A vital sign and consciousness monitoring system based on active and passive radar

Abstract

The present invention discloses a vital sign and consciousness monitoring system based on active and passive radar. Based on existing millimeter-wave radar for vital sign monitoring, this system uses a low-sidelobe, high-gain, high-sensitivity dual-frequency receiving antenna to receive millimeter-wave echo signals and brain wave signals, namely, Ka-band and brain wave band signals. Simultaneously, an extremely low frequency (0-20 MHz) high-sensitivity receiver is added to the high-sensitivity receiver module to receive and condition the brain wave radiation signals. The signal processing module then samples and analyzes the processed data. The analyzed data is compared with the processed data of normal individuals stored in the data storage module. When the difference exceeds a threshold, it indicates that the patient's vital signs or consciousness are abnormal, and an early warning signal is issued. The present invention is a non-contact monitoring system based on active and passive radar. It accurately collects vital sign and brain wave signals, enabling real-time, continuous, and dynamic monitoring of the patient's vital signs and consciousness, thereby facilitating the rapid recovery of patients under good rest conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of vital signs and consciousness status monitoring, and more specifically, relates to a vital signs and consciousness status monitoring system based on active and passive radars. Background Art

[0002] Monitoring the vital signs and consciousness of hospitalized patients and elderly patients with chronic diseases plays a crucial role in clinical observation. Changes in these signs and consciousness are closely linked to the progression of their condition. Failure to promptly detect these changes can delay emergency care, resulting in irreversible consequences and a serious impact on the patient's prognosis.

[0003] In particular, real-time preventative monitoring of postoperative consciousness in patients at high risk for delirium can enable earlier interventional treatment and reduce the impact of delirium-related sequelae. Furthermore, for elderly patients with chronic diseases that develop rapidly and progress rapidly, and who face limitations in real-time, daily health monitoring using specialized equipment, early detection of disease signs, rapid response, and treatment strategies to reduce morbidity and mortality are also of profound significance.

[0004] Therefore, the current key research direction is to achieve contactless, sustainable, and fully dynamic condition monitoring for hospitalized patients and patients with chronic geriatric diseases, ensure timely and accurate monitoring of patients' condition changes, and improve the effect of patient condition monitoring.

[0005] Existing monitoring of vital signs and consciousness status mainly relies on traditional clinical observation by medical staff and instrument monitoring of key patients.

[0006] In addition to traditional clinical observation, monitoring of a patient's heart and respiratory status typically involves using an ECG monitor in conjunction with a blood oxygen monitoring kit to measure the patient's heart rhythmic electrical activity and oxygen saturation, depending on the patient's condition. During use, medical staff place electrodes on the patient's wrist, fingers, and other areas of the ECG monitor. Recording parameters such as heart rhythmic electrical activity and oxygen saturation reflect the patient's vital signs and functional status.

[0007] Currently, monitoring of a patient's state of consciousness is primarily done using instruments based on their condition, such as electroencephalogram (EEG) monitoring and bispectral index (BIS) monitoring. Electrodes are placed on the patient's scalp using an EEG device, which records the rhythmic electrical activity of brain cell groups, reflecting the patient's state of consciousness.

[0008] Traditional clinical monitoring has obvious limitations and challenges:

[0009] Chronic geriatric diseases often develop quickly and progress rapidly, so real-time monitoring of their condition is crucial for early warning and treatment. However, using monitoring equipment to monitor chronic geriatric patients is unrealistic from both a cost and convenience perspective.

[0010] To ensure real-time, preventative monitoring of postoperative consciousness in patients at risk of delirium, patients are categorized by their condition into different nursing levels, with varying patrol frequencies (special-level nursing requires close observation; first-level nursing has hourly patrols; second-level nursing has two-hourly patrols; and third-level nursing has three-hourly patrols). Even with special-level nursing, real-time dynamic assessment and monitoring of patients at the bedside cannot be guaranteed. There are gaps in observation, making it difficult to detect changes in the patient's condition in a timely manner. However, using EEG monitoring equipment for only preventative monitoring of patients at risk of delirium in real time not only consumes precious medical resources, but also places a physical burden on patients by connecting complex electrodes to their heads.

[0011] In the Chinese invention patent entitled "A millimeter-wave-based non-contact vital signs monitoring method and system," which was authorized on May 14, 2024, with the authorization announcement number CN116831540B, the method transmits a millimeter-wave radar signal to the target body and receives an echo signal reflected by the target body's chest vibration; the echo signal is mixed with the transmitted millimeter-wave radar signal to obtain an intermediate frequency signal, and the frequency and phase of the intermediate frequency signal are extracted; a frequency domain signal is constructed based on the frequency and phase of the intermediate frequency signal, and the respiratory signal is filtered out based on the difference in spectral characteristics between the respiratory signal and the heartbeat signal to obtain a heartbeat signal. This invention can perform real-time, efficient, non-contact measurement of key vital signs such as the target body's respiratory and heartbeat signals, enabling users to understand the current vital signs information such as the respiratory and heartbeat frequencies of the monitored subject, with small error fluctuations and high measurement accuracy.

