Impacts of Intense Geomagnetic Storms on NavIC / IRNSS System

Mehulkumar Desai,Shweta Shah

doi:10.4401/ag-7856

Abstract

The Total Electron Content (TEC) of Navigation with the Indian Constellation (NavIC)/ Indian Regional Navigation Satellite System (IRNSS) was examined under the influence of an intense geomagnetic storm occurred on 8 September, 2017, in the low latitudes of the Indian re- gion. One week (3 September, 2017 to 9 September, 2017) data from five stations located in the equatorial region and in the Equatorial Ionization Anomaly (EIA) area in India are collected from Accord NavIC/IRNSS dual-frequency (L5 and S-band) receivers for the investi- gation. The diurnal TEC comparison between IRI-2007 empirical model and NavIC/IRNSS dual frequency model is done. Through a com- parative study, of TEC at the five locations, we clearly observed geomagnetic storms using dual-frequency NavIC/IRNSS receivers, while the diurnal TEC behavior of the IRI-2017 model was the same on all observation days. On the intense stormy day, we observed an increase of about 19 TECU for the area near the equator and decrease of about 20 TECU in the EIA region compared to other observed quiet days. As a result, positive correlation between TEC and storm occurrence were found in the equatorial region, while a negative one in EIA re- gion. In order to support dramatic change in TEC during intense geomagnetic storm, geomagnetic indices and solar wind/IMF parameters maps are added. The results have been further validated using TEC map from IGS data and thermosphere O/N2 ratio map from Global UV Imager (GUVI).

Highlights

The regional Navigation with the Indian Constellation (NavIC)/Indian Regional Navigation Satellite System (IRNSS) system developed by the Indian Space Research Organization (ISRO) will use radio wave signals in L5 band (1164.45 to 1188.45 MHz) with a carrier frequency of 1176.45 MHz (F1) and S band (2483.5 to 1188.45 MHz) with a carrier frequency of 2492.08 MHz (F2), in order to provide accurate positioning anytime in India [Desai et al, 2018; 2017; 2016; ICD, 2011]
We investigated the impacts of intense geomagnetic storms beginning from September 08 2017 on newly emerging regional NavIC/ IRNSS systems
The paper shows the impact of intense geomagnetic storm (8 September, 2017) on NavIC/IRNSS system for the low latitudes of Indian region

Summary

INTRODUCTION

The regional Navigation with the Indian Constellation (NavIC)/Indian Regional Navigation Satellite System (IRNSS) system developed by the Indian Space Research Organization (ISRO) will use radio wave signals in L5 band (1164.45 to 1188.45 MHz) with a carrier frequency of 1176.45 MHz (F1) and S band (2483.5 to 1188.45 MHz) with a carrier frequency of 2492.08 MHz (F2), in order to provide accurate positioning anytime in India [Desai et al, 2018; 2017; 2016; ICD, 2011]. NavIC/IRNSS signals that propagated through the low latitude ionosphere are affected by the inhomogeneous, anisotropic, and dispersive nature of the ionosphere This characteristic can introduce unknown delay in the signals, which in turns cause a degradation of the positional accuracy of the NavIC/IRNSS system [Desai et al, 2018; 2015, Ruparelia et al, 2015]. The impact of the storm occurred as a positive increment in areas close to the equatorial region, while in the EIA area was negative The geomagnetic indices such as Dst(nT), AE(nT), Sym-H(nT), IMF-Bz(nT) and interplanetary parameters (Kp, Ap) were observed to verify the existence of intense storms on September 8, 2017. The observation is further validated by plotting a world TEC map after collecting the data in IONEX file format from International GNSS Service (IGS) and thermosphere O/N2 ratio map from online Thermosphere Ionosphere Mesosphere Energetic and Dynamics (TIMED) based Global Ultraviolet Imager (GUVI) site

GEOMAGNETIC PARAMETER ANALYSES AND DATA COLLECTION

Findings

DISCUSSION

CONCLUSION