Design And Implementation Of Rescue Terminal Software Based On NB-IoT And BDS

With the development of economy and the improvement of people's living standard,more and more people are interested in hiking and involved in operating in the wild,which leads to an increase in the number of people in distress.At present,field communication terminals such as mobile phones,satellite phones,and walkie-talkies have problems of low communication reliability,insufficient battery life and lack of personalized service for the wild scene due to limited communication signal coverage,large power consumption,and no vital signs detection function.When people are in danger in the wild,they are more likely to be rescued if they can send out a distress signal in time and accurately report their location.Therefore,it is of a great value to develop a field rescue terminal with reliable communication and strong battery life.The main research work of this thesis is the design and implementation of the rescue terminal software.To start with,through the demand analysis and assessment of the rescue terminal software,the comparative study of the mainstream Internet of Things wireless communication technology and location technology,Narrow Band Internet of Things(NB-IoT)is used as the main communication technology while BD? is used as the terminal positioning and auxiliary transmission technology in this thesis.To meet the needs of low cost,low power consumption and small size of the terminal,the hardware design scheme based on the ATSAMD20J18 A microcontroller as the main control is selected and the terminal software runs on the microcontroller chip.Next,the functions and performance requirements of terminal software such as data sending and receiving,power consumption control and dual-mode communication are analyzed and studied in detail.The deficiencies of the current software design scheme are optimized,and the software system design scheme is designed for the terminal hardware platform in this thesis.Based on the design scheme of software system,research and design the detailed process of terminal data sending process,terminal data receiving process,dual-mode communication switching control based on NB-IoT and short message,low power dynamic process groups scheduling based on the working mode of each hardware module and software implementation process.Then,ATSAMD20J18 A MCU is programmed and integrated with the terminal hardware.Finally,a test and verification platform consisting of system platform,NB-IoT network,Bei Dou network,and rescue terminal prototype was built.The results reveal that the rescue terminal software designed in this thesis can realize the business functions of data collection and analysis,accurate positioning,distress signal sending by pressing the button,information reporting and fault indication.The success rate of dual-mode communication switching between NB-IoT and short message reached 97.33%,and the success rate of communication between rescue terminal and platform reached more than 95%.Terminal equipment can work for about 7 days in normal working and standby mode.