Sleep monitoring equipment based on millimeter wave radar

Abstract

The invention relates to the technical field of sleep monitoring, in particular to sleep monitoring equipment based on millimeter-wave radar, which comprises a signal acquisition module used for receiving a sleep monitoring signal transmitted by the millimeter-wave radar and receiving a reflected sleep monitoring signal; the signal processing module is connected with the signal acquisition module and comprises a preprocessing unit for preprocessing the sleep monitoring signal to output an optimized signal; the analysis module is connected with the signal processing module and is used for analyzing the sleep monitoring signal and the physiological signal characteristics to output a sleep state analysis result; the storage module is used for respectively storing the sleep monitoring signal, the optimization signal, the physiological signal characteristics and the sleep state analysis result; and the control module is used for determining the center frequency of the millimeter wave radar according to the signal-to-noise ratio variable quantity of the sleep monitoring signal. The monitoring stability of the sleep monitoring equipment is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of sleep monitoring, and in particular to a sleep monitoring device based on millimeter wave radar. Background Art

[0002] In the existing technology, as people's attention to health continues to increase, sleep quality monitoring has become a highly watched field. There are many traditional sleep monitoring methods, but they all have certain limitations. Polysomnography (PSG) technology has long been regarded as the "gold standard" for sleep monitoring. It connects multiple electrodes to the human body to simultaneously record multiple physiological signals such as electroencephalogram (EEG), electrocardiogram (ECG), electrooculogram (EOG), electromyogram (EMG), etc., and then conducts a comprehensive and accurate analysis of sleep stages, respiratory events, cardiovascular status, etc. However, the shortcomings of PSG technology are also very obvious. On the one hand, its equipment is complex and expensive, and requires professional technicians to operate and debug, which not only makes the detection cost high, but also limits the popularization and application of this technology in families and general medical institutions; on the other hand, many electrodes are attached to the human body, which brings great discomfort to the subjects, seriously affecting the natural state of sleep, resulting in the monitoring results may not truly reflect the daily sleep situation.

[0003] Chinese Patent Publication No.: CN119112101A discloses a sleep sign monitoring method based on millimeter wave radar, which specifically includes the following steps: Step 1-1, data acquisition; first, the acquisition parameters of the millimeter wave radar are preset, the millimeter wave radar transmits a signal according to the preset parameters, the receiving antenna captures the reflected signal, the millimeter wave radar RF front end amplifies, mixes, and filters the received signal, obtains an intermediate frequency digital signal after sampling, and sends the sampling result to the back-end computing device; Step 1-2, feature extraction; extracts features related to sleep posture and breathing rate from the collected intermediate frequency digital signal, that is, point cloud feature generation and breathing feature extraction; Step 1-3, sleep posture recognition; the user's sleep posture is recognized by using the point cloud features and breathing features obtained after feature extraction; Step 1-4, breathing frequency estimation; according to different sleeping postures, specific parameters are used to extract effective reflection points from the point cloud data, and these reflection points are used to accurately estimate the breathing frequency through a weighted average method based on an exponential function. It can be seen that the sleep sign monitoring method based on millimeter wave radar has the problem that the radar signal is unstable due to harmonics caused by electromagnetic interference in the working environment of the millimeter wave radar, thereby causing the monitoring stability of the sleep monitoring equipment to decrease. Summary of the invention

[0004] To this end, the present invention provides a sleep monitoring device based on millimeter wave radar, which is used to overcome the problem in the prior art that the radar signal is unstable due to harmonics caused by electromagnetic interference in the working environment of the millimeter wave radar, thereby causing the monitoring stability of the sleep monitoring device to decrease.

