CN-116047502-B - Animal vital sign monitoring method and system based on microwave beam regulation and control

CN116047502BCN 116047502 BCN116047502 BCN 116047502BCN-116047502-B

Abstract

The invention provides an animal vital sign monitoring method and system based on microwave beam regulation, comprising a positioning step of detecting and positioning sensitive parts of target respiration and heartbeat in a visual field range based on a band-pass filter bank, a phase shift control step of constructing a phase encoding matrix and performing phase shift control on transmitting signals of transmitting antennas so that synthesized beams of the transmitting antennas face the sensitive parts obtained by positioning, a signal transceiving step of acquiring a plurality of echo signals and performing signal processing to obtain a multichannel baseband signal, and a demodulation step of performing micro-motion phase demodulation on the multichannel baseband signal to extract vital sign information of the target. The invention can process the multichannel baseband signals through the band-pass filter group to realize detection and positioning of the respiratory heartbeat sensitive part of the animal, and can detect the vital signs of the animal through the methods of phase coding and beam focusing to improve the testing distance, the signal-to-noise ratio and the measuring precision.

Inventors

XIONG YUYONG
PENG ZHIKE
LI SONGXU

Assignees

上海交通大学

Dates

Publication Date: 20260512
Application Date: 20221219

Claims (6)

1. An animal vital sign monitoring method based on microwave beam regulation and control, which is characterized by comprising the following steps: The positioning step is to detect and position the sensitive parts of target respiration and heartbeat in the visual field range based on the band-pass filter bank; A phase shift control step of constructing a phase encoding matrix, and performing phase shift control on the transmitting signals of the transmitting antennas so that the synthesized wave beams of the transmitting antennas face the sensitive part obtained by positioning; A signal receiving and transmitting step, namely acquiring a plurality of echo signals and performing signal processing to obtain a multichannel baseband signal; The demodulation step is that micro-motion phase demodulation is carried out on the multichannel baseband signal, and vital sign information of a target is extracted; the positioning step comprises the following steps: step 1.1, transmitting and receiving microwave signals to obtain multichannel microwave baseband signals Wherein i represents the ith sweep period, N is the number of equivalent receiving channels output by millimeter wave front end, and the baseband signal of the nth receiving channel M is the total sampling point number of a single channel in a sweep frequency period; Step 1.2, obtaining heat map information of microwave baseband signals of each sweep frequency period, and obtaining position information of each target in a view field range; Step 1.3, performing band-pass filtering on the heat map information in a plurality of sweep frequency periods by using a band-pass filter bank, wherein the first passband of the band-pass filter bank is The second passband is Obtaining angle information of sensitive parts of animal respiration and heartbeat from the filtered heat map ; The demodulation step includes: Step 4.1, extracting a micro-motion displacement time sequence of the sensitive part of each scanning period caused by respiration and heartbeat through micro-motion phase demodulation: In the formula, The angle denoted as beam scan is The emission sweep frequency period is The displacement sequence element value of the respiratory heartbeat sensitive part of the detected animal with the distance R; a sweep frequency period of the linear frequency modulation continuous wave is transmitted for the transmitting antenna; n is the number of single-channel baseband signal elements in each sweep period, N is the serial number of single-channel baseband signal elements in each sweep period; Sampling frequency time for the baseband signal; Scanning the beam at an angle of First, the Matrix composed of M channel baseband signals in each emission sweep frequency period, and column vector of matrix is the first Baseband signals of the channels; Is an imaginary unit; the beat frequency estimation value is corresponding to the measured object or measuring point distance; the distances from the mth receive antenna to the first receive antenna, m=1.. M, wherein ; The wavelength is the wavelength corresponding to the center frequency of the linear frequency modulation continuous wave; And 4.2, processing the micro-motion displacement time sequence including fast Fourier transform to acquire vital sign information including respiratory and heartbeat frequencies.
2. The method for monitoring animal vital signs based on microwave beam regulation of claim 1, wherein the phase shift control step comprises: step 2.1, according to the angle information Constructing a phase coding matrix: Where d k , k=2,..k, the distance of the kth transmit antenna from the first transmit antenna, K the number of transmit antennas, The wavelength is the wavelength corresponding to the center frequency of the linear frequency modulation continuous wave; the initial phase of each transmitting antenna is set to 0 according to the phase encoding matrix, ,..., ; Step 2.2, controlling each antenna to simultaneously transmit microwave signals, so that the main lobe direction angle of the synthesized wave beam is Towards sensitive parts of the breath and heartbeat of the animal to be tested.
