Study On Distributed Bio-radar System

Bio-radar is an emerging technology for non-contact detection of vital signs by combining radar,electronics,biomedical engineering,signal detection and processing technologies.Up to now,it has been widely used in many fields,such as natural disaster relief,non-contact medical monitoring,concealed monitoring during psychological testing,and safety monitoring.Bioradars have developed many systems,including ultra-wideband bioradars,continuous wave bioradars,and more.At present,there are some shortcomings in the single-channel bio-radar system.For example,the detection area is limited.Usually,a bio-radar can only cover a specified area,and the detection efficiency is limited.The data between bio-radars is uncorrelated,and multiple bio-radars cannot be processed uniformly if they work at the same time.As a result,the detection accuracy needs to be improved.If the detection fails,the error cannot be effectively corrected.However,the common multichannel bio-radar is separated and transmitted,and the detection strategy is limited.In order to improve these shortcomings,this paper designs and implements a wireless distributed bioradar system to improve detection range,accuracy,and portability.The main work and innovations of this paper are mainly composed of the following points:Firstly,the article analyzes the shortcomings of existing bio-radar technology,make out the requirements of the system,and designed the overall structure and network of wireless distributed bio-radar system by combining the distributed sensors technology.The system consists of terminal nodes,anchor nodes,and a host computer.It has good network communication performance,real-time processing performance,and excellent expansion performance.Second,according to the design of the system,the terminal nodes of the system are designed and implemented.The terminal node is composed of a bioradar sensor,a control module,a wireless network module,and a power source.The JC123-5.0UA2 continuous wave bioradar sensor developed by the research group is used as the front end.The axial detection distance is 10 meters and the horizontal azimuth angle is ±40°.The wireless communication module using Zigbee technology greatly expands the system detection range.The terminal node finally realized has good working performance and small size,only 104mm×48mm×45mm,which satisfies the system requirements.Third,the computer control software is designed in the.Net environment.The control software is mainly divided into data communication layer,data processing layer,data analysis layer and user interface display layer.The software uses the synchronous context transfer protocol to solve the conflict between the display thread and other threads.The object-oriented programming idea is used to instantiate each terminal node into independent individuals,which improves the scalability of the system.And the variable length fast Fourier transform analysis methods extract the displayed human respiratory frequency in real time,and the overall PC software interface is intuitive and the function is well realized.Forth,based on the distributed bio-radar system,the system performance was tested and the wireless network node location research was carried out.According to the characteristics of the distributed bio-radar system,the multi-biological radar detection in the actual environment,the same-frequency interference experiment,the experiment of the human body posture toward the detection of respiratory signals and the single bio-radar detection and multi-biological radar detection Comparative Experiment are carried out.The data fusion technology of multi-biological radar on the same area simultaneous overlapping detection strategy is studied.The experimental results show that under the experimental conditions of this paper,the average detection error of the distributed bio-radar system when detecting respiratory signals is 3.02 times/min,4.54 times/min,4.99 times/min and 2.56 times/min,which are smaller than the result that average error during detection was 6.64 beats/min when using single bioradar.After data fusion,the detection error was reduced to 2.96 beats/min.In summary,the distributed bio-radar system designed and implemented in this paper has better detection effect,simple structure,light weight,good portability and expandability,intuitive software interface.As well as the detection results,it shows good performance.