Development Of A Refrigerated Container Monitoring Terminal Based On Low-orbit Satellite Communications And Cellular Mobile Communications

As the rapid demand of the cold chain transportation,the refrigerated container transportation business will expand day by day,and the security problems occurred in the course of transport will be brought to the attention of the people,so it seems significant to realize the remote monitoring for the reefer container.However,the most of existing total solution to realize the remote monitoring of refrigerated containers are based on the cable network communication and the cellular mobile communication to solve the problem of remote data transmission.Because of some factors,such as distribution of base stations,signal interface and so on,it is unable to realize remote data transmission in the remote and pelagic areas.In this paper,it is put forward a solution,based on combining the satellite communications technology and the cellular communications technology,to solve the remote monitoring of reefer containers around the world without blind zone.In this paper,the development of refrigerated container monitoring terminal uses embedded technology,GPS positioning technology,serial communication technology,Leo satellite communication technology and cellular mobile communication technology,etc.It uses STM32 process as CPU,gets location information with GPS positioning module,and gets the cold machine messages with RS232 serial port,and the external sensor module provides state information of refrigerated container.It uses satellite module or cellular module to send packets,eventually transmits packets to the back-end data center,so as to realize remote monitoring of reefer container.In this paper,it is designed the hardware circuit principle diagram of the power management module,GPS module,cold machine data acquisition module,the external sensor module,cellular module and satellite module;Based on ?C/OS-II real-time operating system,and using C/C++ to complete the program of GPS location data acquisition,cold machine data acquisition,external sensor data acquisition,cellular communications,satellite communications and so on.Besides,it is set the reefer monitoring terminal functional testingplatform,to test the prototype's hardware testing and software debugging,functional test,reliability test,and so on.The prototype is verified the function of positioning,cold machine data acquisition,cellular mobile communication,satellite communication under normal environment and the specific environment.Moreover,the prototype is installed in the reefer,and the result shows that the prototype function is normal,and satisfies the requirement of development.In this paper,the development of reefer containers terminals are advantageous to make the cold chain transportation equipment to be a more intelligent monitor,and provides a technical solution to achieve the globalization of the refrigerated container transportation monitoring;In addition,it reserves several interfaces used to further expand and improve the function of containers terminals.