Statistical Comparison of Various Interpolation Algorithms for Grid-Based Single Shell Ionospheric Model Over Indian Region

Abstract

Future Satellite Based Navigation Systems based on GPS, like US Wide Area Augmentation Sysytem (WAAS), are of global interest to the scientific community. Precise estimation of ionospheric delay is most crucial for successful implementation of the systems. Due to the complex ionospheric structure and large variation of Total Electron Content (TEC) in low latitudes, it is necessary to compare and validate the efficiency of the existing algorithms in this region. In this study, performances of the various interpolation algorithms for TEC calculation at ionospheric grid point (IGP) and user position for gridbased Single Shell Model have been tested for 72 test days of 2005. Based on the results obtained from this analysis, it has been found that, for the Indian region, it would be more suitable to use Ordinary Kriging in place of Planar Fit to estimate delay at an IGP (as used by US WAAS). It has also been found that Ordinary Kriging performs better than the Bilinear Interpolation technique at the user end.

Modeling of Ionospheric Time Delay Using Anisotropic IDW With Jackknife Technique

“…PROMINENT EXISTING IONOSPHERIC TIME-DELAY MODELS Because of the complex structure and dynamic nature of the ionosphere, the performances of the models are not uniform, especially at equatorial and low-latitude regions. The suitability and performance of ionospheric delay models can vary when implemented globally, regionally, and locally [13]. In view of this, for comparison and evaluation of the proposed anisotropic IDW with Jackknife technique, three prominent models, namely, Kriging, spline, and MPF, are considered.…”

Approach for near‐real‐time prediction of ionospheric delay using Klobuchar‐like coefficients for Indian region

“…There are several ionospheric models currently being studied and developed. Out of these, the main models are the grid-based single-shell model [2][3][4], the two-shell model [5] and the Klobuchar model [6]. The Klobuchar model is a simplistic empirical model and is currently being utilised by the GPS users for correcting the ionospheric delay.…”

“…Flow chart of prediction methodology www.ietdl.org STEC is obtained. The detailed description of pre-processing of the TEC is provided by Shukla et al[4,5].…”

Effect of Grid Size Variation on the Interpolation of the Total Electron Content over the Indian Region

“…Other techniques like Kriging are also proposed for the next generation of WAAS [10][11][12]. Shukla et al [9] in their study have found that both at the IGP and the user side, Ordinary Kriging is more suitable for the Indian region among the various algorithms tested. On the basis of the results from their study, two combinations have been considered to reconstruct the Slant Total Electron Content (STEC) for the present analysis.…”

“…For single-frequency users of GPS, the ionosphere is the largest source of error in estimation of user position. Due to the presence of the Equatorial Ionospheric Anomaly (EIA) over the Indian region [7], the Planar Fit, which is currently used by WAAS [8], does not provide the required accuracy and integrity [9]. Other techniques like Kriging are also proposed for the next generation of WAAS [10][11][12].…”