Indoor vital signs sensing device and sensing method based on SLAM technology

Abstract

The present invention provides an indoor vital signs sensing device and sensing method based on SLAM technology, comprising a SLAM mobile detection vehicle placed on the ground and a positioning radar structure installed on the wall, wherein the positioning radar structure communicates with the SLAM mobile detection vehicle, and the SLAM mobile detection vehicle is provided with a laser radar for scanning the surrounding environment, an odometer for obtaining the distance and direction information of an object, and an inertial measurement unit for measuring the acceleration and angular velocity of the vehicle. Through the SLAM simultaneous positioning and mapping technology, the path is automatically calculated, obstacles are automatically avoided, and the vehicle drives to the vicinity of the monitoring target. The millimeter wave radar on the vehicle activates the vital signs of the monitored object, realizes accurate monitoring of the vital signs, and promptly issues an alarm for dangers occurring in the ward, thereby ensuring the safety of the monitored object.

Description

Technical Field

[0001] The present invention belongs to the field of smart health care technology, and in particular relates to an indoor vital sign sensing device and a sensing method based on SLAM technology. Background Art

[0002] Existing vital sign sensors usually use 60GHz millimeter wave radar technology and are designed for human respiratory heart rate perception and sleep assessment. It uses the FMCW (frequency modulated continuous wave) radar system, which can output the respiratory heart rate frequency of people in specific occasions, and combine it with long-term sleep posture and body movement collection to timely report the sleep status and history of people. The maximum distance of human presence detection of this millimeter wave radar is about 2.5 meters, and the maximum distance of human respiratory rate detection is about 1.5 meters. Limited by the sensing range of the radar, it is necessary to ensure that the radar is installed within 1.5 meters of the human chest to ensure normal detection of the radar. Generally, the height difference between the radar installation position and the bed surface is about 0.9 meters, and the error does not exceed 0.2 meters. The radar is tilted at an angle of 30° to 45° and is located above the head of the bed. The sensing distance of the radar greatly limits its sensing range, so that it can only monitor the vital signs of the elderly when they are sleeping or lying in bed. Summary of the invention

[0003] The purpose of the present invention is to provide an indoor vital sign sensing device and a sensing method based on SLAM technology, aiming to solve the problem of small detection range of existing vital sign sensors.

[0004] The present invention is implemented as follows: an indoor vital sign sensing device based on SLAM technology includes a SLAM mobile detection vehicle placed on the ground and a positioning radar structure installed on the wall. The positioning radar structure communicates with the SLAM mobile detection vehicle. The SLAM mobile detection vehicle is provided with a laser radar for scanning the surrounding environment, an odometer for obtaining the distance and direction information of an object, and an inertial measurement unit for measuring the acceleration and angular velocity of the vehicle.

[0005] A further technical solution of the present invention is: the positioning radar structure includes a fixed plate, a first shell, a connecting plate, a rotary servo and a swing servo, the fixed plate is installed on the wall, the rotary servo and the swing servo are arranged on the fixed plate, one end of the connecting plate is connected to the first shell, the rotary servo is connected to the swing servo, the other end of the connecting plate is connected to the swing servo, the rotary servo controls the first shell to rotate 360 ​​degrees, and the swing servo controls the first shell to swing 180 degrees up and down.

[0006] A further technical solution of the present invention is: a first millimeter-wave radar and a communication module are provided inside the first shell, the first millimeter-wave radar is connected to the communication module, the communication module communicates with the SLAM mobile detection vehicle, and the first millimeter-wave radar transmits 24GHz electromagnetic waves to the target and receives its echo.

[0007] A further technical solution of the present invention is: the azimuth angle range of the static coverage angle of the first millimeter-wave radar is ±60°, and the elevation angle range is ±35°.

[0008] A further technical solution of the present invention is: an indicator light is also provided in the first housing, and the indicator light is connected to the first millimeter-wave radar.

[0009] A further technical solution of the present invention is: the SLAM mobile detection vehicle includes a base, a first mounting plate, a second mounting plate, a third mounting plate, a fourth mounting plate and a main control board, the first mounting plate is connected to the top of the base through a first bracket, the second mounting plate is connected to the top of the first mounting plate through a second bracket, the third mounting plate is connected to the top of the second mounting plate through a third bracket, and the fourth mounting plate is connected to the top of the third mounting plate through a fourth bracket. The odometer is arranged on the base, the inertial measurement unit is arranged between the first mounting plate and the base, the main control board is arranged on the top of the second mounting plate, and the laser radar is arranged on the top of the fourth mounting plate. The laser radar, odometer and inertial measurement unit all communicate with the main control board.

