Design Of Ionospheric Digisonde Data Processing And Ionogram Parameter Measurement System

The ionospheric digisonde is a major conventional device to detect from ground to ionosphere,whose work principle is emitting high-frequency sweeping-frequency pulse wave upward vertically by the transmitter of digisonde,then receiving echo signals that ionosphere reflected by the receiver of digisonde in the same place and analyzing the time delay of echo signal to obtain the curves of reflection frequency and height,that is,ionogram.This lab independently designs and applies an ionospheric digisonde,whose detecting data of reflection frequency and height information is stored in large capacity disk by SBF and DIF formats.It requires particular software system to process and analyze the data obtained by digisonde.In order to facilitate the ionosphere researchers offline access and analysis ionogram,the ionospheric research work.Thus,it is very significant to independently design and develop a software with the ability of processing and analyzing data.This thesis designs and realizes a set of system of digisonde with ionospheric digisonde data processing and ionogram parameter measurement,whose main functions includes processing the obtained data by digisonde to get distinct and dependable ionogram,and measuring the parameter of f ionogram to get accurate ionosphere characteristic parameters.The system mainly consists of five modules,specifically,file format choice module,data reading module,frequency height diagram draft and display module,auxiliary function module and parameter measurement module.Firstly,the thesis introduces the relevant knowledge of ionosphere detection(which includes the overview,vertical detection methods and principles of ionosphere)and the measurement methods and principles of ionogram's characteristics parameter.Then it demonstrates the software and hardware system structure and operation principle of independently designed digisonde,based on which it confirms the basic functions of data processing and ionogram's parameter measurement system of digisonde.According to the basic functions and combining sophisticated data processing software at home and abroad,it analyzes the feasibility and demand on system and then confirms the development tools and languages.Secondly,it generally designs the system to confirm its overall design ideas and execute modular decomposition on system's functions to confirm its modules' structure and their functions.According to the modules' functions and three-layer construction mold applied by system design,it confirms system's framework showing every module's layer structure.Thirdly,it designs every functional module in detail,which includes every one's implement process and key technology.Data reading module applies memory-mapped file technology to realize data reading,during whose process multithreading technology is applied to avoid that user takes for the programs in the state of de-animation.The data transfer between data reading module and ionogram draft and display module applies observer mode and multithreading technology,which can maintain the high degree of data consistency.Ionogram draft applies GDI+ graphics technology,during whose process it applies double buffering technology to avoid image flicker.The experimental results show that the graphic display is distinct and stable.There are also the problems of flicker and instability for ionogram's parameter measurement module,it thus also applies double buffering technology and GDI+ graphics technology for tracing waveform of ionogram.Last but not least,the system,on the Windows platform,encodes every module based on development tool Visual Studio 2005 and development language C++.And also the system passes the test to realize the functions of reading two file formats SBF and DIF,displaying ionogram,and measuring the characteristics parameter of ionogram.The system,running stably,distinct and simple main interface,user-friendly,provides software tool for data analysis and study obtained by digisonde,avails ionosphere researchers to their researches,which holds a certain of practical value.