Software Design And Research On Security Protection Technology Of Pulsar Digital Backend Based On ARM Embedded Platform

In the field of pulsar research,since the pulsar has the characteristics of linear polarization,short pulse,rotation stability and mass,the study of pulsars can be used to measure the magnetic field distribution of the Milky Way,to verify the general relativity,to study the electron density model of the Milky Way,to detect gravitational waves and to make interstellar navigation and so on.The pulsar digital backend system is a device that receives signals from pulsar radiation in real time and stores the observed data in real time at the storage terminal of the device for subsequent analysis and processing.This paper focuses on the software design of the pulsar digital backend based on ARM embedded platform developed by Southeast University,the software design of the backend control center and the security protection of the pulsar digital backend.Firstly,this paper introduces the research background of the subject,analyzes and studies the design idea and system architecture of the advanced pulsar digital backend platforms and the backend control centers at home and abroad as well as the security protection technology of the pulsar digital backend.Then,the whole architecture and the design of each unit of the pulsar digital backend based on ARM embedded platform are introduced,including VGA unit,ADC unit,clock unit,FPGA data processing unit and ARM control unit.The design has the characteristics of miniaturization,modularity and high flexibility,and can receive the target pulsar signal according to the required bandwidth and time/frequency resolution.Secondly,this paper realizes the software design and the software design of the control center of the pulsar digital backend based on the ARM embedded platform.The software design of the backend control center implements the user remote control based on the B/S architecture,realizes the remote control website by applying PHP dynamic website language and SQLite database technology,and realizes the asynchronous refresh of the website by applying AJAX technology.The object-oriented and multi-threaded technology C++ language is applyed to realize the software design of the database management unit,the hardware control unit,the logic control unit and the data storage unit of the pulsar digital backend.In addition,this paper realizes the security protection design of the pulsar digital backend based on embedded ARM platform.At first,the architecture of web server and embedded Linux system of the pulsar digital backend system is discussed,and the security threats faced by the system are analyzed.Then,aiming at the security threats,the HTTPS technology is applyed to realize that the embedded web server in the system can transmit data encrypted;The SSH Technology is applyed to realize that the system can be controlled remotely in the manner of encryption;The iptables technology is applyed to realize that the system is only allowed to transmit only the legitimate data.Finally,the function and performance of the pulsar digital backend system based on ARM embedded platform were tested,where field test was carried out at the Sheshan 65 meters observation station in Shanghai Observatory.The results show that the design of this paper meets the requirements of pulsar digital backend.