[0010] A further technical solution of the present invention is: a second shell is provided on the third mounting plate, a second millimeter-wave radar and a communication chip are provided in the second shell, and the communication chip communicates with the communication module.

[0011] A further technical solution of the present invention is: a battery box is provided between the base and the first mounting plate.

[0012] Another object of the present invention is to provide a sensing method of an indoor vital sign sensing device based on SLAM technology, comprising the following steps: Step S1: The main control board of the SLAM mobile detection vehicle is connected to the communication module of the first millimeter-wave radar through the built-in WIFI module. The communication module transmits the distance, angle and speed information of the target human body to the main control board. The main control board uses the ROS system to establish nodes through simultaneous positioning and map building technology, and communicates with the laser radar, odometer and inertial measurement unit. The laser radar scans the surrounding environment to obtain the distance and direction information of the object. The inertial measurement unit measures the acceleration and angular velocity information of the vehicle. The main control board fuses and processes these data, extracts environmental features, and uses the Bayesian filtering method for probabilistic positioning. Combined with the laser radar, odometer and inertial measurement unit sensor data and motion model, the position of the detection vehicle in the map is estimated, and path planning is performed at the same time to calculate the optimal path between the detection vehicle position and the human target position, and in the process of driving, the path is optimized in real time according to the changes in the surrounding environment and the values ​​returned by the first millimeter-wave radar; Step S2: After the SLAM mobile detection vehicle reaches the predetermined position range using the SLAM algorithm, the second millimeter wave radar starts working and transmits millimeter wave signals through the antenna array. These signals are sent into space and form a beam through the directivity of the antenna. The shape and direction of the beam are controlled by adjusting the phase and amplitude of the antenna. When the transmitted millimeter wave signal encounters the target object, part of the signal is reflected back by the target object. The main control board receives these reflected signals and converts them into electrical signals. After amplification and filtering, the received millimeter wave signal enters the signal processing unit, analyzes the received signal, extracts the target information, and processes and distinguishes it; Step S3: The second millimeter-wave radar detects the weak signal reflected by the human body, processes the signal, determines the presence of the human body, and determines the duration of the human body's breathing micro-movement. When the presence of the human body is detected but there is no micro-movement breathing, it communicates with the main control board in time through the communication chip, and the main control board issues an alarm message.

[0013] The beneficial effects of the present invention are: through SLAM simultaneous positioning and mapping technology, the path is automatically calculated, obstacles are automatically avoided and the vehicle is driven to the vicinity of the monitored target. The millimeter-wave radar on the vehicle activates the vital signs of the monitored object, realizes accurate monitoring of vital signs, and promptly issues an alarm for dangers occurring in the ward, thereby ensuring the safety of the monitored object. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the installation of the device of the present invention; Figure 2 It is an overall diagram of the positioning radar structure of the present invention; Figure 3 It is an overall diagram of the SLAM mobile detection vehicle of the present invention.

[0015] Figure markings: 1-positioning radar structure, 2-SLAM mobile detection vehicle, 101-fixed plate, 102-rotating servo, 103-swinging servo, 104-connecting plate, 105-first shell, 106-first millimeter-wave radar, 107-communication module, 108-indicator light, 201-base, 202-odometer, 203-inertial measurement unit, 204-first mounting plate, 205-first bracket, 206-second mounting plate, 207-second bracket, 208-battery box, 209-lower computer single-chip microcomputer, 210-main control board, 211-third bracket, 212-third mounting plate, 213-fourth mounting plate, 214-fourth bracket, 215-second shell, 216-second millimeter-wave radar, 217-communication chip, 218-laser radar. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "bottom surface" and "top surface", "inside" and "outside" refer to directions toward or away from the geometric center of a specific component, respectively.