[0012] Similarly, in the Chinese invention patent entitled “A Method and System for Detecting Vital Signs of a Moving Target”, which was authorized on July 12, 2024, with the authorization announcement number CN114403820B, a chirp signal with different slope frequencies is transmitted based on MIMO technology to obtain multiple sets of signal data with different distance resolutions; target distance information is obtained and the target phase signal is extracted; based on the modal decomposition algorithm, the heartbeat signal and respiratory signal of the target are decomposed from the target phase signal to estimate the target heart rate and respiratory rate. The present invention uses non-contact millimeter-wave radar detection to detect the respiratory rate and heart rate of a moving target. Compared with wearable and contact devices, it provides a pleasant experience to the user while ensuring privacy; compared with other traditional non-contact vital signs monitoring methods, this method does not require the monitored person to be sitting in a chair or lying in bed with the chest facing the radar equipment, and supports the target to carry out normal activities in the monitoring area to achieve vital signs monitoring.

[0013] However, existing millimeter-wave radar-based vital signs monitoring methods mainly obtain vital signs such as breathing and heartbeat signals, and are unable to monitor the state of consciousness. Summary of the Invention

[0014] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a vital signs and consciousness status monitoring system based on active and passive radars, so as to accurately collect vital signs signals and EEG signals, and realize real-time, continuous and dynamic monitoring of patients' vital signs and consciousness status.

[0015] To achieve the above-mentioned purpose, the present invention provides a vital sign and consciousness monitoring system based on active and passive radars, comprising:

[0016] A radar excitation source, used to generate a millimeter-wave radar excitation signal;

[0017] The millimeter-wave radar excitation signal is amplified by the millimeter-wave transmitter in the transmitter module and then transmitted to the low-sidelobe, high-gain transmitting antenna, which transmits the millimeter-wave radar signal to the monitored person.

[0018] It is characterized by further comprising:

[0019] A dual-band receiving antenna with low sidelobe, high gain, and high sensitivity is used to receive the millimeter-wave radar signal (millimeter-wave echo signal) reflected by the monitored person, as well as the radiated brain wave signal, and transmit them to a high-sensitivity receiver module. The millimeter-wave echo signal reflects vital signs, and the brain wave signal reflects the state of consciousness.

[0020] The high-sensitivity receiver module consists of two parts: a millimeter-wave receiver and an extremely low-frequency high-sensitivity receiver. The millimeter-wave receiver is used to condition millimeter-wave echo signals, while the extremely low-frequency high-sensitivity receiver is used to condition brain wave signals.

[0021] The signal processing module is used to sample and analyze the conditioned millimeter wave echo signal and brain wave signal to obtain the vital and brain wave characteristic data of the monitored person;

[0022] A data storage module is used to store the vital and brain wave characteristic data obtained by the signal processing module when the monitored person is a normal person;

[0023] The alarm module is used to compare the vital signs and brain wave characteristic data analyzed and processed by the signal processing module with the vital signs and brain wave characteristic data stored by the data storage module when the monitored person is a patient. When the difference is greater than the threshold, it indicates that the patient's vital signs or consciousness state is abnormal, and an early warning signal is issued.

[0024] The object of the invention of the present invention is achieved like this:

[0025] The present invention is a vital sign and consciousness status monitoring system based on active and passive radars. On the basis of existing millimeter-wave radar monitoring of vital signs, it adopts a low-sidelobe, high-gain, high-sensitivity dual-frequency receiving antenna to receive millimeter-wave echo signals and brain wave signals, that is, it can receive Ka-band and brain wave band signals. At the same time, an extremely low frequency (brain wave band signal frequency band: 0-20MHz) high-sensitivity receiver is added to the high-sensitivity receiver module to condition the brain wave radiation signal, and then sampling, analysis and processing are performed in the signal processing module. The data results of the analysis and processing are compared with the data results of the analysis and processing of normal people stored in the data storage module. When the difference is greater than a threshold, it indicates that the patient's vital signs or consciousness status are abnormal, and an early warning signal is issued.

[0026] The present invention is a non-contact monitoring system based on active and passive radars. It ensures the precise acquisition and high-speed processing of patients' vital signs and EEG signals, enabling real-time, continuous, dynamic, and widely applicable monitoring of patients' vital signs and consciousness. This effectively overcomes the limitations of traditional disease monitoring and assessment methods in monitoring consciousness in elderly patients with chronic diseases and those at risk of delirium after surgery, which lack real-time, convenient, and widely applicable features. It significantly reduces the workload of medical staff and provides solid technical support for early warning and interventional treatment of changes in patients' physical condition, thereby reducing patients' sequelae. Furthermore, the present invention enables uninterrupted, contactless monitoring of hospitalized patients' vital signs, thereby facilitating their rapid recovery under good rest conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the principle of a specific embodiment of the active and passive radar-based vital sign and consciousness status monitoring system of the present invention;

[0028] Figure 2 yes Figure 1 The schematic diagram of the millimeter wave transmitter shown;

[0029] Figure 3 yes Figure 1 Schematic diagram of the millimeter wave receiver shown;

[0030] Figure 4 yes Figure 1 The schematic diagram of the extremely low frequency high sensitivity receiver shown in FIG.

