Ionospheric effects on GPS range finding using 3D ray-tracing and Nelder-Mead optimisation algorithm

Siti Sarah Zulkifli, Mardina Abdullah, Azami Zaharim, Mahamod Ismail

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The Earth's ionosphere plays a crucial role in Global Positioning System (GPS) accuracy because this layer represents the largest source of positioning error for the users of the GPS after the turn-off of Selective Availability (SA). This paper studies the ionospheric effect on transionospheric signal propagation for the Earth-satellite path using 3D Jones Ray-Tracing utilizing Nelder-Mead optimisation algorithm. The ionospheric delay or advance is obtained from the difference between the distance of the ray path from the satellite to the receiver determined from the ray-tracing and the distance for propagation over the line of sight (LOS) at the velocity of light in vacuum. The difference between the standard dual-frequency models corrected range and LOS, known as Residual Range Error (RRE) is calculated. Results show that the RRE of group delay value is different from RRE of phase advance. On the other hand, the group and phase path is longer when considering the geomagnetic field effect on both GPS frequencies L1 and L2. The higher order term in total electron content (TEC) calculation that relates to the refractive index is normally neglected due to its small value, but it is clearly shown that it does have some effects in ray-tracing. This analysis needs to be considered for more accurate GPS range finding.

Original languageEnglish
Pages (from-to)1-10
Number of pages10
JournalWSEAS Transactions on Mathematics
Volume8
Issue number1
Publication statusPublished - 2009

Fingerprint

Geographic Information Systems
Global Positioning System
Ray Tracing
Ray tracing
Global positioning system
Optimization Algorithm
Range of data
Earth (planet)
Path
Satellites
Light velocity
Refractometry
Group delay
Ionosphere
Propagation
Group Delay
Vacuum
Line
Refractive index
Research Design

Keywords

  • GPS
  • Ionosphere
  • Nelder-Mead optimization
  • Ray-tracing
  • RRE

ASJC Scopus subject areas

  • Mathematics(all)

Cite this

Ionospheric effects on GPS range finding using 3D ray-tracing and Nelder-Mead optimisation algorithm. / Zulkifli, Siti Sarah; Abdullah, Mardina; Zaharim, Azami; Ismail, Mahamod.

In: WSEAS Transactions on Mathematics, Vol. 8, No. 1, 2009, p. 1-10.

Research output: Contribution to journalArticle

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