[0017] The present invention provides an indoor vital sign sensing device based on SLAM technology, comprising a SLAM mobile detection vehicle 2 placed on the ground and a positioning radar structure 1 installed on the wall. The positioning radar structure 1 communicates with the SLAM mobile detection vehicle 2. The SLAM mobile detection vehicle 2 is provided with a laser radar 218 for scanning the surrounding environment, an odometer 202 for obtaining distance and direction information of an object, and an inertial measurement unit 203 for measuring the acceleration and angular velocity of the vehicle.

[0018] Preferably, the positioning radar structure 1 includes a fixed plate 101, a first shell 105, a connecting plate 104, a rotary servo 102 and a swing servo 103, the fixed plate 101 is installed on the wall, the rotary servo 102 and the swing servo 103 are arranged on the fixed plate 101, one end of the connecting plate 104 is connected to the first shell 105, the rotary servo 102 is connected to the swing servo 103, and the other end of the connecting plate 104 is connected to the swing servo 103, the rotary servo 102 controls the first shell 105 to rotate 360 ​​degrees, and the swing servo 103 controls the first shell 105 to swing 180 degrees up and down.

[0019] Preferably, a first millimeter-wave radar 106 and a communication module 107 are provided inside the first shell 105, the first millimeter-wave radar 106 is connected to the communication module 107, the communication module 107 communicates with the SLAM mobile detection vehicle 2, and the first millimeter-wave radar 106 transmits 24 GHz electromagnetic waves to the target and receives its echo.

[0020] Preferably, the static coverage angle of the first millimeter-wave radar 106 has an azimuth angle range of ±60° and an elevation angle range of ±35°.

[0021] Preferably, an indicator light 108 is further provided in the first housing 105 , and the indicator light 108 is connected to the first millimeter-wave radar 106 .

[0022] Preferably, the SLAM mobile detection vehicle 2 includes a base 201, a first mounting plate 204, a second mounting plate 206, a third mounting plate 212, a fourth mounting plate 213 and a main control board 210, the first mounting plate 204 is connected to the top of the base 201 through a first bracket 205, the second mounting plate 206 is connected to the top of the first mounting plate 204 through a second bracket 207, the third mounting plate 212 is connected to the top of the second mounting plate 206 through a third bracket 211, the fourth mounting plate 213 is connected to the top of the third mounting plate 212 through a fourth bracket 214, the odometer 202 is arranged on the base 201, the inertial measurement unit 203 is arranged between the first mounting plate 204 and the base 201, the main control board 210 is arranged on the top of the second mounting plate 206, the laser radar 218 is arranged on the top of the fourth mounting plate 213, and the laser radar 218, the odometer 202 and the inertial measurement unit 203 all communicate with the main control board 210.

[0023] Preferably, a second shell 215 is provided on the third mounting plate 212 , and a second millimeter-wave radar 216 and a communication chip 217 are provided in the second shell 215 , and the communication chip 217 communicates with the communication module 107 .

[0024] Preferably, a battery box 208 is further provided between the base 201 and the first mounting plate 204 .

[0025] The present invention also provides a sensing method of an indoor vital sign sensing device based on SLAM technology, comprising the following steps: Step S1: The main control board 210 of the SLAM mobile detection vehicle 2 is connected to the communication module 107 of the first millimeter wave radar 106 through its own WIFI module. The communication module 107 transmits the distance, angle and speed information of the target human body to the main control board 210. The main control board 210 uses the simultaneous positioning and map building technology to establish a node using the ROS system, and communicates with the laser radar 218, the odometer 202 and the inertial measurement unit 203. The laser radar 218 scans the surrounding environment to obtain the distance and direction information of the object, and the inertial measurement unit 203 measures the acceleration and angular velocity information of the vehicle, and the main control board 210 fuses and processes these data, extracts environmental features, uses the Bayesian filtering method for probabilistic positioning, combines the laser radar 218, the odometer 202 and the inertial measurement unit 203 sensor data and motion model, estimates the position of the detection vehicle in the map, and performs path planning at the same time, calculates the optimal path between the detection vehicle position and the human target position, and during the driving process, optimizes the path in real time according to the changes in the surrounding environment and the values ​​returned by the first millimeter wave radar 106; Step S2: After the SLAM mobile detection vehicle 2 reaches the predetermined position range using the SLAM algorithm, the second millimeter wave radar 216 starts working and transmits millimeter wave signals through the antenna array. These signals are sent into space and form a beam through the directivity of the antenna. The shape and direction of the beam are controlled by adjusting the phase and amplitude of the antenna. When the transmitted millimeter wave signal encounters the target object, part of the signal is reflected back by the target object. The main control board 210 receives these reflected signals and converts them into electrical signals. After amplification and filtering, the received millimeter wave signal enters the signal processing unit, analyzes the received signal, extracts the target information, and processes and distinguishes it. Step S3: The second millimeter-wave radar 216 detects the weak signal reflected by the human body, processes the signal, determines the presence of the human body, and determines the duration of the human body's breathing micro-movement. When the presence of the human body is detected but there is no micro-movement breathing, it communicates with the main control board 210 in time through the communication chip 217, and the main control board 210 issues an alarm message.