[0031] Figure 5 yes Figure 1 The structural diagram of the self-calibration module is shown;

[0032] Figure 6 This is a flow chart for amplitude and phase self-calibration of the radar receiving and transmitting links;

[0033] Figure 7 It is a schematic diagram of monitoring a monitored person by the vital signs and consciousness status monitoring system based on active and passive radars of the present invention. DETAILED DESCRIPTION

[0034] The following describes the specific embodiments of the present invention in conjunction with the accompanying drawings so that those skilled in the art can better understand the present invention. It should be noted that in the following description, when detailed descriptions of known functions and designs may dilute the main content of the present invention, such descriptions will be omitted here.

[0035] Figure 1 It is a schematic diagram of the principle of a specific implementation of the vital signs and consciousness status monitoring system based on active and passive radars of the present invention.

[0036] In this embodiment, if Figure 1 As shown, the vital signs and consciousness status monitoring system based on active and passive radars of the present invention includes: a radar excitation source 1, a transmitter module 2, a low-sidelobe and high-gain transmitting antenna 3, a low-sidelobe, high-gain and high-sensitivity dual-frequency receiving antenna 4, a high-sensitivity receiver module 5, a signal processing module 6, a data storage module 7 and an alarm module 8.

[0037] The radar excitation source 1 generates a millimeter-wave radar excitation signal, which is amplified by the millimeter-wave transmitter 201 in the transmitter module 2 and then transmitted to the low-sidelobe and high-gain transmitting antenna 3 to transmit the millimeter-wave radar signal to the monitored person.

[0038] In this embodiment, radar excitation source 1 is a highly stable signal generator module capable of outputting high-frequency, wide-band signals. This improved radar excitation source, based on this highly stable signal generator module, enables software-based radar design, enabling the transmission and reception of detection signals required for monitoring using an open system architecture.

[0039] The transmitter module 2 is composed of a millimeter wave (Ka band) transmitter 201, a direct circuit 202 and a first microwave switch 203. Figure 2As shown, millimeter-wave transmitter 201 consists of an attenuator 2011, a driver amplifier 2012, a power amplifier 2013, a coupler 2014, and a detector 2015. Attenuator 2011 attenuates the millimeter-wave radar excitation signal, which is then amplified by driver amplifier 2012 and further amplified by power amplifier 2013. After amplification by power amplifier 2013, the millimeter-wave radar excitation signal is split into two parts by coupler 2014. One part is transmitted to detector 2015 for output signal detection, and the detection result is fed back to attenuator 2011 for signal level control. The other part (after passing through self-calibration module 9) is transmitted to low-sidelobe, high-gain transmitting antenna 3 to radiate into open space, i.e., transmit millimeter-wave radar signals toward the monitored person. Low-sidelobe, high-gain transmitting antenna 3 is a Ka-band antenna. Among them, the driver amplifier is used to pre-amplify the transmitted signal so that the power amplifier 2013 can further amplify it. The power amplifier 2013 is a high-power amplifier, which is implemented by a simple bridge or Wilkison power synthesis and is used to amplify the signal power according to the design requirements. The coupler 2014 and the detector 2015 detect the signal power after being amplified by the power amplifier 2013. The attenuator 2011 constitutes an automatic level balancing circuit. When the signal power is large, the attenuation ratio is increased, and vice versa, the attenuation ratio is reduced.

[0040] The low-sidelobe, high-gain, and high-sensitivity dual-band receiving antenna 4 receives the millimeter-wave radar signal (millimeter-wave echo signal) reflected by the monitored person, as well as the radiated brainwave signal, and transmits it to the high-sensitivity receiver module 5. The millimeter-wave echo signal reflects vital signs, and the brainwave signal reflects the state of consciousness. The low-sidelobe, high-gain, and high-sensitivity dual-band receiving antenna 4 is a co-aperture microstrip antenna covering the extremely low frequency (0-20 MHz) and Ka bands.

[0041] The high-sensitivity receiver module 5 consists of two parts: a millimeter wave receiver 501 and an extremely low frequency high-sensitivity receiver 502. The millimeter wave receiver 501 is used to condition the millimeter wave echo signal, and the extremely low frequency high-sensitivity receiver 502 is used to condition the brain wave signal.

[0042] Millimeter-wave receiver 501 covers the Ka band and comprises a limiter 5011, a low-noise amplifier 5012, a downconverter 5013, a filter 5014, and a demodulator 5015. The reflected millimeter-wave radar signal, or millimeter-wave echo signal, is received by the low-sidelobe, high-gain, and high-sensitivity dual-band receiving antenna 4 and then transmitted to the limiter 5011. The limiter 5011 limits high-power signals exceeding the threshold. The signals are then amplified by the low-noise amplifier 5012, down-converted by the downconverter 5013, filtered out of band by the filter 5014, and demodulated by the demodulator 5015 to produce the conditioned millimeter-wave echo signal. This conditioned millimeter-wave echo signal is the IQ signal.

