Method of operation of an omni-directional bi-radar device

Abstract

The application discloses an omnidirectional biological radar device and a working method thereof, wherein a FMCW radar is installed on a 360-degree rotating platform, and the high-speed rotating radar is used to simultaneously realize omnidirectional vital sign detection on multiple human targets. The rotating radar platform can not only realize the identification of the existence of people in the surrounding environment, but also estimate the relative angle between the initial position of the radar and the object by using the virtual SIMO (Simple Input Multiple Output) method, so as to finally realize the simultaneous detection of the full-dimensional vital signs of multiple human targets. The realization of the task has important application value for future search and rescue and vital sign detection.

Description

Technical Field

[0001] This invention relates to the field of bio-radar or radar-based life detection, and more specifically, to a method of operating an omnidirectional bio-radar device. Background Technology

[0002] Vital signs are crucial for determining normal human activity, and respiration and heartbeat are the most direct indicators reflecting these signs. Respiration and heartbeat detection are primarily divided into contact and non-contact methods. Non-contact detection is gaining increasing importance due to its advantages, such as protecting medical personnel from infection and enabling remote monitoring. Millimeter-wave radar, with its high precision, strong anti-interference capabilities, and good environmental adaptability, is finding increasing application in non-contact vital sign detection. In particular, a growing number of applications require the ability to simultaneously and rapidly detect vital signs of people in different locations. For example, in disaster relief scenarios, comprehensive and rapid non-contact detection is of great significance for search and rescue operations.

[0003] Currently, some technologies are available that can simultaneously detect vital signs in multiple targets. For example, SISO (Simple Input Simple Output) FMCW (Frequency Modulated Continuous Wave) radar uses a feed feedback method to adjust the beam scan for remote two-dimensional localization and vital sign monitoring of multiple targets. However, this method is limited by the structure of the SISO FMCW radar, with a field of view of only 120°, and the scanning method makes the radar structure design relatively complex. Another example is SIL (Self Injection Locked) Doppler radar, which can achieve multi-target localization and vital sign detection with an azimuth range of up to 140°, but its design is more complex and less portable. There is also camera-guided FMCW radar used to identify different areas of the body to optimize the region of interest for monitoring respiratory rate and heart rate, but this requires fusing camera and radar data, consuming more computing resources. Yet another example is multi-target detection of FMCW radar by moving on a sliding rail, but the large one-dimensional sliding rail limits its portability, and the radar's constant speed movement requires motion compensation in the algorithm processing. Summary of the Invention

[0004] The primary objective of this invention is to provide an omnidirectional bio-radar device that enables 360° all-around recognition of multiple human targets and detection of vital signs, with a simple physical structure, portability, and low algorithm complexity.

[0005] A further objective of this invention is to provide a method for operating an omnidirectional bio-radar device.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0007] An omnidirectional biological radar device includes an omnidirectional rotating base, a radar front-end unit, a radar signal processing unit, and a radar power supply unit, wherein:

[0008] The central axis of the omnidirectional rotating base moves in a 360° circular motion in the horizontal direction at a fixed angular velocity;

[0009] The radar front-end unit is fixedly connected to the central axis of the omnidirectional rotating base and rotates at the same angular velocity as the central axis of the omnidirectional rotating base. The radar front-end unit continuously transmits chirp signals at a fixed frame period, and the radiation range of the transmitted chirp signals covers the entire horizontal plane. The radar front-end unit receives the echo signals reflected by the target and processes them to obtain digital beat frequency signals.

[0010] The radar signal processing unit processes the digital beat frequency signal obtained by the radar front-end unit to acquire the distance, angle, respiration and heart rate information of all surrounding targets;

[0011] The radar power supply unit supplies power to the radar front-end unit and the radar signal processing unit through the omnidirectional rotating base.

[0012] Preferably, the radar front-end unit includes a transmitting antenna and a receiving antenna, wherein:

[0013] The transmitting antenna is located at the rotation center O of the omnidirectional rotating base. Tx The transmitting antenna and the rotation center O Tx The distance (ROT, radius of transmission) is 0. The receiving antenna and the transmitting antenna are placed on the same plane perpendicular to the horizontal direction. The receiving antenna and the rotation center O are... Tx The distance (ROR, radius of reception) is R. rx The receiving antenna and the transmitting antenna rotate 360° around the horizontal direction under the drive of the central axis of the rotating base.