[0026] The present invention provides an indoor vital sign sensing device and sensing method based on SLAM technology. Ordinary vital sign monitoring devices rely on a single millimeter wave radar to monitor human body movements such as breathing to judge human vital signs. Due to the detection distance and accuracy limitations of the millimeter wave radar, its coverage is small and its accuracy is low, which cannot fully meet the needs of full-range monitoring of hospital and nursing home wards. The indoor vital sign sensing device based on SLAM technology uses a 24GHz millimeter wave radar to detect and cover the ward monitoring area over a large range, and timely sends the indoor position of mentally disabled children or elderly people. After receiving the position of the target person, the SLAM mobile detection vehicle 2 automatically calculates the path through the SLAM simultaneous positioning and mapping technology, automatically avoids obstacles and drives to the vicinity of the monitoring target. The 60GHz millimeter wave radar on the vehicle starts the vital signs of the monitored object, realizes accurate monitoring of vital signs, and timely issues an alarm for the dangers of mentally disabled children or elderly people in the ward, thereby ensuring the safety of the monitored object.

[0027] The device consists of a positioning radar structure 1 and a SLAM mobile detection vehicle 2. The 24GHz motion positioning radar module can realize real-time tracking of the position of the moving target in the detection area, and output the distance, angle and speed information of the moving target in the area through the serial port. The information is transmitted to the SLAM mobile detection vehicle 2 through the communication module. The detection vehicle obtains the real-time position through the 2D laser radar 218 above it, and moves to the human body area through the SLAM algorithm. Automatic obstacle avoidance and path planning can be achieved during the movement. After reaching the target area, the 60GHz millimeter wave radar will be activated to scan the human body information in the area and sense the human heartbeat, so as to achieve the purpose of barrier-free and large-scale accurate monitoring of human vital signs.

[0028] In the positioning radar structure 1, the rotary servo 102 is installed on the fixed plate 101, and the fixed plate 101 is installed parallel to the wall. The rotary servo 102 is responsible for rotating the radar 360 degrees. The first housing 105 is connected to the swing servo 103 through the connecting plate 104. The swing servo 103 can swing the radar up and down 180 degrees, so as to achieve the purpose of covering the entire room. The static coverage angle of the first millimeter wave radar 106 is ±60° in azimuth and ±35° in pitch, with a maximum sensing distance of 8m, a distance resolution of 0.75m, a ranging accuracy of 0.15m, an angle accuracy of 2° to 20°, and a data refresh rate of 10Hz. The first millimeter wave radar 106 emits electromagnetic waves in the 24GHz frequency band, which is a global radar operating frequency band specified by ISM. There is less interference when working in this frequency band. The 24GHz electromagnetic wave irradiates the target and receives its echo, thereby obtaining information such as the distance from the target to the electromagnetic wave emission point, the distance change rate (radial velocity), direction, altitude, etc. The information is transmitted to the SLAM mobile detection vehicle 2 through the communication module 107, and the mobile detection vehicle starts working according to the feedback information.

