Ionospheric Gradients Estimation and Analysis of S-Band Navigation Signals for NAVIC System

Navigation with Indian constellation (NAVIC) is the operational name given to the Indian Regional Navigation Satellite System developed by the Indian Space Research Organisation, India. The most influential factor is ionospheric gradients that can degrade the positional accuracy of the global navigation satellite system users especially in low-latitude regions. The main aim of this paper is to estimate the ionospheric gradient variations obtained from the NAVIC receiver located at Guntur, India (16.23° N, 80.44° E). Code and carrier phase measurements of S-band (2492.028 MHz) signals are used to derive ionospheric time delays and total electron content (TEC) values. In this paper, S-band signals of NAVIC are used for the first time to investigate ionospheric gradients over low-latitude region. The recursive least squares (RLS) algorithm is implemented as a single frequency ionospheric model for estimating the absolute TEC, and longitudinal (E–W) and latitudinal (N–S) ionospheric gradients. Ionospheric gradient analysis has been carried for three consecutive days during September equinox, December solstice in 2016, and for a geomagnetic disturbed event observed during May 2017. The annual statistical analysis in the periodic structure of spatial ionospheric gradients from NAVIC S-band signals during June 2016–May 2017 is also discussed. It is evident that RLS model can estimate ionospheric gradients for a single NAVIC station. The outcome of this work would be useful for understanding ionospheric irregularities climatology over low-latitude region.

[1]  Simon Haykin,et al.  Adaptive Filter Theory 4th Edition , 2002 .

[2]  Jean-Luc Issler,et al.  Estimating the Ionospheric Delay Using GPS/Galileo Signals in the E5 Band , 2013 .

[3]  Win Zaw Hein,et al.  Estimation Method of Ionospheric TEC Distribution using Single Frequency Measurements of GPS Signals , 2016 .

[4]  Juan Blanch,et al.  Robust Detection of Ionospheric Irregularities , 2000 .

[5]  Peter Steigenberger,et al.  IRNSS Orbit Determination and Broadcast Ephemeris Assessment , 2015 .

[6]  Sanjay Kumar,et al.  Morphology of equatorial plasma bubbles during low and high solar activity years over Indian sector , 2017 .

[7]  N. Arslan,et al.  The impact of temporal ionospheric gradients in Northern Europe on relative GPS positioning , 2008 .

[8]  J. Klobuchar.  Ionospheric Time-Delay Algorithm for Single-Frequency GPS Users , 1987, IEEE Transactions on Aerospace and Electronic Systems.

[9]  A. S. Ganeshan,et al.  BENEFITS OF INDIAN SATELLITE NAVIGATION SYSTEMS , 2017 .

[10]  D. Venkata Ratnam,et al.  Ionospheric Spatial Gradient Detector Based on GLRT Using GNSS Observations , 2016, IEEE Geoscience and Remote Sensing Letters.

[11]  Takayuki Yoshihara,et al.  An Investigation of Local-Scale Spatial Gradient of Ionospheric Delay Using the Nation-Wide GPS Network Data in Japan , 2005 .

[12]  Philip J. Erickson,et al.  A strong positive phase of ionospheric storms observed by the Millstone Hill incoherent scatter radar and global GPS network , 2005 .

[13]  Mohammed Mainul Hoque,et al.  Mitigation of higher order ionospheric effects on GNSS users in Europe , 2008 .

[14]  Abhijeet Dasgupta,et al.  Equatorial scintillations in relation to the development of ionization anomaly , 2006 .

[15]  A. D. Sarma,et al.  Investigation of the Effect of Ionospheric Gradients on GPS Signals in the Context of Laas , 2014 .

[16]  S. Haykin,et al.  Adaptive Filter Theory , 1986 .

[17]  Jamila Beckheinrich,et al.  Mitigation of the Ionospheric Range Error in single-frequency and single-station GNSS applications , 2008 .

[18]  D. Venkata Ratnam,et al.  Performance evaluation of selected ionospheric delay models during geomagnetic storm conditions in low‐latitude region , 2011 .

[19]  Ljiljana R. Cander,et al.  Large scale ionospheric gradients over Europe observed in October 2003 , 2008 .

[20]  Mardina Abdullah,et al.  Detection of plasma bubble in ionosphere using GPS receivers in Southeast Asia , 2017 .

[21]  J. Foster,et al.  A quantitative study of ionospheric density gradients at midlatitudes , 2001 .

[22]  A. Gupta,et al.  Latitude variation of total electron content in the equatorial region , 1967 .

[23]  IsIdre mAteu.  A search for spectrum : GNss signals in s-band Part 1 , .