[0005] To achieve the above-mentioned purpose, the present invention provides a sleep monitoring device based on millimeter wave radar, comprising: a signal acquisition module, which is used to receive the sleep monitoring signal transmitted by the millimeter wave radar and reflected back; a signal processing module, which is connected to the signal acquisition module, and comprises a preprocessing unit for preprocessing the sleep monitoring signal to output an optimized signal and a feature extraction unit connected to the preprocessing unit for extracting the feature of the optimized signal to output a physiological signal feature, wherein the preprocessing unit comprises a filter for filtering the sleep monitoring signal; an analysis module, which is connected to the signal processing module, and is used to analyze the sleep monitoring signal and the physiological signal feature. The sleep state analysis result is outputted by analyzing the sleep state. A storage module is respectively connected to the signal acquisition module, the signal processing module and the analysis module, and is used to store the sleep monitoring signal, the optimization signal, the physiological signal characteristics and the sleep state analysis result respectively. A control module is respectively connected to the signal acquisition module, the signal processing module, the analysis module and the storage module, and is used to determine the center frequency of the millimeter-wave radar according to the change in the signal-to-noise ratio of the sleep monitoring signal, or to determine the cutoff frequency of the filter according to the fluctuation amplitude of the sleep monitoring signal, and to determine the clock frequency of the millimeter-wave radar according to the working frequency offset of the millimeter-wave radar per unit time.

[0006] Furthermore, the control module is used to determine whether the monitoring stability of the sleep monitoring device meets the requirements based on the signal-to-noise ratio change of the sleep monitoring signal. If the signal-to-noise ratio change of the sleep monitoring signal is greater than a preset first change, it is determined that the monitoring stability of the sleep monitoring device does not meet the requirements.

[0007] Furthermore, the control module is used to preliminarily determine that the accuracy of the sleep monitoring does not meet the requirements when the signal-to-noise ratio change of the sleep monitoring signal is greater than the preset first change and less than or equal to a preset second change, and determine whether the accuracy of the sleep monitoring meets the requirements based on the fluctuation amplitude of the sleep monitoring signal.

[0008] Furthermore, the control module is used to increase the center frequency of the millimeter wave radar when the signal-to-noise ratio change of the sleep monitoring signal is greater than the preset second change;

[0009] The increase range of the center frequency of the millimeter wave radar is determined by the difference between the signal-to-noise ratio change of the sleep monitoring signal and a preset second change.

[0010] Furthermore, the control module is used to determine whether the accuracy of sleep monitoring meets the requirements according to the fluctuation amplitude of the sleep monitoring signal. If the fluctuation amplitude of the sleep monitoring signal is greater than a preset first fluctuation amplitude, it is determined that the accuracy of sleep monitoring does not meet the requirements.

[0011] Furthermore, when the fluctuation amplitude of the sleep monitoring signal is greater than a preset second fluctuation amplitude, the control module preliminarily determines that the working performance of the millimeter-wave radar does not meet the requirements, and determines whether the working performance of the millimeter-wave radar meets the requirements based on the working frequency offset of the millimeter-wave radar per unit time.

[0012] Furthermore, the control module reduces the cutoff frequency of the filter when the fluctuation amplitude of the sleep monitoring signal is greater than the preset first fluctuation amplitude and less than or equal to the preset second fluctuation amplitude.

[0013] Furthermore, the reduction amplitude of the cutoff frequency of the filter is determined by the difference between the fluctuation amplitude of the sleep monitoring signal and a preset first fluctuation amplitude.

[0014] Furthermore, the control module is used to determine whether the working performance of the millimeter-wave radar meets the requirements based on the working frequency offset of the millimeter-wave radar in unit time. If the working frequency offset of the millimeter-wave radar in the unit time is greater than a preset offset, it is determined that the working performance of the millimeter-wave radar does not meet the requirements, and the clock frequency of the millimeter-wave radar is reduced.

[0015] Furthermore, the reduction amplitude of the clock frequency of the millimeter wave radar is determined by the difference between the operating frequency offset of the millimeter wave radar and a preset offset per unit time.