[0014] Preferably, the radar front-end unit further includes a voltage-controlled oscillator (VCO), a power amplifier (PA), a 90° phase shifter, a mixer, a low-noise amplifier (LNA), a low-pass filter, and an analog-to-digital converter (ADC), wherein:

[0015] The voltage-controlled oscillator generates a chirped signal, which is then split into two paths. One path is amplified by the power amplifier and transmitted to the detection target via the transmitting antenna. The other path is processed by the 90° phase shifter and then enters the mixer.

[0016] The echo signal reflected by the target is received by the receiving antenna, first passed through the low-noise amplifier, then mixed with the chirped signal processed by the 90° phase shifter by the mixer, and the resulting mixed signal is filtered by the low-pass filter and sampled by the analog-to-digital converter to obtain the digital beat frequency signal.

[0017] A method for operating an omnidirectional bio-radar device, the method being applied to the aforementioned omnidirectional bio-radar device, the method comprising the following steps:

[0018] S1: The radar front-end unit rotates rapidly at a fixed angular velocity and continuously transmits chirped signals at a fixed frame period. The radiation range of the transmitted chirped signals covers the entire horizontal plane. The horizontal direction is divided into multiple non-overlapping sectors, and the reflected echo signals are obtained. After processing, digital beat frequency signals are obtained.

[0019] S2: Perform data preprocessing on the digital beat frequency signal obtained after processing by the radar front-end unit, including performing fast Fourier transform, generating range Doppler map, removing DC offset, and obtaining range profile (RPF) and phase matrix PM for each sector.

[0020] S3: Identify suspected targets in the surrounding environment and extract the distance and phase information of the suspected targets from the phase matrix;

[0021] S4: Utilize the identification information of the same target from multiple sectors when the radar front-end unit rotates to estimate the angle of the target in a specific sector;

[0022] S5: Determine the phase of the target and acquire information on the distance, angle, respiration, and heart rate of all surrounding targets.

[0023] Preferably, in step S1, the radar front-end unit rotates rapidly at a fixed angular velocity and continuously transmits chirped signals at a fixed frame period. The radiation range of the transmitted chirped signals covers the entire horizontal plane, and the horizontal direction is divided into multiple non-overlapping sectors, specifically:

[0024] The radar front-end unit operates at a fixed angular velocity ω. rot Rapid rotation at a fixed frame period T fr It continuously transmits chirped signals, and the radiation range of the transmitted chirped signals covers the entire horizontal plane. The horizontal direction is divided into Div non-overlapping sectors. Each sector transmits Fra frame signals, and each frame includes one chirped signal, wherein:

[0025]

[0026] Div is ω rot and T frThe integer obtained after matching ensures that the chirp signal of each sector can complete the detection of the target at the same position and at the same time interval in each rotation.

[0027] Preferably, the digital beat frequency signal in step S1 is represented as SIF. 1,1 SIF 2,1 ,…,SIF Div,Fra The digital beat frequency signal of the div-th sector and the fra-th frame can be represented as:

[0028]

[0029] In the formula, div = 1, 2, ..., Div; fra = 1, 2, ..., Fra; t is the fast time; τ is the slow time; f r This is the startup frequency; N_tar is the total number of targets in the current sector; n_tar is the nth target in the current sector; It is a digital beat frequency signal SIF div ,fra is the amplitude; c is the speed of light; k r It is the slope of the chirped sawtooth wave signal, calculated using the following formula:

[0030]

[0031] Among them, B r It is the effective sweep bandwidth of the radar, T ra It is the duration of the chirp signal;

[0032] This is the round-trip distance of the current sector signal, calculated using the following formula:

[0033]

[0034] in, It is the distance from the current sector's transmitted signal to the target n_tar; It is the distance between the radar and the current target when the chest moves to the position closest to the body; This indicates the instantaneous displacement of the chest.

