Application And Research Of Software Radio On Ionosonde

Ionospheric physics is considered as an exploratory science. Observations havebeen playing an important role in the ionospheric research. It has been shown fromthe ionospheric science development that new sounding techniques or methodsalways promote the development of ionospheric physics research, at the same time,the ionospheric physics research also requires more new sounding techniques andmethods. In the history of nearly 80 years' development of ionospheric probing, radiowave sounding has always occupied a very important position. The development ofradio technology, microelectronics and computer science, which promote thedevelopment of ionospheric radio sounding techniques, make a great contribution tothe ionospheric sounding research.Ionosonde, as a routine instrument, has one of main method on ionosphericmonitoring and scientific research. Nowadays, there are still about 200 stations basedon ionospheric vertical sounding working hour after hour in the world. Ionosondetechniques have been developed continuously. Early manual, analog ionosonde hasbecome automatic, digital instrument. In the 1990s', the potable digital ionosondewhich can be connect-ted into the net has become true.At the beginning of new 21 century, people have paid more and more attentionon space weather including ionosphere, so demands on means of ionosphericmonitoring have been expanded. Ionosonde, as a basic instrument, also need todevelop and be perfect. Under this background, and getting benefit from WuhanIonospheric Station of using digisonde in long time, we present a conception fordeveloping a new software digital ionosonde. This new sounding system with flexible,advanced, and powerful, could change software to complete developing new probingmode. In this paper we describe the design of the system hardware architecture bycombining software radio idea with ionospheric vertical sounding techniques, the manufacture of the platform for data collection and preprocessing, and the debuggingof the system.The main work in this paper are as follow:1) Introduce the conception, research status, hardware realization, theoreticfoundation of software radio.2) Recount the development of modern digital ionosonde and its key techniques,combine software radio idea with ionospheric vertical sounding techniques, present aconception for developing a new software digital ionosonde, and discuss in detailsabout the system architecture, feature and feasibility. It demonstrates that the theoryand technique are mature for developing new software ionospheric soundingnowadays, and it would satisfy the demands of ionospheric space weather research in21 century.3) According to the scheme frame, the detailed platform for data collection andforeclosing of receiver's digital unit is designed. Using IF sampling technique, highspeed ADC(AD6644), DDC(GC4016), PCI bus, and microcomputer, the platform isembodied. The experiment results can verify practical circuit's functions, such as IFsampling, the detectable imputing range, quadrature digital mixing, samplesdecimation, and digital filtering. The results attest the validity of designed schemepractically.We only do some research in data collecting and processing. Of course, we willmeet many questions what should be resolved later. We hope that our works could laythe foundations for realization of the new software digital ionosonde system andapplication of software radio in ionospheric radio sounding.