Design Of Non-Contact Respiratory Monitoring System Based On 24GHZ Doppler Radar

The life signal detection technology based on non-contact Doppler radar has the characteristics of non-contact,long-distance and penetration.It can be widely used in daily family monitoring,medical monitoring,disaster rescue search,special crowd monitoring and other scenarios.In this paper,a non-contact respiratory monitoring system based on 24 GHz doppler radar is designed.The key and difficult point of this system is to extract respiratory signal from radar echo signal with strong noise interference.In this paper,based on the data acquisition hardware design of the non-contact respiratory monitoring system of 24 GHz doppler radar,the least square ellipse fitting method is used to correct the radar data and the demodulation method based on the thoracic motion rate is used to effectively avoid the phase unwrapping problem.The experimental results in real environment show that the system can accurately measure the respiratory rate in a non-contact way without affecting the comfort of sleep.It is very suitable for sleep breathing monitoring in daily life.For the design of non-contact respiratory monitoring system of 24 GHz doppler radar,the work of this paper mainly includes the following aspects:(1)The paper designs the hardware system of non-contact doppler radar respiratory monitoring to lay a foundation for subsequent data collection.(2)The paper designs the data acquisition software system required by the non-contact doppler radar for respiratory monitoring,which sends the data collected by the doppler radar to the PC for storage and processing,so as to prepare for the subsequent data processing.(3)A contact breathing detection intelligent mask system based on the temperature sensor was designed as the reference system in this paper to verify the effectiveness of the non-contact breathing monitoring system.(4)The respiratory detection algorithm of the non-contact respiratory monitoring system is realized,and the system finally complete the accurate extraction of the actual respiratory frequency.It is different from the theoretical simulation-based verification method used in other people's work,this paper uses real data to verify the experimental results.The experimental results show that this system can accurately detect the respiratory frequency,and the average absolute error is as low as 0.33 bpm,which meets the requirements of daily family respiratory detection.At present,most of the articles are doing some theoretical simulation.Once their methods are applied to the actual application scenarios,the accuracy is greatly reduced;However,this paper can accurately extract the respiratory frequency based on the actual application scenarios,so it is of great practical significance to design and complete the respiratory monitoring system.