3. The method for monitoring animal vital signs based on microwave beam regulation according to claim 2, wherein the step of receiving and transmitting signals comprises: and controlling a plurality of transmitting antennas to simultaneously transmit linear frequency modulation continuous wave signals, enabling a main lobe of the synthesized wave beam to face the sensitive part of the target, receiving echo signals of the target by utilizing a plurality of receiving antennas, and obtaining a multichannel microwave baseband signal after hardware mixing and low-pass filtering.
4. The method for monitoring animal vital signs based on microwave beam regulation of claim 1, further comprising: and a beam scanning step, namely returning to a phase shift control step after the demodulation step, and directing the synthesized beam to the sensitive part of the next target obtained by positioning and continuing to monitor.
5. An animal vital sign monitoring system based on microwave beam regulation, comprising: A microwave signal transceiver for transmitting a multichannel linear frequency modulation continuous wave microwave signal, receiving a return wave signal, and outputting a multichannel baseband signal; The target detection and positioning module is used for processing the multichannel baseband signals to obtain heat map information, and detecting and positioning target respiration and heartbeat sensitive parts in the view field range based on the band-pass filter bank; The beam scanning control processing module is used for constructing a phase encoding matrix, carrying out phase shift control on the transmitting signals of the transmitting antennas, enabling the synthesized beams of the transmitting antennas to face the sensitive part obtained by positioning, carrying out micro-motion phase demodulation on the multichannel baseband signals, and extracting vital sign information of a target; The target detection positioning module transmits and receives microwave signals to obtain multichannel microwave baseband signals Wherein i represents the ith sweep period, N is the number of equivalent receiving channels output by millimeter wave front end, and the baseband signal of the nth receiving channel M is the total sampling point number of a single channel in one sweep frequency period, the heat map information of a microwave baseband signal of each sweep frequency period is obtained to obtain the position information of each target in the view field range, the heat map information in a plurality of sweep frequency periods is subjected to band-pass filtering by using a band-pass filter bank, wherein the first passband of the band-pass filter bank is that The second passband is Obtaining angle information of sensitive parts of animal respiration and heartbeat from the filtered heat map ; The beam scanning control processing module extracts micro-motion displacement time sequences of sensitive parts of each scanning period caused by respiration and heartbeat through micro-motion phase demodulation: In the formula, The angle denoted as beam scan is The emission sweep frequency period is The displacement sequence element value of the respiratory heartbeat sensitive part of the detected animal with the distance R; a sweep frequency period of the linear frequency modulation continuous wave is transmitted for the transmitting antenna; n is the number of single-channel baseband signal elements in each sweep period, N is the serial number of single-channel baseband signal elements in each sweep period; Sampling frequency time for the baseband signal; Scanning the beam at an angle of First, the Matrix composed of M channel baseband signals in each emission sweep frequency period, and column vector of matrix is the first Baseband signals of the channels; Is an imaginary unit; the beat frequency estimation value is corresponding to the measured object or measuring point distance; the distances from the mth receive antenna to the first receive antenna, m=1.. M, wherein ; The wavelength is the wavelength corresponding to the center frequency of the linear frequency modulation continuous wave; and processing the micro-motion displacement time sequence including fast Fourier transformation to acquire vital sign information including respiratory and heartbeat frequencies.
6. The animal vital sign monitoring system based on microwave beam regulation of claim 5, wherein the beam scanning control processing module is configured to control the beam scanning based on the angle information Constructing a phase coding matrix: Where d k , k=2,..k, the distance of the kth transmit antenna from the first transmit antenna, K the number of transmit antennas, The wavelength is the wavelength corresponding to the center frequency of the linear frequency modulation continuous wave; the initial phase of each transmitting antenna is set to 0 according to the phase encoding matrix, ,..., ; Controlling each antenna to simultaneously emit microwave signals to make the main lobe direction angle of the synthesized wave beam be Towards the animal to be tested.

