Abstract:
The ionosphere causes delay of radio signals, and if not mitigated, it can be the
largest source of error in GNSS positioning and navigation. The ionospheric models
can be used to estimate these ionospheric errors and also used for satellite and receiver
inter-frequency bias estimation and Total Electron Content (TEC) calibrations.
Nowadays there are several empirical ionospheric TEC models. We evaluated accuracy
of a relatively new model developed at DLR (Deutsches Zentrum f ¨ur Luft-und
Raumfahrt), the Neustrelitz TEC Model (NTCM), by using the GPS receiver vTEC
data as a reference data for the year 2012 in asosa (10.05
0
N latitude and 34.5644
E
longitude), Ethiopian sector. For this study the mean vertical TEC data was used as
a reference data for the NTCM model validation. Then the GPS receiver TEC values
and the modeled TEC values were then compared by the help of MATLAB software
after plotting the two values. From daily, monthly and seasonal plots of the modeled
and observed TEC values the mean errors, root mean square errors and standard
deviation errors and correlation coefficients were used as statistical analysis of the
two values. By doing so We found that the model able to reproduce vTEC values
with a mean modeling error of 8.8TECU and STD error of 3.8 TECU. In addition to
this in all days, seasons and months of the year the model overestimates the observed
vTEC value and have low mean errors at about 15UT hours.