[0029] The main control board 210 of the SLAM mobile detection vehicle 2 has a built-in WIFI module, which connects to the communication module 107 of the first millimeter-wave radar 106 of 24GHz through the main network, and the communication module 107 transmits the distance, angle and speed information of the target human body to the main control board 210. The main control board 210 uses SLAM (Simultaneous Localization and Mapping), i.e., simultaneous positioning and map building technology, to establish a node using the ROS system, and communicates with the laser radar 218, the odometer 202 and the inertial measurement unit 203. The laser radar 218 can scan the surrounding environment and obtain the distance and direction information of the object. The inertial measurement unit 203 can measure the acceleration, angular velocity and other information of the vehicle. The main control board 210 will fuse and process these data, extract environmental features such as landmarks, walls, obstacles, etc., and use the Bayesian filtering method for probabilistic positioning, combining the laser radar 218, odometer 202 and inertial measurement unit 203 sensor data and motion model to estimate the position of the detection vehicle in the map. At the same time, path planning is performed to calculate the optimal path between the detection vehicle position and the human target position, and in the process of driving, according to the changes in the surrounding environment and the values ​​returned by the first 24GHz millimeter wave radar 106, the path is optimized in real time. After the detection vehicle reaches the predetermined position range using the SLAM algorithm, the second 60GHz millimeter wave radar 216 starts working. The second millimeter wave radar 216 transmits millimeter wave signals through the antenna array. These signals are sent into space and form a beam through the directivity of the antenna. The shape and direction of the beam can be controlled by adjusting the phase and amplitude of the antenna, thereby achieving accurate detection of the target. When the emitted millimeter wave signal encounters a target object, part of the signal will be reflected back by the target object. The receiver of the main control board 210 receives these reflected signals and converts them into electrical signals for subsequent processing and analysis. After amplification, filtering and other processing, the received millimeter wave signal enters the signal processing unit, which is in the lower computer single chip 209. The signal processing unit is mainly responsible for analyzing the received signal, extracting target information, and processing and distinguishing. The first millimeter wave radar 106 and the second millimeter wave radar 216 can detect the weak signal reflected by the human body. The radar processes the signal to determine whether the human body exists or not, and to determine the duration of the human body's micro-movement of breathing. When the presence of a human body is detected, but there is no micro-movement of breathing, the radar communicates with the main control in time through the communication chip 217, and the main control board 210 will issue an alarm message to notify medical staff or the elderly / patient's family members. The millimeter wave radar has the advantage of non-contact detection and has no negative impact on the detected human body. The communication chip 217 model can adopt ESP8266.

[0030] The device needs to go through sensor data collection, front-end odometer 202 estimation, back-end nonlinear optimization and mapping, in which the sensor data is collected and the back-end optimization is fed back through loop testing. Sensor data: mainly used to collect various types of raw data in the actual environment, including laser scanning data, video image data, point cloud data, etc. Odometer 202: mainly used to estimate the relative position of moving targets at different times, including the application of algorithms such as feature matching and direct registration. Back-end: mainly used to optimize the accumulated error caused by the visual odometer 202. Including the application of algorithms such as filters and graph optimization. Mapping: used for three-dimensional map construction. Loop detection: mainly used to eliminate spatial accumulated errors.

[0031] The SLAM workflow is as follows: after the sensor reads the data, the visual odometer 202 estimates the relative motion (Ego-motion) between two moments, the back-end processes the cumulative error of the visual odometer 202 estimation result, and the map is built based on the motion trajectory obtained by the front-end and back-end. The loop detection considers the images of the same scene at different moments and provides spatial constraints to eliminate the cumulative error.

[0032] ROS (Robot Operating System) is the most mainstream and widely used open source operating system for robots in the world. It can provide the services that an operating system should have, including hardware abstraction, low-level device control, implementation of common functions, inter-process messaging, and package management; it also provides tools and library functions for acquiring, compiling, writing, and running code across computers. It is a highly flexible software architecture for writing robot software programs, providing support for code reuse for robot research and development. ROS also supports a joint system similar to a code repository, which can also achieve engineering collaboration and release. From drivers to the latest algorithms to powerful developer tools, the primary goal of ROS is to provide a unified open source program framework for controlling robots in a variety of real-world and simulation environments.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An indoor vital sign sensing device based on SLAM technology, characterized in that: The SLAM mobile detection vehicle comprises a SLAM mobile detection vehicle placed on the ground and a positioning radar structure installed on the wall. The positioning radar structure communicates with the SLAM mobile detection vehicle. The SLAM mobile detection vehicle is provided with a laser radar for scanning the surrounding environment, an odometer for obtaining the distance and direction information of an object, and an inertial measurement unit for measuring the acceleration and angular velocity of the vehicle.

