequency modulation continuous wave radar system according to the 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 judging the angle of arrival of the reflected signal of the chirp signal according to the embodiment of the present invention.

50: Process

500~524: steps

Claims (20)

A frequency modulated continuous wave (Frequency Modulated Continuous Wave, CW) radar system, including: at least one identity tag (identity tag), which is set next to at least one subject; and A frequency modulation continuous wave radar identification device, including: An identity identification control module, used to send a control signal to control the opening of an identity tag to be tested in the at least one identity tag, so that the specific identity tag generates a specific tag reflection signal corresponding to an identity frequency in response to a chirp signal; as well as A frequency-modulated continuous wave radar, used to transmit the chirp signal, and receive at least one reflection signal of the at least one object to be tested and the specific tag reflection signal in response to the chirp signal, to calculate and judge the specific tag reflection signal and a specific reflected signal in the at least one reflected signal corresponds to a close location information; Wherein, the specific reflection signal corresponds to a subject information. The frequency-modulated continuous wave radar system as described in claim 1, wherein the identity tag to be tested is opened to activate a corresponding reflector having the identity frequency, and the identity frequency is one of a vibration frequency and a motor in the corresponding reflector rotation frequency, or a modulation frequency. The frequency-modulated continuous wave radar system according to claim 1, wherein the chirp signal includes 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 frequency modulation continuous wave radar system as described in claim 1, wherein the frequency modulation continuous wave 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 modulation continuous wave radar system as described in claim 1, wherein the frequency modulation continuous wave radar performs a range fast Fourier transform (Range Fast Fourier Transform, Range FFT) on the intermediate frequency signal to determine at least one range in the intermediate frequency signal At least one signal strength of the frequency is greater than a preset strength, and the at least one test subject and the test identity tag are located at least one distance corresponding to the at least one distance frequency. The frequency modulated continuous wave radar system as described in claim 5, wherein the frequency modulated continuous wave 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 range fast Fourier transform Doppler fast Fourier transform (Doppler-FFT), to determine that the identity frequency is at a close distance of the close location information and at least one phase frequency of the intermediate frequency signal at the close distance corresponds to the subject information . The frequency modulation continuous wave radar system as described in claim 1, wherein the frequency modulation continuous wave radar includes 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 angles of arrival (Angle of Arrival, AOA), and the approximate location information includes an approximate distance and an approximate direction. The frequency modulation continuous wave radar system as described in claim 2, wherein a loudspeaker diaphragm or a mobile phone vibrator in the corresponding reflector vibrate at the vibration frequency, and the loudspeaker diaphragm or the mobile phone vibrator has a corner reflector or A structure of miniaturized corner reflector assembly. The frequency-modulated continuous wave radar system according to claim 2, wherein the motor controls a metal reflector to rotate at a rotation frequency, so that the reflection area of the metal reflector relative to the modulated chirp signal changes according to the rotation frequency. The frequency modulation continuous wave radar system as described in claim 2, wherein a radar cross-section (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 rate modulated. An identity and information detection method for a frequency modulation continuous wave radar system, comprising: Respectively setting at least one identity tag (identity tag) next to at least one subject to be tested; sending a control signal to control the opening of an identity tag to be tested in the at least one identity tag; a frequency modulated continuous wave radar transmitting a linear frequency modulated signal; the ID-specific tag generates a tag-specific reflection signal corresponding to an ID frequency in response to the chirp signal; and The frequency modulated continuous wave radar receives at least one reflection signal of the at least one subject to be detected and the specific tag reflection signal in response to the chirp signal, to calculate and determine a specific reflection signal in the specific tag reflection signal and the at least one reflection signal The signal corresponds to a similar location information; Wherein, the specific reflection signal corresponds to a subject information. The identity and information detection method described in claim 11 further includes: Opening the identity tag to be tested activates a corresponding reflector to have the identity frequency, and the identity frequency is a vibration frequency in the corresponding reflector, a rotation frequency of a motor, or a modulation frequency. The identity and information detection method as described in 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 a stop frequency in each cycle . The identity and information detection method as described in claim 11, wherein the FM continuous wave radar demodulates and low-pass filters the current chirp signal, the at least one reflected signal and the specific tag reflected signal to generate a middle frequency signal. The identity and information detection method as described in claim 11, wherein the FM continuous wave radar performs a Range Fast Fourier Transform (Range FFT) on the 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 preset strength, and the at least one test subject and the test identity tag are located at least one distance corresponding to the at least one distance frequency. The identity and information detection method as described in claim 15, wherein the frequency-modulated continuous wave radar performs at least one component of the intermediate frequency signal corresponding to the at least one range frequency greater than the preset intensity for performing the range fast Fourier transform Doppler fast Fourier transform (Doppler-FFT) is performed to determine that the identity frequency is at a close distance of the close location information and at least one phase frequency of the intermediate frequency signal at the close distance corresponds to the subject Information. The identity and information detection method as described in claim 11, wherein the FM continuous wave radar includes 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 angles of arrival ( Angle of Arrival, AOA), and the approximate location information includes an approximate distance and an approximate direction. The identity and information detection method as described 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 as described in claim 12, wherein the motor controls a metal reflector to rotate at a rotation frequency, so that the reflective area of the metal reflector relative to the modulated chirp signal changes according to the rotation frequency. The identity and information detection method as described in claim 12, wherein a radar cross-section (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 A resonant signal generated by a resonator in the corresponding reflector is modulated by variable frequency.

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