Research On Monitoring Techniques Of Group Physiological Parameters In The Aircraft Cabin Environment

With the increase of age,the physical function of people begins to decline after entering middle age,and the probability of suffering from various diseases increases dramatically.In addition,due to unhealthy diets,middle-aged and elderly people have become a high-risk group of cardiovascular diseases,and they are more sensitive to some unusual environments.The aircraft cabin is a typical low-pressure environment,so it has great significance to monitor the physiological parameters related to cardiovascular function of cabin passengers.Existing wearable physiological parameter monitoring,which is often short-term,decentralized,and unsystematic,is not suitable for long-term continuous monitoring during flight.Moreover,the power supply scheme with Li-ion battery used by most devices does not comply with aviation safety regulations.Based on photoplethysmography(PPG),this dissertation designs a system for monitoring the physiological parameters of group passengers in aircraft cabin,and this system is able to reliably and quickly collect,preserve and analyze the raw data,and timely feedback detection result to the user.The research on this system can not only prevent accidents of oxygen deficiency caused by reduced air pressure or apnea,but also provide the test basis for passengers’ heart health through big data,providing the source of data for detecting and preventing cardiovascular diseases in special circumstances.A set of human physiological parameter monitoring device suitable for the aircraft cabin environment is developed.The device uses a neck pillow as a carrier,collecting PPG signals from the ear lobe of the passenger using an ear-clip blood oxygen probe with 660 nm red light and 940 nm infrared light as light source,and reasonably arranging power supply and related hardware which is convenient for passengers to wear and use under the premise of meeting aviation regulations.The hardware system uses oversampling techniques to improve the accuracy of the Analog-to-Digital Converter(ADC),and saves the accumulated sampled values of the ADC as a complete raw sampled signal without averaging,which can reduce the amount of calculations without losing sampling accuracy.A cloud server-based physiological parameter storage,analysis and feedback system is developed.The two-way upload data mechanism is adopted to allow the server to receive and store the raw monitoring data transmitted by the mobile terminal or the monitoring device,which satisfies the requirement for the integrity and timeliness of the raw data.An efficient algorithm for extracting human physiological parameters from the PPG signals is designed.The extracted parameters include heart rate,heart rate variability,breathing rate and blood oxygen saturation.The difference between the PPG signals of the two light sources is used for calculating physiological parameters except blood oxygen saturation,which effectively suppresses the motion interference and retains the respiratory drift information required for extracting the respiratory signal.The oxygen saturation is calculated using the ratio of the average heights of the two signals to make the calculations more stable.Finally,the physiological parameters obtained by the analysis are sent to the end users in the form of detection report.The detection report is generated by a complete health assessment mechanism that can achieve health tracking of individual user and health comparisons between different users.A mobile terminal application system is developed.This application can communicate with the monitoring device through the user’s mobile terminal by using Bluetooth technology,and realize functions such as controlling the working state of the monitoring device,viewing the monitoring data in real time,and saving the raw monitoring data.It can also communicate with the cloud server through the network to realize functions such as user registration,uploading raw monitoring data,viewing history record,downloading detection report and replaying monitoring process.A communication solution is developed between monitoring device and mobile terminals and cloud servers.Among them,the Bluetooth communication protocol is proposed to realize communication and data exchange between the monitoring device and the mobile terminal.The solution for connecting by QR code corresponding to a Bluetooth MAC address of a terminal application scanning monitoring device is proposed by analyzing the problem that in a small environment it is difficult to find the connected device when Bluetooth of multiple devices are turned on at the same time.The Wireless Local Area Network protocol is used to realize communication and data exchange between the cloud server and the terminal device,and between the monitoring device and the cloud server.After experimental verification,the monitoring system can reliably upload data,quickly analyze and feedback detection reports,and the detected user heart rate and blood oxygen saturation data are accurate and reliable.The developed health assessment mechanism can effectively reflect changes in the user’s physiological parameters.