TEC Variation Analysis During Near Peak Solar Year Activity Over Indian Subcontinent

Earth’s atmospheric layers are subjected to continuous changes in near-earth space. Hence, the space weather needs to be investigated, and the most reliable method is using satellite system. Widely used technique is Global Positioning System (GPS) which is primarily designed for tracking and navigation. Ionosphere, one of the earth’s atmospheric layers which contains free electrons, is highly affected by space weather like solar flares, geomagnetic storms and seasons. Since the GPS satellite signal travels through the ionosphere, its propagation is affected, and signal gets delayed by plasma of free electron known as total electron content (TEC). TEC not only depends on space weather but also on geographic location, specially the low latitude region (23° above and below the equator). Indian subcontinent falls under this low latitude region, and hence, satellite system applications like precise positioning, navigation, tracking and satellite communication are affected. Hence to correct the GPS delay, accurate estimation of TEC is necessary. In this paper, TEC and rate of TEC (ROT) are calculated, and the variation of the TEC is analyzed. The ionospheric delay, TEC and ROT are calculated for GPS data received on March 10, 2013, from the dual-frequency GPS receiver of NovAtel make located in K L University, Guntur, India (Lat: 16.44° N/Long: 80.62° E). The analysis presented in this paper will help in precise estimation of composition of ionosphere which will improve navigational accuracy.