[0035] Preferably, step S2 specifically includes the following steps:

[0036] S2.1: Remove the digital beat frequency signal SIF from the div-th sector and the fra-th frame. div,fra Ignoreable items Then, calculate SIF. div,fra The Fast Fourier Transform (FFT) is used to obtain the distance FFT of the chirp signal in the div-th sector and the fra-th frame:

[0037]

[0038] In the formula, T fr It is the frame period of the chirped signal; It is the amplitude of the beat frequency signal of the target n_tar in the div sector and the fra frame; It is the frequency of the beat frequency signal. It is the phase of the beat frequency signal, calculated using the following formula:

[0039]

[0040] S2.2: Generate a range-Doppler map, re-dividing the range FFT of all digital beat frequency signals into data groups corresponding to the identified sectors. Each chirped digital signal has N... s N sampling points s That is, the index of the range bin is mapped according to the speed of time to obtain the range Doppler map of each sector measurement;

[0041] S2.3: Remove static clutter:

[0042]

[0043] Obtain the digitized RPF for each sector div (N s ,Fra):

[0044]

[0045] In the formula, RPF div This represents the distance profile value for the div-th sector. It is the distance FFT sampling point data containing complex information in the fra frame of the div sector;

[0046] S2.4: Recover the unambiguous phase information, generate the phase matrix PM corresponding to the range profile, and perform a step-by-step analysis on the matrix RPF. div Phase information for each item is calculated using the following formula:

[0047]

[0048] Where, n s ∈[1,N s ]; real(·) represents the real part operation; imag(·) represents the imaginary part operation; Arctan is a special arctangent function defined as follows:

[0049]

[0050] Again The unambiguous phase information is calculated according to the following formula:

[0051]

[0052] where n s ∈ [1, N s - 1];

[0053] Write each calculated item in matrix form to obtain a phase matrix:

[0054]

[0055] Preferably, step S3 specifically includes the following steps:

[0056] S3.1: Sequentially select N c frames from the Fra frame. If N c <<Fra, then RPF div (N s , Fra) and PM div (N s , Fre) are simplified to:

[0057] <00所学知识对解决当前问题的帮助程度00270>where n c ∈ [1, N c is the frame number obtained by renumbering the N c frames sequentially selected from the Fra frame starting from 1;

[0059] S3.2: Select the column index of the target corresponding item from the matrix RPF div :

[0060]

[0061] In the formula, N max represents the n div value of the position of the element with the maximum absolute value in the n s th row of RPF c (N c , N s );

[0062] S3.3: Select the target phase and distance information from the phase matrix PM:

[0063] Substitute into PM div (N <00所学知识对解决当前问题的帮助程度00047>, Fra) to obtain That is, the phase corresponding to the target, while corresponds to the distance of the target.

[0064] Preferably, step S4 specifically includes the following steps:

[0065] S4.1: Calculate the receiving points of two adjacent sectors that identify the same target and the rotation center O when the receiving antenna rotates. Tx The angle θ between the lines chord The corresponding chord length l chord :

[0066]

[0067] S4.2: Calculate the estimated distance difference between the echoes from two adjacent sectors receiving the same human target, calculated from the phase difference of the echo signals received from adjacent sectors for the same target:

[0068]

[0069] in, and These are the n selected from two adjacent sectors. c The phase estimate of the frame, specifically the value, can be obtained from the PM. div (N s Select n of sector div in Fra) c The phase estimate of the frame;

[0070] S4.3: Calculate the angle θ of the human target tar That is, the echo from the receiving point and the signal from the receiving point to O. Tx The angle between the lines connecting them:

[0071]

[0072] S4.4: Repeat steps S4.1 to S4.3 to calculate all n in all sectors. c Frame angle θ tar .

[0073] Preferably, step S5 specifically includes the following steps:

[0074] S5.1: Perform pairwise difference operations on the phase elements selected in step S3.2 according to adjacent sectors, and group all adjacent phases whose operation results are lower than the preset threshold Th into one group. These phases correspond to the same target, and the final number of groups corresponds to the number of targets around the radar.

[0075] S5.2: Perform FFT operation on each phase of the phase group belonging to the same target, then calculate the signal-to-noise ratio (SNR), and take the phase value corresponding to the highest SNR value. As the phase of the human target, the phase corresponds to The distance to the human target;

[0076] S5.3: Input the selected phase information into two different bandpass filters, one for breathing (0.1-0.6Hz) and the other for heartbeat (0.8-2.5Hz), and separate and calculate the breathing and heart rate values ​​of the corresponding target. At the same time, the angle information of the same sector and frame number as the selected phase information calculated in step S4.3 is the angle of the target.