[0016] Compared with the prior art, the beneficial effect of the present invention lies in that the device of the present invention determines the center frequency of the millimeter-wave radar according to the change in the signal-to-noise ratio of the sleep monitoring signal by setting a signal acquisition module, a signal processing module, an analysis module, a storage module and a control module. Since the millimeter-wave radar may be interfered by the WiFi signal in the working environment, resulting in the appearance of harmonics, thereby making the radar signal unstable, by increasing the center frequency of the millimeter-wave radar, the interference signal received by the millimeter-wave radar can be reduced, thereby improving the stability of the signal, and the cutoff frequency of the filter is determined according to the fluctuation amplitude of the sleep monitoring signal. Since the human body micro-motion signal becomes complicated due to the change of the human body's sleeping posture when collecting the signal, This results in inaccurate feature extraction. By reducing the cutoff frequency of the filter, it can be ensured that while filtering noise, useful low-frequency signal components will not be filtered out, so that the human body micro-motion signal characteristics whose frequency becomes lower due to posture changes can be accurately extracted. The clock frequency of the millimeter-wave radar is determined according to the operating frequency offset of the millimeter-wave radar per unit time. After the millimeter-wave radar has been working for a long time, the internal components age and the performance of the internal oscillator decreases, which causes the operating frequency of the millimeter-wave radar to shift. By reducing the clock frequency of the millimeter-wave radar, the signal processing can be re-matched with the reduced operating frequency to ensure the accuracy of signal processing and improve the monitoring stability of the sleep monitoring equipment.

[0017] Furthermore, the device described in the present invention determines the center frequency of the millimeter-wave radar by setting a preset first change amount and a preset second change amount. Since the millimeter-wave radar may be interfered by the WiFi signal in the working environment, resulting in harmonics, which makes the radar signal unstable, by increasing the center frequency of the millimeter-wave radar, the interference signal received by the millimeter-wave radar can be reduced, thereby improving the stability of the signal and further improving the monitoring stability of the sleep monitoring device.

[0018] Furthermore, the device described in the present invention determines the cutoff frequency of the filter by setting a preset first fluctuation amplitude and a preset second fluctuation amplitude. Since the human body micro-motion signal becomes complicated due to changes in the human body's sleeping posture when collecting signals, which leads to inaccurate extraction of features. By reducing the cutoff frequency of the filter, it can be ensured that while filtering noise, useful low-frequency signal components will not be filtered out, so that the human body micro-motion signal characteristics whose frequency becomes lower due to posture changes can be accurately extracted, further improving the monitoring stability of the sleep monitoring equipment.

[0019] Furthermore, the device described in the present invention determines the clock frequency of the millimeter-wave radar by setting a preset offset. Since the internal components of the millimeter-wave radar age after working for a long time, the performance of the internal oscillator decreases, which causes the operating frequency of the millimeter-wave radar to shift. By reducing the clock frequency of the millimeter-wave radar, the signal processing can be re-matched with the reduced operating frequency, thereby ensuring the accuracy of the signal processing and further improving the monitoring stability of the sleep monitoring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an overall structural block diagram of a sleep monitoring device based on millimeter wave radar according to an embodiment of the present invention;

[0021] Figure 2 This is a logic flow chart of a sleep monitoring device based on millimeter wave radar according to an embodiment of the present invention;

[0022] Figure 3 This is a specific structural block diagram of a signal processing module of a sleep monitoring device based on millimeter wave radar according to an embodiment of the present invention;

[0023] Figure 4 This is a connection structure block diagram of a signal processing module and a control module of a sleep monitoring device based on millimeter wave radar according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0026] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0027] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] See also Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, they are respectively an overall structural block diagram of a sleep monitoring device based on millimeter wave radar, a logic flow chart, a specific structural block diagram of a signal processing module, and a connection structural block diagram of a signal processing module and a control module. A sleep monitoring device based on millimeter wave radar of the present invention comprises:

[0029] A signal acquisition module is used to receive the sleep monitoring signal transmitted by the millimeter-wave radar and reflected back;

[0030] a signal processing module connected to the signal acquisition module, comprising a preprocessing unit for preprocessing the sleep monitoring signal to output an optimized signal and a feature extraction unit connected to the preprocessing unit for extracting features of the optimized signal to output physiological signal features, wherein the preprocessing unit comprises a filter for filtering the sleep monitoring signal;

[0031] An analysis module, connected to the signal processing module, for analyzing the sleep monitoring signal and the physiological signal characteristics to output a sleep state analysis result;

[0032] A storage module, which is connected to the signal acquisition module, the signal processing module and the analysis module respectively, and is used to store the sleep monitoring signal, the optimization signal, the physiological signal feature and the sleep state analysis result respectively;

[0033] A control module, which is respectively connected to the signal acquisition module, the signal processing module, the analysis module and the storage module, and is used to determine the center frequency of the millimeter wave radar according to the change in the signal-to-noise ratio of the sleep monitoring signal, or to determine the cutoff frequency of the filter according to the fluctuation amplitude of the sleep monitoring signal, and to determine the clock frequency of the millimeter wave radar according to the operating frequency offset of the millimeter wave radar per unit time.

[0034] Specifically, sleep monitoring signals include breathing rate, heart rate, and body movement frequency.

[0035] Specifically, the optimized signals include an amplified respiratory rate signal, an enhanced heartbeat amplitude signal, and a prominent body movement frequency signal.

[0036] Specifically, physiological signal characteristics include respiratory frequency characteristics, heartbeat amplitude characteristics, and body movement frequency characteristics.

[0037] Specifically, the preprocessing unit also includes an amplifier for amplifying the sleep monitoring signal.

[0038] Specifically, the sleep state analysis results include light sleep stage, deep sleep stage, and rapid eye movement sleep stage.

[0039] In implementation, the device of the present invention determines the center frequency of the millimeter-wave radar according to the change in the signal-to-noise ratio of the sleep monitoring signal by setting a signal acquisition module, a signal processing module, an analysis module, a storage module and a control module. Since the millimeter-wave radar may be interfered by the WiFi signal in the working environment, resulting in harmonics, the radar signal is unstable. By increasing the center frequency of the millimeter-wave radar, the interference signal received by the millimeter-wave radar can be reduced, thereby improving the stability of the signal. The cutoff frequency of the filter is determined according to the fluctuation amplitude of the sleep monitoring signal. Since the human body's micro-motion signal becomes complicated due to the change in the human body's sleeping posture when collecting the signal, it leads to The extraction is inaccurate. By reducing the cutoff frequency of the filter, it can be ensured that while filtering noise, useful low-frequency signal components will not be filtered out, so that the human body micro-motion signal characteristics whose frequency becomes lower due to posture changes can be accurately extracted. The clock frequency of the millimeter-wave radar is determined according to the operating frequency offset of the millimeter-wave radar per unit time. After the millimeter-wave radar has been working for a long time, the internal components have aged, resulting in the performance of the internal oscillator being reduced, which causes the operating frequency of the millimeter-wave radar to shift. By reducing the clock frequency of the millimeter-wave radar, the signal processing can be re-matched with the reduced operating frequency to ensure the accuracy of signal processing and improve the monitoring stability of the sleep monitoring equipment.

[0040] Specifically, the control module is used to obtain the signal-to-noise ratio of the sleep monitoring signal within a single cycle, and calculate the change in the signal-to-noise ratio of the sleep monitoring signal. If the change in the signal-to-noise ratio of the sleep monitoring signal is greater than a preset first change, it is determined that the monitoring stability of the sleep monitoring device does not meet the requirements.