[0043] The extremely low frequency (ELF) high-sensitivity receiver 502 covers the ELF band, also known as the EEG band, and comprises a limiter 5021, a low-noise amplifier 5022, a filter 5023, and a demodulator 5024. The radiated EEG signal is received by the low-sidelobe, high-gain, and high-sensitivity dual-band receiving antenna 4 and then transmitted to the limiter 5021. The limiter 5021 limits high-power signals exceeding the threshold. The signals are then amplified by the low-noise amplifier 5022, filtered out of band by the filter 5023, and demodulated by the demodulator 5024 to form the conditioned EEG signal. This conditioned EEG signal is the IQ signal.

[0044] Signal processing module 6 samples and analyzes the conditioned millimeter wave echo signal and brain wave signal to obtain vital and brain wave characteristic data of the monitored person. In specific implementations, the millimeter wave echo signal can also be processed to obtain breathing and heartbeat signals and their corresponding frequencies.

[0045] The data storage module 7 is used to store the vital signs and brainwave characteristic data analyzed and processed by the signal processing module when the monitored person is normal. It can also store the vital signs and consciousness signal characteristics of abnormal patients for later scientific research evaluation and analysis. The alarm module 8 is used to compare the vital signs and brainwave characteristic data analyzed and processed by the signal processing module with the vital signs and brainwave characteristic data stored by the data storage module when the monitored person is a patient. If the difference is greater than a threshold, it indicates that the patient's vital signs or consciousness are abnormal, and a warning signal is issued.

[0046] In this embodiment, the signal processing module 6 is designed with a PXIe bus structure, which can sample the intermediate frequency echo signal, control the interface of the radar front end, and analyze and process the echo characteristics.

[0047] Since the errors caused by active devices such as low-noise amplifiers in millimeter-wave receivers and extremely low-frequency high-sensitivity receivers are important factors affecting monitoring accuracy, and the errors caused by them are inconsistent under different working conditions, the impact of the errors on the monitoring results cannot be deducted by calibrating their errors in advance. Therefore, in order to obtain more accurate monitoring results, the receiving link errors need to be accurately calibrated.

[0048] like Figure 1 As shown in FIG, the present invention's vital signs and consciousness status monitoring system based on active and passive radars further includes a self-calibration module 9. Figure 5 As shown, the self-calibration module 9 consists of a coupler 901, a second microwave switch 902, a first matching impedance 903, a third microwave switch 904, a second matching impedance 905, and a fourth microwave switch 906. The input of the coupler 901 comes from the transmitter module 2, and the output is two-way, one to the connection terminal 1 of the second microwave switch 902, and the other to the connection terminal 1 of the third microwave switch 904. The connection terminals 2 and 3 of the second microwave switch 902 are respectively connected to the first matching impedance 903 and the low-sidelobe high-gain transmitting antenna 3. The second microwave switch 902 selects the connection terminal 1 to be connected to the connection terminal 2 or the connection terminal 3. End 3 is connected, connection ends 2 and 3 of the third microwave switch 904 are connected to the second matching impedance 905 and the high-sensitivity receiver module 5, respectively. The third microwave switch 904 selects connection end 1 to be connected to connection end 2 or connection end 3. Connection ends 1 and 2 of the fourth microwave switch 906 are connected to the low-sidelobe, high-gain, and high-sensitivity dual-frequency receiving antenna 4 and the high-sensitivity receiver module 5, respectively. When closed, the low-sidelobe, high-gain, and high-sensitivity dual-frequency receiving antenna 4 is connected to the high-sensitivity receiver module 5, and when disconnected, the low-sidelobe, high-gain, and high-sensitivity dual-frequency receiving antenna 4 is disconnected from the high-sensitivity receiver module 5;

[0049] The transmitter module 2 also includes a through circuit 202 and a first microwave switch 203. The connection terminal 1 of the first microwave switch 203 is connected to the millimeter-wave radar excitation signal generated by the radar excitation source 1, and then one of the connection terminals 2, 3, and 4 is selected for connection, wherein the connection terminal 2 is connected to the through circuit 202, the connection terminal 3 is connected to the millimeter-wave transmitter 201, and the connection terminal 4 is empty.

[0050] In this embodiment, the radar excitation source 1 covers the extremely low frequency 0-20 MHz and millimeter wave bands. During calibration, an excitation signal is used to send an extremely low frequency signal to calibrate the link, but this is not required during testing.

[0051] First, if Figure 6 As shown, the radar receiving chain is calibrated for amplitude and phase:

[0052] Step S101: Select the connection terminal 4 of the first microwave switch 203 to connect or disconnect the radar excitation source 1. The millimeter-wave radar excitation signal S1(ω) generated by the radar excitation source 1 is:

[0053]

[0054] Among them, |S1(ω)| is the amplitude of the millimeter wave radar excitation signal, is the phase of the millimeter-wave radar excitation signal, ω is the angular frequency of the millimeter-wave radar excitation signal;