[0077] S5.4: Repeat steps S5.2 to S5.3 to calculate the distance, angle, breathing rate, and heart rate of all targets around the radar.

[0078] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0079] (1) Existing technologies have limited detection angles. This invention, through a rapidly rotating radar, can detect targets within a 360° range around the radar.

[0080] (2) Existing methods can generally only detect a single target using a radar; the present invention can detect multiple targets around the radar.

[0081] (3) Even if the existing technology can rotate 360°, it can only detect objects, but it is powerless to detect the breathing and heartbeat of human targets. This is because the detection of objects is only based on the distance dimension and combined with angle information, while breathing and heartbeat require strict phase alignment (i.e., the same time slot is used to scan the same position each time). In this invention, the radar rotates at a fixed angular velocity, dividing the horizontal plane into multiple non-overlapping sectors with the radar transmitting antenna as the center. Each sector sends a fixed number of chirped signals, thereby achieving phase alignment of each sector and enabling the detection of breathing and heartbeat signals.

[0082] (4) A single SISO radar cannot measure the angle of a target. This invention utilizes multiple sectors receiving the echo signal of the same human target during rotation, which is equivalent to having multiple receiving radars on the plane at the same time, achieving the operation effect of a SIMO (Simple Input Multiple Output) radar, thereby realizing the angle estimation of the target. Attached Figure Description

[0083] Figure 1 This is a schematic diagram of the omnidirectional bio-radar device of the present invention.

[0084] Figure 2 This is a schematic diagram of the working method of the omnidirectional bio-radar device of the present invention.

[0085] Figure 3 The distance Doppler map for each sector measurement provided for the embodiment.

[0086] Figure 4 The receiver echo and receiver-to-O provided in the embodiment Tx A diagram showing the angle between the lines connecting them. Detailed Implementation

[0087] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent.

[0088] To better illustrate this embodiment, some parts in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions;

[0089] It will be understood by those skilled in the art that certain well-known structures and their descriptions may be omitted in the accompanying drawings.

[0090] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0091] Example 1

[0092] An omnidirectional biological radar device, such as Figure 1 As shown, it includes an omnidirectional rotating base, a radar front-end unit, a radar signal processing unit, and a radar power supply unit, wherein:

[0093] The central axis of the omnidirectional rotating base moves in a 360° circular motion in the horizontal direction at a fixed angular velocity;

[0094] The radar front-end unit is fixedly connected to the central axis of the omnidirectional rotating base and rotates at the same angular velocity as the central axis of the omnidirectional rotating base. The radar front-end unit continuously transmits chirped signals at a fixed frame period, and the radiation range of the transmitted chirped signals covers the entire horizontal plane. The radar front-end unit receives the echo signals reflected by the target and processes them to obtain digital beat frequency signals.

[0095] The radar signal processing unit processes the digital beat frequency signal obtained by the radar front-end unit to acquire the distance, angle, respiration and heart rate information of all surrounding targets;

[0096] The radar power supply unit supplies power to the radar front-end unit and the radar signal processing unit through the omnidirectional rotating base.

[0097] This embodiment mounts the FMCW radar on a 360° rotating platform, enabling simultaneous omnidirectional vital sign detection of multiple human targets through high-speed rotation. This rotating radar platform not only identifies the presence of people in the surrounding environment but also uses the proposed virtual SIMO (Simple Input Multiple Output) method to estimate the relative angle between the radar's initial position and the object, ultimately achieving simultaneous omnidirectional vital sign detection of multiple human targets. The realization of this task may have significant application value for future search and rescue and vital sign detection.

[0098] Example 2

[0099] This embodiment, based on Embodiment 1, continues to disclose the following content:

[0100] The radar front-end unit includes a transmitting antenna and a receiving antenna, wherein:

[0101] The transmitting antenna is located at the rotation center O of the omnidirectional rotating base. Tx The transmitting antenna and the rotation center O Tx The distance between them is 0, the receiving antenna and the transmitting antenna are placed on the same plane perpendicular to the horizontal direction, and the receiving antenna and the rotation center O are... Tx The distance is R rx The receiving antenna and the transmitting antenna rotate 360° around the horizontal direction under the drive of the central axis of the rotating base.