[0041] Specifically, the control module is used to preliminarily determine that the accuracy of sleep monitoring does not meet the requirements when the signal-to-noise ratio change of the sleep monitoring signal is greater than the preset first change and less than or equal to the preset second change, and determine whether the accuracy of sleep monitoring meets the requirements based on the fluctuation amplitude of the sleep monitoring signal.

[0042] It can be understood that the three intervals divided by the preset first variation and the preset second variation correspond to three situations respectively:

[0043] The first interval is when the signal-to-noise ratio change of the sleep monitoring signal is less than or equal to the preset first change, and the corresponding situation is: determining that the monitoring stability of the sleep monitoring device meets the requirements;

[0044] The second interval is when the signal-to-noise ratio change of the sleep monitoring signal is greater than the preset first change and less than or equal to the preset second change. The corresponding situation is that the human body micro-motion signal becomes complicated due to the change of the human body's sleeping posture when collecting the signal, resulting in inaccurate extraction of the feature;

[0045] The third interval is when the signal-to-noise ratio change of the sleep monitoring signal is greater than the preset second change. The corresponding situation is: in the working environment of the millimeter-wave radar, it may be interfered by the WiFi signal, resulting in harmonics, which makes the radar signal unstable.

[0046] In practice, the preset first variation is generally selected in the range of [8dB, 12dB], and the preset second variation is generally selected in the range of [13dB, 17dB].

[0047] Preferably, the preferred embodiment of the preset first variation is 10 dB, and the preferred embodiment of the preset second variation is 15 dB.

[0048] Specifically, the signal-to-noise ratio change of the sleep monitoring signal is the difference between the maximum signal-to-noise ratio and the minimum signal-to-noise ratio of the sleep monitoring signal in a single cycle.

[0049] In implementation, the device described in the present invention determines the monitoring stability of the sleep monitoring device by setting a preset first change amount and a preset second change amount, thereby reducing the impact of the decreased monitoring accuracy of the sleep monitoring device due to inaccurate determination of the monitoring stability of the sleep monitoring device, and further improving the monitoring stability of the sleep monitoring device.

[0050] Specifically, the control module is used to increase the center frequency of the millimeter wave radar when the signal-to-noise ratio change of the sleep monitoring signal is greater than the preset second change;

[0051] The increase range of the center frequency of the millimeter wave radar is determined by the difference between the signal-to-noise ratio change of the sleep monitoring signal and a preset second change.

[0052] Specifically, when the difference between the change in the signal-to-noise ratio of the sleep monitoring signal and the preset second change is within 3dB, the center frequency of the millimeter-wave radar is increased to 1.2 times the original value; when the difference between the change in the signal-to-noise ratio of the sleep monitoring signal and the preset second change exceeds 3dB, on the basis of being increased to 1.2 times the original value, the center frequency of the millimeter-wave radar is increased by 2GHz for every 2dB exceeding it. For example, the difference between the change in the signal-to-noise ratio of the sleep monitoring signal and the preset second change is 7dB. The current center frequency of the millimeter-wave radar is 60GHz, and the center frequency of the increased millimeter-wave radar is 60×1.2+2×2=76GHz.

[0053] Specifically, GHz is the unit of the center frequency of millimeter wave radar, which means gigahertz.

[0054] In implementation, the device of the present invention determines the center frequency of the millimeter-wave radar by setting a preset first change amount and a preset second change amount. Since the millimeter-wave radar may be interfered by the WiFi signal in the working environment, resulting in harmonics, the radar signal is unstable. By increasing the center frequency of the millimeter-wave radar, the interference signal received by the millimeter-wave radar can be reduced, thereby improving the stability of the signal and further improving the monitoring stability of the sleep monitoring device.

[0055] Specifically, the control module is used to obtain the sleep monitoring signal within a single cycle and calculate the fluctuation amplitude of the sleep monitoring signal. If the fluctuation amplitude of the sleep monitoring signal is greater than a preset first fluctuation amplitude, it is determined that the accuracy of the sleep monitoring does not meet the requirements.