Description

Animal vital sign monitoring method and system based on microwave beam regulation and control Technical Field The invention relates to vital sign monitoring technology, in particular to an animal vital sign monitoring method and system based on microwave beam regulation. Background During daily production, life, scientific research and work, vital sign monitoring of animals is often required. For example, in the raising process of livestock such as cattle and sheep, abnormal conditions of livestock bodies are monitored in time, mortality is reduced, vital signs of wild animals are monitored, counted and analyzed in observation, research and protection work of the wild animals, and vital sign monitoring is carried out in animal experiments in a laboratory, so that scientific research is completed. The existing vital sign monitoring methods are mostly measured by means of contact, for example by mounting contact sensors on the animal body and then transmitting data by radio. The installation of such sensors presents a certain risk, in particular for monitoring wild animals, while such contact sensors can affect the comfort of the animal itself and thus the measurement results. Therefore, how to realize remote, non-contact, portable and accurate vital sign monitoring has important research significance. In recent years, people have started to monitor vital signs of human bodies by using a microwave sensing method, but the existing vital sign monitoring based on microwave sensing needs that the human bodies keep a quasi-static state, and a microwave radar aims at the chest position, so that the sensitive parts of respiration and heartbeat monitoring are difficult to accurately locate under the condition of long distance. In summary, the existing microwave sensing method has a great limitation in animal remote non-contact vital sign monitoring. Disclosure of Invention Aiming at the defects in the prior art, the invention aims to provide an animal vital sign monitoring method and system based on microwave beam regulation. The invention provides an animal vital sign monitoring method based on microwave beam regulation, which comprises the following steps: The positioning step is to detect and position the sensitive parts of target respiration and heartbeat in the visual field range based on the band-pass filter bank; A phase shift control step of constructing a phase encoding matrix, and performing phase shift control on the transmitting signals of the transmitting antennas so that the synthesized wave beams of the transmitting antennas face the sensitive part obtained by positioning; A signal receiving and transmitting step, namely acquiring a plurality of echo signals and performing signal processing to obtain a multichannel baseband signal; And a demodulation step of performing micro-motion phase demodulation on the multichannel baseband signal and extracting vital sign information of a target. Preferably, the positioning step includes: Step 1.1, transmitting and receiving microwave signals to obtain a multi-channel microwave baseband signal BS i＝[S1,S2,…,SN, wherein i represents an ith sweep period, N is the number of equivalent receiving channels output by a millimeter wave front end, baseband signals S n = [ S (1, N), S (2, N) ], M is the total sampling point number of a single channel in one sweep period; Step 1.2, obtaining heat map information of microwave baseband signals of each sweep frequency period, and obtaining position information of each target in a view field range; Step 1.3, performing band-pass filtering on the heat map information in a plurality of sweep frequency periods by using a band-pass filter bank, wherein the first passband of the band-pass filter bank is The second passband isAngle information θ q (q=1, 2) of sensitive parts of animal respiration and heartbeat is obtained from the filtered heat map. Preferably, the phase shift control step includes: Step 2.1, constructing a phase encoding matrix according to the angle information theta q: Wherein d k (k=2,..k) is the distance of the kth transmitting antenna from the first transmitting antenna, K is the number of transmitting antennas, λ c is the wavelength corresponding to the center frequency of the chirped continuous wave; Setting the initial phase of each transmitting antenna to be 0,2 pi d 2sinθq/λc,…,2πdK sinθq/λc respectively according to the phase coding matrix; And 2.2, controlling each antenna to simultaneously emit microwave signals, so that the main lobe direction angle of the synthesized beam is theta q and faces the animal to be detected. Preferably, the signal transceiving step includes: and controlling a plurality of transmitting antennas to simultaneously transmit linear frequency modulation continuous wave signals, enabling a main lobe of the synthesized wave beam to face the sensitive part of the target, receiving echo signals of the target by utilizing a plurality of receiving antennas, and obtaining a multichannel