2. The indoor vital sign sensing device based on SLAM technology according to claim 1 is characterized in that: The positioning radar structure includes a fixed plate, a first shell, a connecting plate, a rotary servo and a swing servo. The fixed plate is installed on the wall, and the rotary servo and the swing servo are arranged on the fixed plate. One end of the connecting plate is connected to the first shell, and the rotary servo is connected to the swing servo. The other end of the connecting plate is connected to the swing servo. The rotary servo controls the first shell to rotate 360 ​​degrees, and the swing servo controls the first shell to swing 180 degrees up and down.

3. The indoor vital sign sensing device based on SLAM technology according to claim 2 is characterized in that: A first millimeter-wave radar and a communication module are provided inside the first shell. The first millimeter-wave radar is connected to the communication module. The communication module communicates with the SLAM mobile detection vehicle. The first millimeter-wave radar transmits 24 GHz electromagnetic waves to the target and receives its echo.

4. The indoor vital sign sensing device based on SLAM technology according to claim 3 is characterized in that: The static coverage angle of the first millimeter-wave radar has an azimuth angle range of ±60° and an elevation angle range of ±35°.

5. The indoor vital sign sensing device based on SLAM technology according to claim 2 is characterized in that: An indicator light is also provided in the first shell, and the indicator light is connected to the first millimeter-wave radar.

6. The indoor vital sign sensing device based on SLAM technology according to claim 3 is characterized in that: The SLAM mobile detection vehicle includes a base, a first mounting plate, a second mounting plate, a third mounting plate, a fourth mounting plate and a main control board. The first mounting plate is connected to the top of the base through a first bracket, the second mounting plate is connected to the top of the first mounting plate through a second bracket, the third mounting plate is connected to the top of the second mounting plate through a third bracket, and the fourth mounting plate is connected to the top of the third mounting plate through a fourth bracket. The odometer is arranged on the base, the inertial measurement unit is arranged between the first mounting plate and the base, the main control board is arranged on the top of the second mounting plate, and the laser radar is arranged on the top of the fourth mounting plate. The laser radar, odometer and inertial measurement unit all communicate with the main control board.

7. The indoor vital sign sensing device based on SLAM technology according to claim 6, characterized in that: A second shell is disposed on the third mounting plate, a second millimeter-wave radar and a communication chip are disposed in the second shell, and the communication chip communicates with the communication module.

8. The indoor vital sign sensing device based on SLAM technology according to claim 6, characterized in that: A battery box is also provided between the base and the first mounting plate.

9. A sensing method for an indoor vital sign sensing device based on SLAM technology as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: Step S1: The main control board of the SLAM mobile detection vehicle is connected to the communication module of the first millimeter-wave radar through the built-in WIFI module. The communication module transmits the distance, angle and speed information of the target human body to the main control board. The main control board uses the ROS system to establish nodes through simultaneous positioning and map building technology, and communicates with the laser radar, odometer and inertial measurement unit. The laser radar scans the surrounding environment to obtain the distance and direction information of the object. The inertial measurement unit measures the acceleration and angular velocity information of the vehicle. The main control board fuses and processes these data, extracts environmental features, and uses the Bayesian filtering method for probabilistic positioning. Combined with the laser radar, odometer and inertial measurement unit sensor data and motion model, the position of the detection vehicle in the map is estimated, and path planning is performed at the same time to calculate the optimal path between the detection vehicle position and the human target position, and in the process of driving, the path is optimized in real time according to the changes in the surrounding environment and the values ​​returned by the first millimeter-wave radar; Step S2: After the SLAM mobile detection vehicle reaches the predetermined position range using the SLAM algorithm, the second millimeter wave radar starts working and transmits millimeter wave signals through the antenna array. These signals are sent into space and form a beam through the directivity of the antenna. The shape and direction of the beam are controlled by adjusting the phase and amplitude of the antenna. When the transmitted millimeter wave signal encounters the target object, part of the signal is reflected back by the target object. The main control board receives these reflected signals and converts them into electrical signals. After amplification and filtering, the received millimeter wave signal enters the signal processing unit, analyzes the received signal, extracts the target information, and processes and distinguishes it; Step S3: The second millimeter-wave radar detects the weak signal reflected by the human body, processes the signal, determines the presence of the human body, and determines the duration of the human body's breathing micro-movement. When the presence of the human body is detected but there is no micro-movement breathing, it communicates with the main control board in time through the communication chip, and the main control board issues an alarm message.

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