[0102] The radar front-end unit also includes a voltage-controlled oscillator, a power amplifier, a 90° phase shifter, a mixer, a low-noise amplifier, a low-pass filter, and an analog-to-digital converter, wherein:

[0103] The voltage-controlled oscillator generates a chirped signal, which is then split into two paths. One path is amplified by the power amplifier and transmitted to the detection target via the transmitting antenna. The other path is processed by the 90° phase shifter and then enters the mixer.

[0104] The echo signal reflected by the target is received by the receiving antenna, first passed through the low-noise amplifier, then mixed with the chirped signal processed by the 90° phase shifter by the mixer, and the resulting mixed signal is filtered by the low-pass filter and sampled by the analog-to-digital converter to obtain the digital beat frequency signal.

[0105] Example 3

[0106] This embodiment provides a method for operating an omnidirectional biological radar device, such as... Figure 2 As shown, the working method is applied to the omnidirectional biological radar device described in Example 1 or Example 2, and the working method includes the following steps:

[0107] S1: The radar front-end unit rotates rapidly at a fixed angular velocity and continuously transmits chirped signals at a fixed frame period. The radiation range of the transmitted chirped signals covers the entire horizontal plane. The horizontal direction is divided into multiple non-overlapping sectors, and the reflected echo signals are obtained. After processing, digital beat frequency signals are obtained.

[0108] S2: Perform data preprocessing on the digital beat frequency signal obtained after processing by the radar front-end unit, including performing fast Fourier transform, generating range Doppler mapping, removing DC offset, and obtaining the range profile and phase matrix of each sector.

[0109] S3: Identify suspected targets in the surrounding environment and extract the distance and phase information of the suspected targets from the phase matrix;

[0110] S4: Utilize the identification information of the same target from multiple sectors when the radar front-end unit rotates to estimate the angle of the target in a specific sector;

[0111] S5: Determine the phase of the target and acquire information on the distance, angle, respiration, and heart rate of all surrounding targets.

[0112] In step S1, the radar front-end unit rotates rapidly at a fixed angular velocity and continuously transmits chirped signals at a fixed frame period. The radiation range of the transmitted chirped signals covers the entire horizontal plane, which is divided into multiple non-overlapping sectors in the horizontal direction, specifically:

[0113] The radar front-end unit operates at a fixed angular velocity ω. rot Rapid rotation at a fixed frame period T fr It continuously transmits chirped signals, and the radiation range of the transmitted chirped signals covers the entire horizontal plane. The horizontal direction is divided into Div non-overlapping sectors. Each sector transmits Fra frame signals, and each frame includes one chirped signal, wherein:

[0114]

[0115] Div is ω rot and T fr The integer obtained after matching ensures that the chirp signal of each sector can complete the detection of the target at the same position and at the same time interval in each rotation.

[0116] The digital beat frequency signal mentioned in step S1 is represented as SIF. 1,1 SIF 2,1 ,…,SIF Div,Fra The digital beat frequency signal of the div-th sector and the fra-th frame can be represented as:

[0117]

[0118] In the formula, div = 1, 2, ..., Div; fra = 1, 2, ..., Fra; t is fast time; τ is slow time; f r This is the startup frequency; N_tar is the total number of targets in the current sector; n_tar is the nth target in the current sector; It is a digital beat frequency signal SIF div ,fra is the amplitude; c is the speed of light; k r It is the slope of the chirped sawtooth wave signal, calculated using the following formula:

[0119]

[0120] Among them, B r It is the effective sweep bandwidth of the radar, T ra It is the duration of the chirp signal;

[0121] This is the round-trip distance of the current sector signal, calculated using the following formula:

[0122]

[0123] in, It is the distance from the current sector's transmitted signal to the target n_tar; It is the distance between the radar and the current target when the chest moves to the position closest to the body; This indicates the instantaneous displacement of the chest.