[0056] Specifically, when the fluctuation amplitude of the sleep monitoring signal is greater than a preset second fluctuation amplitude, the control module preliminarily determines that the working performance of the millimeter-wave radar does not meet the requirements, and determines whether the working performance of the millimeter-wave radar meets the requirements based on the working frequency offset of the millimeter-wave radar per unit time.

[0057] It can be understood that the three intervals divided by the preset first fluctuation range and the preset second fluctuation range correspond to three situations respectively:

[0058] The first interval is that the fluctuation amplitude of the sleep monitoring signal is less than or equal to the preset first fluctuation amplitude, and the corresponding situation is: determining that the accuracy of the sleep monitoring meets the requirements;

[0059] The second interval is when the fluctuation amplitude of the sleep monitoring signal is greater than the preset first fluctuation amplitude and less than or equal to the preset second fluctuation amplitude. The corresponding situation is: due to the change of the human body's sleeping posture when collecting the signal, the human body micro-motion signal becomes complicated, resulting in inaccurate extraction of features;

[0060] The third interval is when the fluctuation amplitude of the sleep monitoring signal is greater than the preset second fluctuation amplitude. The corresponding situation is: due to the aging of internal components after the millimeter-wave radar has been working for a long time, the performance of the internal oscillator has been reduced, which has caused the working frequency of the millimeter-wave radar to shift.

[0061] In practice, the preset first fluctuation amplitude is generally selected in the range of [3mm, 5mm], and the preset second fluctuation amplitude is generally selected in the range of [6mm, 8mm].

[0062] Preferably, the preferred embodiment of the preset first fluctuation amplitude is 4 mm, and the preferred embodiment of the preset second fluctuation amplitude is 7 mm.

[0063] Specifically, the fluctuation amplitude of the sleep monitoring signal is the fluctuation amplitude of the breathing signal in the sleep state.

[0064] Specifically, the fluctuation amplitude of the sleep monitoring signal is the difference between the maximum value and the minimum value of the sleep monitoring signal in a single cycle.

[0065] In implementation, the device of the present invention determines the accuracy of sleep monitoring by setting a preset first fluctuation amplitude and a preset second fluctuation amplitude, thereby reducing the impact of decreased monitoring stability of the sleep monitoring device due to inaccurate determination of the accuracy of sleep monitoring, and further improving the monitoring stability of the sleep monitoring device.

[0066] Specifically, the control module reduces the cutoff frequency of the filter when the fluctuation amplitude of the sleep monitoring signal is greater than the preset first fluctuation amplitude and less than or equal to the preset second fluctuation amplitude.

[0067] Specifically, the reduction amplitude of the cutoff frequency of the filter is determined by the difference between the fluctuation amplitude of the sleep monitoring signal and the preset first fluctuation amplitude.

[0068] Specifically, when the difference between the fluctuation amplitude of the sleep monitoring signal and the preset first fluctuation amplitude is within 2mm, the cutoff frequency of the filter is reduced to 0.9 times the original value; when the difference between the fluctuation amplitude of the sleep monitoring signal and the preset first fluctuation amplitude exceeds 2mm, on the basis of being reduced to 0.9 times the original value, the cutoff frequency of the filter is reduced by 1Hz for every 1mm exceeding it. For example, the difference between the fluctuation amplitude of the sleep monitoring signal and the preset first fluctuation amplitude is 4mm, the current cutoff frequency of the filter is 20Hz, and the cutoff frequency of the filter after reduction is 20×0.9-1×2=16Hz.

[0069] In implementation, the device described in the present invention determines the cutoff frequency of the filter by setting a preset first fluctuation amplitude and a preset second fluctuation amplitude. Since the human body micro-motion signal becomes complicated due to changes in the human body's sleeping posture when collecting signals, it leads to inaccurate extraction when extracting features. By reducing the cutoff frequency of the filter, it can be ensured that while filtering noise, useful low-frequency signal components will not be filtered out, so that the human body micro-motion signal characteristics whose frequency becomes lower due to posture changes can be accurately extracted, further improving the monitoring stability of the sleep monitoring equipment.

