Ionospheric total electron content modelling and the estimation of errors in coordinate measuring caused by solar activity in remote sensing
2014
Devyatkin, Alexander | Gotur, Ivan | Krasnov, Valery | Kuleshov, Yury | Meshkov, Aleksey
The new procedure of ionospheric total electron content (TEC) modelling and prediction for the high-precision Global Navigation Satellite System applications is proposed and evaluated. To determine errors at coordinate measuring associated with solar activity influence on the ionosphere and, as consequence, on radio-wave propagation, the IRI2012 model has been adapted, and estimation of the solar activity index based on TEC measurement is used. Three initial conditions have been specified: (1) the calculated solar activity index does not depend on coordinates; (2) the method is based on the IRI2012 model, as this model is the most adequate one for the experiment; (3) measurement errors of the navigation signals and errors of the IRI2012 model are random ones; thus, the statistically mean values of the solar activity index have to be calculated. The equation for linear combination of satellite navigation observables is formulated to define the experimental ionospheric delay. This equation is supplemented with the expression including the TEC values for two different elevation angles along line from receiver to satellite. The calculated solar activity index (called FTEC) is determined on the basis of the experimental delay and model simulation values. Daily variation of the calculation error of the Belmopan_BLZ2012 station coordinates has been compared, using the correction of the ionospheric delays based on both the map proposed by the authors and TEC US-TEC map. The comparison has revealed the presence of approximately equal errors that are on the average equal to 5 m with the standard deviation up to ~1.8 m.
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