GPS Data Receiving Software And Primary Analysis Of Ionospheric TEC In Xiamen

Theionosphereisanameforthelayeroftheearth's atmospherethatisionizedbysolar radiation, and is also an important part of near-ground space which plays animportant role in our every-day life because of its influence on the passage of radiowaves.Theexistenceoftheequatorialanomalymakesthemidandlow-latitudinalareaquite important district in ionospheric research. The crests of the equatorial anomalyare near 20°in magnetic latitude, and ionospheric scintillation mainlyappears in thisdistricts.Sotheresearchonmidandlow-latitudinalionosphereisconcerned.A GPS-Ionosphere observation site was set up in Xiamen (118°6'E, 24°28'N)Center for Space Science and Applied Research, Chinese Academy of Sciences toresearchionosphereofmidandlow-latitude.Xiamenis locatednearthenorthcrest ofthe equatorial anomaly, and the research on ionosphere above Xiamen plays asignificant role in further recognizing ionospheric physics and making sure thepositioning and navigation system run normally. Based on the observation site, themaintopicsandresultsofthestudyinthisdissertationareasfollows:First, analysed the software named GPSClient, written in Visucal C++, andimproveditsfunctionsbyaddingandmodifyingitssourcefiles.Second, improved another software named GPSTool which was also written inVisucal C++, to pretreat nearly two years'GPS data acquired by GPSClient, nearly35G,andTECdataat1-sintervalareobtainedandsavedinnewfiles.Third, a program was written in Interactive Data Language (IDL) to visualizeTEC data in figures. Intensity of TEC from August 26th,2005 is present in thisdissertation.Fourth, according the figures, diurnal variation, monthly variation and variationwith seasons of TEC were analyzed. The variation of diurnal TEC maximum withdays is also used to acquire the characteristics of ionosphere at Xiamen. The resultsareasfollows:TECbecomesmaximuminAutumnandSpring,anditcouldbe~70TECU,itcould be lower in winter, about 40TECU. When summer comes, TEC becomes minimum,maximumofTECinsummeralwayslowerthan30TECU;The time corresponding to the maximum TEC of one day vary irregularly ,especially during the half year from February to August. It is even later two hoursthanexperiencevalue--14LT.ThesamephenomenonisobservedinTaiwan.