[0124] Step S2 specifically includes the following steps:

[0125] S2.1: Remove the digital beat frequency signal SIF from the div-th sector and the fra-th frame. div,fra Ignoreable items Then, calculate SIF. div,fra The Fast Fourier Transform (FFT) is used to obtain the distance FFT of the chirp signal in the div-th sector and the fra-th frame:

[0126]

[0127] In the formula, T fr It is the frame period of the chirped signal; It is the amplitude of the beat frequency signal of the target n_tar in the div sector and the fra frame; It is the frequency of the beat frequency signal. It is the phase of the beat frequency signal, calculated using the following formula:

[0128]

[0129] S2.2: Generate a range-Doppler map, re-dividing the range FFT of all digital beat frequency signals into data groups corresponding to the identified sectors. Each chirped digital signal has N... s N sampling points s That is, the index of the distance cell is mapped according to the speed of time to obtain the range Doppler map of each sector measurement, such as... Figure 3 As shown, Figure 3 Each large square (i.e., a group) represents the RPF of a sector;

[0130] S2.3: Remove static clutter:

[0131]

[0132] Obtain the digitized RPF for each sector div (N s ,Fra):

[0133]

[0134] In the formula, RPF div This represents the distance profile value for the div-th sector. It is the distance FFT sampling point data containing complex information in the fra frame of the div sector;

[0135] S2.4: Recover the unambiguous phase information, generate the phase matrix PM corresponding to the range profile, and perform a step-by-step analysis on the matrix RPF. div Phase information for each item is calculated using the following formula:

[0136]

[0137] Where, n s ∈[1,N s ]; real(·) represents the real part operation; imag(·) represents the imaginary part operation; Arctan is a special arctangent function defined as follows:

[0138]

[0139] Again The unambiguous phase information is calculated using the following formula:

[0140]

[0141] Where, n s ∈[1,N s -1];

[0142] Representing the calculated terms in matrix form, we obtain the phase matrix:

[0143]

[0144] Step S3 specifically includes the following steps:

[0145] S3.1: Sequentially select N c frames from the Fra frame. If N c <<Fra, then RPF div (N s , Fra) and PM div (N s , Fre) are simplified to:

[0146]

[0147] where n c ∈ [1, N c is the frame number obtained by renumbering the N c frames sequentially selected from the Fra frame starting from 1;

[0148] S3.2: Select the column index of the target corresponding item from the matrix RPF div :

[0149] [[ID=Z40]]

[0150] In the formula, N max represents the n div (N s , N c ) in the position of the element with the maximum absolute value in the n c th row; [[ID=Z53]] s value;

[0151] S3.3: Select the target phase and distance information from the phase matrix PM:

[0152] Substitute into PM div (N s , Fra), and obtain which is the phase corresponding to the target, while [[ID=Z69]] corresponds to the distance of the target.

[0153] Step S4 specifically includes the following steps:

[0154] S4.1: Calculate the chord length l Tx corresponding to the included angle θ chord between the connecting lines of the receiving points of two adjacent sectors that identify the same target when the receiving antenna rotates and the rotation center O chord , as shown in Figure 4 . θ chord corresponds to each sector, that is, a complete rotation contains Div θs It should be noted that there may be some inaccuracies in the translation due to the complexity and potential ambiguity of the original text, especially in the context of patent - specific technical terms. If possible, it is recommended to cross - reference with the original language's patent documentation and relevant technical knowledge for a more accurate understanding.chord Taking one sector as an example, the receiving points A, B, and O in adjacent sectors... Tx The sector formed corresponds to the chord length, which is the length of line segment AB.

[0155]

[0156] S4.2: Calculate the estimated distance difference between the echoes from two adjacent sector receiving points that have detected the same human target. Figure 4 In the diagram, line segment AD is sector AO. Tx B and sector BO Tx The estimated value of the echo distance difference C can be calculated from the phase difference of the echo signals received from adjacent sectors for the same target.

[0157]

[0158] in, and These are the n selected from two adjacent sectors. c The phase estimate of the frame, specifically the value, can be obtained from the PM. div (N s Select n of sector div in Fra) c The phase estimate of the frame;

[0159] S4.3: Calculate the angle θ of the human target tar That is, the echo from the receiving point and the signal from the receiving point to O. Tx The angle between the lines connecting them, such as Figure 4 As shown:

[0160] θ tar With α i The following relationship exists:

[0161]

[0162] Where, α i That is, corresponding to Figure 4 Example sector ∠O Tx BD, and related:

[0163]

[0164] Where, β i That is, corresponding to Figure 4 The ∠ABD of the example sector has the following relationship:

[0165]

[0166] Then θ tar It can be represented as:

[0167]

[0168] S4.4: Repeat steps S4.1 to S4.3 to calculate all n in all sectors. c Frame angle θ tar .