[0055] Step S102: Select the connection terminal 2 of the first microwave switch 203 to connect, and the millimeter-wave radar excitation signal S1(ω) is input to the coupler 901 of the self-calibration module 9 via the first microwave switch 203 and the direct circuit 202 in the transmitter module 2. Select the connection terminal 2 of the second microwave switch 902 to connect, that is, the coupler 901 is connected to the first matching impedance 903. At the same time, select the connection terminal 3 of the third microwave switch 904 to connect, that is, the coupler 901 is connected to the high-sensitivity receiver module 5. The fourth microwave switch 906 is disconnected. In this way, the millimeter-wave radar excitation signal S1(ω) is input to the millimeter-wave receiver 501 in the high-sensitivity receiver module 5 via the first microwave switch 203, the direct circuit 202, the coupler 901 in the self-calibration module 9, and the third microwave switch 904 in the transmitter module 2 for conditioning. The conditioned millimeter-wave radar signal is S2(ω):

[0056]

[0057] Among them, |S2(ω)| is the amplitude of the conditioned millimeter-wave radar signal, is the phase of the conditioned millimeter-wave radar signal;

[0058] Step S103: Calculate the amplitude change and phase offset of the conditioned millimeter-wave radar signal S2(ω) relative to the millimeter-wave radar excitation signal S1(ω), i.e., calibrate the total error L between the self-calibration module 9 and the millimeter-wave receiver via the direct circuit 202. S1 :

[0059]

[0060] in, is the total error L S1 The amplitude, is the total error L S1 Phase;

[0061] Step S104: Using the error parameter L of the third microwave switch 904 in the self-calibration module 9 K1 :

[0062]

[0063] Among them, |L K1 (ω)| is the error parameter L K1 The amplitude, is the error parameter L K1 Phase;

[0064] The error parameter L of the fourth microwave switch 906 K2 :

[0065]

[0066] Among them, |L K2 (ω)| is the error parameter L K2 The amplitude, is the error parameter L K2 Phase;

[0067] The error parameter L of the through circuit 202 T1 :

[0068]

[0069] Among them, |L T1 (ω)| is the error parameter L T1 The amplitude, is the error parameter L T1 Phase;

[0070] Combined total error L S1 Perform vector calculation correction to obtain the radar receiving link error L during active detection S2 :

[0071]

[0072] Similarly, the millimeter-wave radar excitation signal S1(ω) generated by the radar excitation source 1 in step S101 is converted into an extremely low frequency signal of 0-20 MHz, and is input into the extremely low frequency high sensitivity receiver 502 in the high sensitivity receiver module 5 in step S102 for conditioning to obtain the radar receiving link error during passive detection, which is recorded as L S ′2.

[0073] Then, when the active detection mode is performed, the radar excitation source 1 is adjusted to the Ka band to generate a millimeter-wave radar excitation signal. At the same time, for the first microwave switch 203, the connection end 3 is selected for connection, and the millimeter-wave radar excitation signal is input into the millimeter-wave transmitter 201. For the second microwave switch 902 in the self-calibration module 9, the connection end 3 is selected for connection. In this way, the millimeter-wave radar excitation signal is amplified by the millimeter-wave transmitter 201 in the transmitter module 2 and transmitted to the low-sidelobe, high-gain transmitting antenna 3, which transmits the millimeter-wave radar signal to the monitored person. For the third microwave switch 904 in the self-calibration module 9, the connection end 2 is selected for connection, that is, the second matching impedance 905 is connected to play the role of impedance matching. The fourth microwave switch 906 in the self-calibration module 9 is closed. In this way, the low-sidelobe, high-gain, and high-sensitivity dual-frequency receiving antenna 4 receives the millimeter-wave radar signal reflected by the monitored person, that is, the millimeter-wave echo signal, and transmits it to the high-sensitivity receiver module 5. After conditioning by the millimeter-wave receiver 501, the conditioned millimeter-wave echo signal T1 is obtained.

[0074] After sampling in the signal processing module 6, the millimeter wave echo signal T1 is calibrated in amplitude and phase before analysis and processing to obtain the millimeter wave echo signal T before the radar enters the receiving link. R1 :

[0075]

[0076] For millimeter wave echo signal T R1 Perform analysis and processing to obtain vital characteristic data of the monitored person;

[0077] When in passive detection mode, the radar excitation source 1 is turned off or the connection terminal 4 of the first microwave switch 203 is selected for connection, the connection terminal 2 of the second microwave switch 902 is selected for connection, that is, the coupler 901 is connected to the first matching impedance 903, the connection terminal 2 of the third microwave switch 904 is selected for connection, that is, the coupler 901 is connected to the second matching impedance 905, and the fourth microwave switch 906 is closed. In this way, the low-sidelobe, high-gain, and high-sensitivity dual-frequency receiving antenna 4 receives the brain wave signals radiated by the monitored person and transmits them to the high-sensitivity receiver module 5. After conditioning by the extremely low-frequency, high-sensitivity receiver 502, the conditioned brain wave signal T1′ is obtained.

[0078] After sampling in the signal processing module 6, the amplitude and phase of the brain wave signal T1′ are calibrated before analysis and processing to obtain the brain wave signal T before the radar enters the receiving link. R '1:

[0079]

[0080] For brain wave signal T R ′1 is analyzed and processed to obtain the brain wave characteristic data of the monitored person.