[0070] Specifically, the control module is used to obtain the operating frequency of the millimeter-wave radar per unit time and calculate the operating frequency offset of the millimeter-wave radar per unit time. If the operating frequency offset of the millimeter-wave radar per unit time is greater than a preset offset, it is determined that the working performance of the millimeter-wave radar does not meet the requirements, and the clock frequency of the millimeter-wave radar is reduced.

[0071] It can be understood that the two intervals divided by the preset offset correspond to two situations:

[0072] The first interval is that the working frequency offset of the millimeter wave radar in unit time is less than or equal to the preset offset, and the corresponding situation is: it is determined that the working performance of the millimeter wave radar meets the requirements;

[0073] The second interval is that the operating frequency offset of the millimeter-wave radar per unit time is greater than the preset offset. The corresponding situation is: due to the aging of internal components after the millimeter-wave radar has been working for a long time, the performance of the internal oscillator has decreased, resulting in the deviation of the operating frequency of the millimeter-wave radar.

[0074] In practice, the preset offset is generally selected in the range of [1MHz / s, 3MHz / s].

[0075] Preferably, a preferred embodiment of the preset offset is 2 MHz / s.

[0076] Specifically, MHz is the operating frequency offset of the millimeter-wave radar per unit time, which means megahertz per second.

[0077] In implementation, the device of the present invention determines the working performance of the millimeter-wave radar by setting a preset offset, thereby reducing the impact of the decreased monitoring stability of the sleep monitoring device due to inaccurate determination of the working performance of the millimeter-wave radar, and further improving the monitoring stability of the sleep monitoring device.

[0078] Specifically, the reduction amplitude of the clock frequency of the millimeter wave radar is determined by the difference between the working frequency offset of the millimeter wave radar and the preset offset per unit time.

[0079] Specifically, when the difference between the working frequency offset of the millimeter-wave radar and the preset offset per unit time is within 1MHz / s, the clock frequency of the millimeter-wave radar is reduced to 0.92 times of the original; when the difference between the working frequency offset of the millimeter-wave radar and the preset offset per unit time exceeds 1MHz / s, on the basis of being reduced to 0.92 times of the original, the clock frequency of the millimeter-wave radar is reduced by 3MHz for every 0.5MHz / s exceeding it. For example, the difference between the working frequency offset of the millimeter-wave radar and the preset offset per unit time is 2MHz / s, the current clock frequency of the millimeter-wave radar is 50MHz, and the reduced clock frequency of the millimeter-wave radar is 50×0.92-3×2=40MHz.

[0080] In implementation, the device described in the present invention determines the clock frequency of the millimeter-wave radar by setting a preset offset. Since the internal components of the millimeter-wave radar age after working for a long time, the performance of the internal oscillator decreases, which causes the operating frequency of the millimeter-wave radar to shift. By reducing the clock frequency of the millimeter-wave radar, the signal processing can be re-matched with the reduced operating frequency, thereby ensuring the accuracy of the signal processing and further improving the monitoring stability of the sleep monitoring device.