[0169] Step S5 specifically includes the following steps:

[0170] S5.1: Perform pairwise difference operations on the phase elements selected in step S3.2 according to adjacent sectors, and group all adjacent phases whose operation results are lower than the preset threshold Th into one group. These phases correspond to the same target, and the final number of groups corresponds to the number of targets around the radar.

[0171] S5.2: Perform FFT operation on each phase of the phase group belonging to the same target, then calculate the signal-to-noise ratio, and take the phase value corresponding to the highest signal-to-noise ratio value. As the phase of the human target, the phase corresponds to The distance to the human target;

[0172] S5.3: Input the selected phase information into two different bandpass filters, one for breathing (0.1-0.6Hz) and the other for heartbeat (0.8-2.5Hz), and separate and calculate the breathing and heart rate values ​​of the corresponding target. At the same time, the angle information of the same sector and frame number as the selected phase information calculated in step S4.3 is the angle of the target.

[0173] S5.4: Repeat steps S5.2 to S5.3 to calculate the distance, angle, breathing rate, and heart rate of all targets around the radar.

[0174] The same or similar labels correspond to the same or similar parts;

[0175] The terms used to describe positional relationships in the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent.

[0176] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for operating an omnidirectional biological radar device, characterized in that, Includes the following steps: S1: The radar front-end unit rotates rapidly at a fixed angular velocity and continuously transmits chirped signals at a fixed frame period. The radiation range of the transmitted chirped signals covers the entire horizontal plane. The horizontal direction is divided into multiple non-overlapping sectors, and the reflected echo signals are obtained. After processing, digital beat frequency signals are obtained. S2: Perform data preprocessing on the digital beat frequency signal obtained after processing by the radar front-end unit, including performing fast Fourier transform, generating range Doppler mapping, removing DC offset, and obtaining the range profile and phase matrix of each sector. S3: Identify suspected targets in the surrounding environment and extract the distance and phase information of the suspected targets from the phase matrix; S4: Utilize the identification information of the same target from multiple sectors when the radar front-end unit rotates to estimate the angle of the target in a specific sector; S5: Determine the phase of the target and acquire information on the distance, angle, respiration, and heart rate of all surrounding targets; The digital beat frequency signal mentioned in step S1 is represented as SIF. 1,1 SIF 2,1 ,…,SIF Div,Fra The digital beat frequency signal of the div-th sector and the fra-th frame can be represented as: In the formula, div = 1, 2, ..., Div; fra = 1, 2, ..., Fra; t is fast time; τ is slow time; f r This is the startup frequency; N_tar is the total number of targets in the current sector; n_tar is the nth target in the current sector; It is a digital beat frequency signal SIF div ,fra is the amplitude; c is the speed of light; k r It is the slope of the chirped sawtooth wave signal, calculated using the following formula: Among them, B r It is the effective sweep bandwidth of the radar, T ra It is the duration of the chirp signal; This is the round-trip distance of the current sector signal, calculated using the following formula: in, It is the distance from the current sector's transmitted signal to the target n_tar; It is the distance between the radar and the current target when the chest moves to the position closest to the body; This indicates the instantaneous displacement of the chest.

2. The operating method of the omnidirectional biological radar device according to claim 1, characterized in that, In step S1, the radar front-end unit rotates rapidly at a fixed angular velocity and continuously transmits chirped signals at a fixed frame period. The radiation range of the transmitted chirped signals covers the entire horizontal plane, which is divided into multiple non-overlapping sectors in the horizontal direction, specifically: The radar front-end unit operates at a fixed angular velocity ω. rot Rapid rotation at a fixed frame period T fr It continuously transmits chirped signals, and the radiation range of the transmitted chirped signals covers the entire horizontal plane. The horizontal direction is divided into Div non-overlapping sectors. Each sector transmits Fra frame signals, and each frame includes one chirped signal, wherein: Div is ω rot and T fr The integer obtained after matching ensures that the chirp signal of each sector can complete the detection of the target at the same position and at the same time interval in each rotation.