[0081] In this embodiment, a signal generating module with high frequency stability relative to the frequency changes of the millimeter wave echo signal and the brain wave radiation signal is used as the radar excitation source 1, and the frequency of the conditioned millimeter wave echo signal and the brain wave signal can be calibrated.

[0082] The steps for self-calibration of the millimeter wave receiver 501 frequency are as follows:

[0083] For the first microwave switch 203, the connection terminal 3 is selected for connection, and the connection terminal 2 of the second microwave switch 902 is selected for connection, that is, the coupler 901 is connected to the first matching impedance 903. At the same time, the connection terminal 3 of the third microwave switch 904 is selected for connection, that is, the coupler 901 is connected to the high-sensitivity receiver module 5. The fourth microwave switch 906 is disconnected. The radar excitation source 1 generates a millimeter-wave radar excitation signal with a frequency of ω0. After passing through the first microwave switch 203 in the transmitter module 2, the millimeter-wave transmitter 201, the self-calibration module 9, and the millimeter-wave receiver 501 in the high-sensitivity receiver module 5, a conditioned millimeter-wave radar signal is obtained, whose frequency is ω1. The frequency offset of the millimeter-wave receiver 501 obtained by using the above two frequencies ω1 and ω0 is Δω:

[0084] Δω=ω1-ω0

[0085] Using the frequency offset Δω, the frequency of the millimeter wave echo signal T1 is calibrated in the active detection mode. The frequency of the calibrated millimeter wave echo signal is:

[0086] ω R1 =ω T1 -Δω

[0087] Among them, ω T1 is the frequency of the millimeter wave echo signal T1 measured by the radar millimeter wave receiver, ω R1 is the frequency of the calibrated millimeter wave echo signal, that is, the millimeter wave echo signal T before the radar enters the receiving link R1 frequency.

[0088] The frequency self-calibration steps of the low-frequency high-sensitivity receiver 502 are as follows:

[0089] For the first microwave switch 203, the connection terminal 2 is selected for connection, and the connection terminal 2 of the second microwave switch 902 is selected for connection, that is, the coupler 901 is connected to the first matching impedance 903. At the same time, the connection terminal 3 of the third microwave switch 904 is selected for connection, that is, the coupler 901 is connected to the high-sensitivity receiver module 5. The fourth microwave switch 906 is disconnected. The radar excitation source 1 generates an extremely low frequency signal with a frequency of ω0′. After passing through the first microwave switch 203 in the transmitter module 2, the direct circuit 202, the self-calibration module 9, and the extremely low frequency and high-sensitivity receiver 502 in the high-sensitivity receiver module 5, a conditioned extremely low frequency signal with a frequency of ω1′ is obtained. The frequency offset of the low-frequency and high-sensitivity receiver 502 is obtained using the above two frequencies ω′1 and ω′0:

[0090] Δω′=ω′1-ω′0

[0091] Using the frequency offset Δω′, the brain wave signal T1′ is frequency calibrated in the passive detection mode. The calibrated brain wave signal frequency is:

[0092] ω′ R1 =ω′ T1 -Δω′

[0093] Among them, ω′ T1 is the frequency of the brain wave signal T1′ measured by the radar's extremely low frequency high-sensitivity receiver, ω′ R1 is the calibrated brainwave signal frequency, that is, the brainwave signal T′ before the radar enters the receiving link R1 frequency.

[0094] In this embodiment, the present invention further includes a timing control module 10, which uses a PLL inside the FPGA to generate a clock signal of a frequency required for coherent signal processing, ensuring that the timing of each hardware control signal strictly meets the timing design requirements.

[0095] Figure 7 It is a schematic diagram of monitoring a monitored person by the vital signs and consciousness status monitoring system based on active and passive radars of the present invention.

[0096] In this embodiment, if Figure 7 As shown, the vital signs and consciousness status monitoring system based on active and passive radars of the present invention utilizes active and passive detection to perform uninterrupted and contactless continuous monitoring of the vital signs and consciousness status of the monitored person, thereby facilitating the rapid recovery of the monitored person (patient) under good rest conditions.

[0097] Although the above describes the illustrative specific embodiments of the present invention to facilitate understanding of the present invention by those skilled in the art, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concepts of the present invention are protected.

Claims

1. A vital sign and consciousness monitoring system based on active and passive radar, comprising: A radar excitation source, used to generate a millimeter-wave radar excitation signal; The millimeter-wave radar excitation signal is amplified by the millimeter-wave transmitter in the transmitter module and then transmitted to the low-sidelobe, high-gain transmitting antenna, which transmits the millimeter-wave radar signal to the monitored person. It is characterized by further comprising: A dual-band receiving antenna with low sidelobe, high gain, and high sensitivity is used to receive the millimeter-wave radar signal (i.e., millimeter-wave echo signal) reflected by the monitored person, as well as the radiated brainwave signal, and transmit it to a high-sensitivity receiver module. The millimeter-wave echo signal reflects vital signs, while the brainwave radiation signal reflects the state of consciousness. The high-sensitivity receiver module consists of two parts: a millimeter-wave receiver and an extremely low-frequency high-sensitivity receiver. The millimeter-wave receiver is used to condition the millimeter-wave echo signal, and the extremely low-frequency high-sensitivity receiver is used to condition the brainwave radiation signal. The signal processing module is used to sample and analyze the conditioned millimeter wave echo signal and brain wave radiation signal to obtain the vital and brain wave characteristic data of the monitored person; A data storage module is used to store the vital and brain wave characteristic data obtained by the signal processing module when the monitored person is a normal person; The alarm module is used to compare the vital signs and brain wave characteristic data analyzed and processed by the signal processing module with the vital signs and brain wave characteristic data stored by the data storage module when the monitored person is a patient. When the difference is greater than the threshold, it indicates that the patient's vital signs or consciousness state is abnormal, and an early warning signal is issued.