[0081] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A sleep monitoring device based on millimeter wave radar, characterized in that: include: A signal acquisition module is used to receive the sleep monitoring signal transmitted by the millimeter-wave radar and reflected back; a signal processing module connected to the signal acquisition module, comprising a preprocessing unit for preprocessing the sleep monitoring signal to output an optimized signal and a feature extraction unit connected to the preprocessing unit for extracting features of the optimized signal to output physiological signal features, wherein the preprocessing unit comprises a filter for filtering the sleep monitoring signal; An analysis module, connected to the signal processing module, for analyzing the sleep monitoring signal and the physiological signal characteristics to output a sleep state analysis result; A storage module, which is connected to the signal acquisition module, the signal processing module and the analysis module respectively, and is used to store the sleep monitoring signal, the optimization signal, the physiological signal feature and the sleep state analysis result respectively; A control module, which is respectively connected to the signal acquisition module, the signal processing module, the analysis module and the storage module, and is used to determine the center frequency of the millimeter wave radar according to the change in the signal-to-noise ratio of the sleep monitoring signal, or to determine the cutoff frequency of the filter according to the fluctuation amplitude of the sleep monitoring signal, and to determine the clock frequency of the millimeter wave radar according to the operating frequency offset of the millimeter wave radar per unit time.

2. The sleep monitoring device based on millimeter wave radar according to claim 1, characterized in that: The control module is used to determine whether the monitoring stability of the sleep monitoring device meets the requirements according to the signal-to-noise ratio change of the sleep monitoring signal. If the signal-to-noise ratio change of the sleep monitoring signal is greater than a preset first change, it is determined that the monitoring stability of the sleep monitoring device does not meet the requirements.

3. The sleep monitoring device based on millimeter wave radar according to claim 2, characterized in that: The control module is used to preliminarily determine that the accuracy of sleep monitoring does not meet the requirements when the signal-to-noise ratio change of the sleep monitoring signal is greater than the preset first change and less than or equal to the preset second change, and determine whether the accuracy of sleep monitoring meets the requirements based on the fluctuation amplitude of the sleep monitoring signal.

4. The millimeter wave radar-based sleep monitoring device according to claim 3, characterized in that: The control module is used to increase the center frequency of the millimeter wave radar when the signal-to-noise ratio change of the sleep monitoring signal is greater than the preset second change; The increase range of the center frequency of the millimeter wave radar is determined by the difference between the signal-to-noise ratio change of the sleep monitoring signal and a preset second change.

5. The millimeter wave radar-based sleep monitoring device according to claim 4, characterized in that: The control module is used to determine whether the accuracy of sleep monitoring meets the requirements according to the fluctuation amplitude of the sleep monitoring signal. If the fluctuation amplitude of the sleep monitoring signal is greater than a preset first fluctuation amplitude, it is determined that the accuracy of sleep monitoring does not meet the requirements.

6. The millimeter wave radar-based sleep monitoring device according to claim 5, characterized in that: When the fluctuation amplitude of the sleep monitoring signal is greater than a preset second fluctuation amplitude, the control module preliminarily determines that the working performance of the millimeter-wave radar does not meet the requirements, and determines whether the working performance of the millimeter-wave radar meets the requirements based on the working frequency offset of the millimeter-wave radar per unit time.

7. The millimeter wave radar-based sleep monitoring device according to claim 6, characterized in that: The control module reduces the cutoff frequency of the filter when the fluctuation amplitude of the sleep monitoring signal is greater than the preset first fluctuation amplitude and less than or equal to the preset second fluctuation amplitude.

8. The millimeter wave radar-based sleep monitoring device according to claim 7, characterized in that: The reduction amplitude of the cutoff frequency of the filter is determined by the difference between the fluctuation amplitude of the sleep monitoring signal and the preset first fluctuation amplitude.

9. The millimeter wave radar-based sleep monitoring device according to claim 8, characterized in that: The control module is used to determine whether the working performance of the millimeter-wave radar meets the requirements according to the working frequency offset of the millimeter-wave radar in unit time. If the working frequency offset of the millimeter-wave radar in the unit time is greater than the preset offset, it is determined that the working performance of the millimeter-wave radar does not meet the requirements, and the clock frequency of the millimeter-wave radar is reduced.

10. The sleep monitoring device based on millimeter wave radar according to claim 9, characterized in that: The reduction amplitude of the clock frequency of the millimeter wave radar is determined by the difference between the working frequency offset of the millimeter wave radar and the preset offset within a unit time.

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