PREDICTION OF IONOSPHERIC ERROR IN GPS DATA AT AN OBSERVATION STATION

Abstract

Space-based radio navigation systems such as the Naystar Global Positioning System (GPS) can provide us with a unique opportunity to study the effect of the ionosphere as the signals propagate from the satellites to the GPS receivers. The ionosphere affects the electromagnetic waves that pass through it by inducing an ad-ditional transmission time delay. The ionosphere influence has now become the largest error source in GPS positioning and navigation. This dissertation involves the determination of total electron content (TEC) in ionosphere in order to predict the error value. The ionospheric model used is the modified single layer model used on the Bernese GPS 5.0 Software. The ionosphere TEC maps are obtained for year 2011 at an interval of 2 hrs. Data displaying the solar activity is considered as a parameter in predicting the error. Results show that the ionospheric variation is different relative to the solar activity and produce more error. These variations play an important role in understanding the ionosphere and thus will simplify the studies about phenomenon happen in ionosphere. The impact of the TEC values for Bangalore region is described based on the location of IGS receiver. The TEC values for a whole year were obtained and their variation is analyzed with respect to the solar activity. The determination of TEC values is done using the Bernese GPS software. The positioning error is calculated depending on the TEC values and its relationship with the solar flux is obtained in order to predict the values for the December month. Keywords: Ionosphere, Total Electron Content (TEC), Bernese software, Global Positioning System (GPS) Page