2. The vital signs and consciousness status monitoring system based on active and passive radar according to claim 1 is characterized in that: Also included is a self-calibration module, consisting of a coupler, a second microwave switch, a first matching impedance, a third microwave switch, a second matching impedance, and a fourth microwave switch; The coupler has an input from the transmitter module and two outputs, one to terminal 1 of the second microwave switch and the other to terminal 1 of the third microwave switch. Terminals 2 and 3 of the second microwave switch are respectively connected to a first matching impedance, low sidelobe, and high gain transmitting antenna. The second microwave switch selects terminal 1 to be connected to terminal 2 or terminal 3. Terminals 2 and 3 of the third microwave switch are respectively connected to a second matching impedance, high sensitivity receiver module. The third microwave switch selects terminal 1 to be connected to terminal 2 or terminal 3. Terminals 1 and 2 of the fourth microwave switch are respectively connected to a low sidelobe, high gain, and high sensitivity dual-frequency receiving antenna and a high sensitivity receiver module. When the fourth microwave switch is closed, the low sidelobe, high gain, and high sensitivity dual-frequency receiving antenna is connected to the high sensitivity receiver module. When the fourth microwave switch is disconnected, the low sidelobe, high gain, and high sensitivity dual-frequency receiving antenna is disconnected from the high sensitivity receiver module. The transmitter module also includes a through circuit and a first microwave switch. The connection terminal 1 of the first microwave switch is connected to the millimeter-wave radar excitation signal generated by the radar excitation source, and then one of the connection terminals 2, 3, and 4 is selected for connection, wherein the connection terminal 2 is connected to the through circuit, the connection terminal 3 is connected to the millimeter-wave transmitter, and the connection terminal 4 is empty.

3. The vital signs and consciousness status monitoring system based on active and passive radar according to claim 1, characterized in that: First, the radar receiving chain is self-calibrated in terms of amplitude and phase: Step S101: Select the connection terminal 4 of the first microwave switch to connect or disconnect the radar excitation source. The millimeter-wave radar excitation signal S1(ω) generated by the radar excitation source is: Among them, |S1(ω)| is the amplitude of the millimeter wave radar excitation signal, is the phase of the millimeter-wave radar excitation signal, (ω) is the angular frequency of the millimeter-wave radar excitation signal; Step S102: Select the connection terminal 2 of the first microwave switch to connect, and the millimeter-wave radar excitation signal S1(ω) is input to the coupler of the self-calibration module through the first microwave switch and the direct circuit in the transmitter module. Select the connection terminal 2 of the second microwave switch to connect, that is, the coupler is connected to the first matching impedance. At the same time, select the connection terminal 3 of the third microwave switch to connect, that is, the coupler is connected to the high-sensitivity receiver module. The fourth microwave switch is disconnected. In this way, the millimeter-wave radar excitation signal S1(ω) is input to the millimeter-wave receiver in the high-sensitivity receiver module through the first microwave switch in the transmitter module, the direct circuit, the coupler in the self-calibration module, and the third microwave switch for conditioning. The conditioned millimeter-wave radar signal is S2(ω): Among them, |S2(ω)| is the amplitude of the conditioned millimeter-wave radar signal, is the phase of the conditioned millimeter-wave radar signal; Step S103: Calculate the amplitude change and phase offset of the conditioned millimeter-wave radar signal S2(ω) relative to the millimeter-wave radar excitation signal S1(ω), that is, calibrate the total error L of the transmitter module, self-calibration module, and high-sensitivity receiver module. S1 : in, is the total error L S1 The amplitude, is the total error L S1 Phase; Step S104: Using the error parameter L of the third microwave switch in the self-calibration module K1 : Among them, |L K1 (ω)| is the error parameter L K1 The amplitude, is the error parameter L K1 Phase; Error parameter L of the fourth microwave switch K2 : Among them, |L K2 (ω)| is the error parameter L K2 The amplitude, is the error parameter L K2 Phase; Error parameter L of the direct circuit T1 : Among them, |L T1 (ω)| is the error parameter L T1 The amplitude, is the error parameter L T1 Phase; Combined total error L S1 Perform vector calculation correction to obtain the radar receiving link error L during active detection S2 : Similarly, the millimeter-wave radar excitation signal S1(ω) generated by the radar excitation source in step S101 is converted into an extremely low frequency signal of 0-20 MHz, and is input into the extremely low frequency high sensitivity receiver in the high sensitivity receiver module in step S102 for conditioning to obtain the radar receiving link error during passive detection, which is recorded as L′ S2 ; Then, when the active detection mode is performed, the radar excitation source is adjusted to the Ka band to generate a millimeter-wave radar excitation signal. At the same time, for the first microwave switch, the connection end 3 is selected for connection, and the millimeter-wave radar excitation signal is input into the millimeter-wave transmitter. For the second microwave switch in the self-calibration module, the connection end 3 is selected for connection, so that the millimeter-wave radar excitation signal is amplified by the millimeter-wave transmitter in the transmitter module and transmitted to the low-sidelobe and high-gain transmitting antenna to transmit the millimeter-wave radar signal to the monitored person. For the third microwave switch in the self-calibration module, the connection end 2 is selected for connection, that is, the second matching impedance is connected to play the role of impedance matching. For the fourth microwave switch in the self-calibration module, it is closed, so that the low-sidelobe, high-gain, and high-sensitivity dual-frequency receiving antenna receives the millimeter-wave radar signal reflected by the monitored person, that is, the millimeter-wave echo signal and transmits it to the high-sensitivity receiver module, which is conditioned by the millimeter-wave receiver to obtain the conditioned millimeter-wave echo signal T1. After sampling in the signal processing module, the millimeter wave echo signal T1 is calibrated in amplitude and phase before analysis and processing to obtain the millimeter wave echo signal T before the radar enters the receiving link. R1 : For millimeter wave echo signal T R1 Perform analysis and processing to obtain vital characteristic data of the monitored person; When in passive detection mode, the radar excitation source is turned off or the connection terminal 4 of the first microwave switch is selected for connection, the connection terminal 2 of the second microwave switch is selected for connection, that is, the coupler is connected to the first matching impedance, the connection terminal 2 of the third microwave switch is selected for connection, that is, the coupler is connected to the second matching impedance, and the fourth microwave switch is closed. In this way, the low-sidelobe, high-gain, and high-sensitivity dual-frequency receiving antenna receives the brain wave signals radiated by the monitored person and transmits them to the high-sensitivity receiver module. After conditioning by the extremely low-frequency and high-sensitivity receiver, the conditioned brain wave signal T1′ is obtained; After sampling in the signal processing module, the amplitude and phase of the brain wave signal T1′ are calibrated before analysis and processing to obtain the brain wave signal T′ before the radar enters the receiving link. R1 : For brain wave signal T′ R1 Analyze and process the data to obtain the brain wave characteristic data of the monitored person.