3. The operating method of the omnidirectional biological radar device according to claim 2, characterized in that, Step S2 specifically includes the following steps: S2.1: Remove the digital beat frequency signal SIF from the div-th sector and the fra-th frame. div,fra Ignoreable items Then, calculate SIF. div,fra The Fast Fourier Transform (FFT) is used to obtain the distance FFT of the chirp signal in the div-th sector and the fra-th frame: In the formula, T fr It is the frame period of the chirped signal; It is the amplitude of the beat frequency signal of the target n_tar in the div sector and the fra frame; It is the frequency of the beat frequency signal. It is the phase of the beat frequency signal, calculated using the following formula: S2.2: Generate a range-Doppler map, re-dividing the range FFT of all digital beat frequency signals into data groups corresponding to the identified sectors. Each chirped digital signal has N... s N sampling points s That is, the index of the distance cell is mapped according to the speed of time to obtain the distance Doppler map of each sector measurement; S2.3: Remove static clutter: Obtain the digitized RPF for each sector div (N s ,Fra): In the formula, RPF div This represents the distance profile value for the div-th sector. It is the distance FFT sampling point data containing complex information in the fra frame of the div sector; S2.4: Recover the unambiguous phase information, generate the phase matrix PM corresponding to the range profile, and perform a step-by-step analysis on the matrix RPF. div Phase information for each item is calculated using the following formula: Where, n s ∈[1,N s ]; real(·) represents the real part operation; imag(·) represents the imaginary part operation; Arctan is a special arctangent function defined as follows: Again The unambiguous phase information is calculated using the following formula: Where, n s ∈[1,N s -1]; Representing the calculated terms in matrix form, we obtain the phase matrix:

4. The operating method of the omnidirectional biological radar device according to claim 3, characterized in that, Step S3 specifically includes the following steps: S3.1: Sequentially select N c frames from the Fra frame. If N c <<Fra, then RPF div (N s , Fra) and PM div (N s , Fra) are simplified to: Where, n c ∈[1,N c ] is N selected sequentially from Fra frames. c The frame number is obtained by re-numbering the frames starting from 1; S3.2: From matrix RPF div Select the column index corresponding to the target item: In the formula, N max Indicates RPF div (N s N c The nth in ) c The position of n where the absolute value of the element is the maximum s value; S3.3: Select target phase and range information from the phase matrix PM: Will Substitute into PM div (N s From Fra), we obtain That is, the phase corresponding to the target, and This corresponds to the distance to the target.

5. The operating method of the omnidirectional biological radar device according to claim 4, characterized in that, Step S4 specifically includes the following steps: S4.1: Calculate the receiving points of two adjacent sectors that identify the same target and the rotation center O when the receiving antenna rotates. Tx The angle θ between the lines chord The corresponding chord length l chord : S4.2: Calculate the estimated distance difference between the echoes from two adjacent sectors receiving the same human target, calculated from the phase difference of the echo signals received from adjacent sectors for the same target: in, and These are the n selected from two adjacent sectors. c The phase estimate of the frame, specifically the value, can be obtained from the PM. div (N s Select n of sector div in Fra) c The phase estimate of the frame; S4.3: Calculate the angle θ of the human target tar That is, the echo from the receiving point and the signal from the receiving point to O. Tx The angle between the lines connecting them: S4.4: Repeat steps S4.1 to S4.3 to calculate all n in all sectors. c Frame angle θ tar .

6. The operating method of the omnidirectional biological radar device according to claim 5, characterized in that, Step S5 specifically includes the following steps: S5.1: Perform pairwise difference operations on the phase elements selected in step S3.2 according to adjacent sectors, and group all adjacent phases whose operation results are lower than the preset threshold Th into one group. These phases correspond to the same target, and the final number of groups corresponds to the number of targets around the radar. S5.2: Perform FFT operation on each phase of the phase group belonging to the same target, then calculate the signal-to-noise ratio, and take the phase value corresponding to the highest signal-to-noise ratio value. As the phase of the human target, the phase corresponds to The distance to the human target; S5.3: Input the selected phase information into two different bandpass filters, one for breathing (0.1-0.6Hz) and the other for heartbeat (0.8-2.5Hz), and separate and calculate the breathing and heart rate values ​​of the corresponding target. At the same time, the angle information of the same sector and frame number as the selected phase information calculated in step S4.3 is the angle of the target. S5.4: Repeat steps S5.2 to S5.3 to calculate the distance, angle, breathing rate, and heart rate of all targets around the radar.

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