4. The vital signs and consciousness status monitoring system based on active and passive radar according to claim 3 is characterized in that: Self-calibration of mmWave receiver frequency: For the first microwave switch, select connection terminal 3 for connection, select connection terminal 2 of the second microwave switch for connection, that is, connect the coupler to the first matching impedance. At the same time, select connection terminal 3 of the third microwave switch for connection, that is, connect the coupler to the high-sensitivity receiver module. The fourth microwave switch is disconnected. The radar excitation source generates a millimeter-wave radar excitation signal with a frequency of ω0. After passing through the first microwave switch, millimeter-wave transmitter, self-calibration module, and millimeter-wave receiver in the high-sensitivity receiver module in the transmitter module, a conditioned millimeter-wave radar signal with a frequency of ω1 is obtained. The frequency offset of the millimeter-wave receiver is obtained using the above two frequencies ω1 and ω0, which is Δω: Δω=ω1-ω0 Using the frequency offset Δω, the frequency of the millimeter wave echo signal T1 is calibrated in the active detection mode. The frequency of the calibrated millimeter wave echo signal is: oh R1 =ω T1 -See Among them, ω T1 is the frequency of the millimeter wave echo signal T1 measured by the radar millimeter wave receiver, ω R1 is the frequency of the calibrated millimeter wave echo signal, that is, the millimeter wave echo signal T before the radar enters the receiving link R1 frequency; Self-calibration of low-frequency high-sensitivity receiver frequency: For the first microwave switch, select connection terminal 2 for connection, select connection terminal 2 for connection of the second microwave switch, that is, connect the coupler to the first matching impedance, and at the same time, select connection terminal 3 of the third microwave switch for connection, that is, connect the coupler to the high-sensitivity receiver module. The fourth microwave switch is disconnected, and the radar excitation source generates an extremely low frequency signal with a frequency of ω′0. After passing through the first microwave switch, the direct circuit, the self-calibration module, and the extremely low frequency and high-sensitivity receiver in the high-sensitivity receiver module in the transmitter module, a conditioned extremely low frequency signal with a frequency of ω′1 is obtained. The frequency offset of the low-frequency and high-sensitivity receiver is obtained using the above two frequencies ω′1 and ω′0, which is Δω′: Δω′=ω′1-ω′0 Using the frequency offset Δω′, the brain wave signal T1′ is frequency calibrated in the passive detection mode. The calibrated brain wave signal frequency is: oh' R1 =ω′ T1 -See? Among them, ω′ T1 is the frequency of the brain wave signal T1′ measured by the radar's extremely low frequency high-sensitivity receiver, ω′ R1 is the brainwave signal frequency after calibration, that is, the brainwave signal T′ before the radar enters the receiving link R1 frequency.

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