Ionospheric differential error determination using ray tracing for a short baseline

Mardina Abdullah, H. J. Strangeways, S. S N Zulkifli

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Since the United States government discontinued Selective Availability (SA) on 1 May 2000, ionospheric effects have been responsible for the largest errors in GPS systems. The standard Differential GPS (DGPS) method is incapable of completely eliminating the ionospheric error. This paper describes a new approach to determine the differential ionospheric error between geographically distributed receiver stations. The ray paths of GPS signals were simulated using a modified Jones 3D ray tracing programme that includes the effect of the geomagnetic field. A Nelder-Mead optimisation algorithm was embedded in the program to precisely determine the satellite-to-station path. A realistic ionospheric model is essential for accurate ray tracing results and for estimates of differential error that are accurate on sub-centimetre scales. Here, the ionospheric model used in the ray tracing programme was developed by fitting realistic ionosphere profiles with a number of exponential functions. Results were compared to the theoretical approach. Results show that the differential delay is about 1-5 cm at low elevation angles for a short baseline of 10 km, as reported in other literature. This delay is often neglected in DGPS application. The differential delay also shows a pattern similar to that predicted by the Klobuchar model. The method proposed here can be used to improve future GPS applications.

Original languageEnglish
Pages (from-to)1326-1333
Number of pages8
JournalAdvances in Space Research
Volume46
Issue number10
DOIs
Publication statusPublished - 15 Nov 2010

Fingerprint

ray tracing
Ray tracing
ionospherics
Global positioning system
GPS
stations
elevation angle
Ionosphere
Exponential functions
exponential functions
geomagnetism
geomagnetic field
ionospheres
availability
ionosphere
rays
receivers
Availability
Satellites
optimization

Keywords

  • GPS
  • Ionosphere
  • Ray tracing
  • Short baseline
  • TEC

ASJC Scopus subject areas

  • Aerospace Engineering
  • Space and Planetary Science

Cite this

Ionospheric differential error determination using ray tracing for a short baseline. / Abdullah, Mardina; Strangeways, H. J.; Zulkifli, S. S N.

In: Advances in Space Research, Vol. 46, No. 10, 15.11.2010, p. 1326-1333.

Research output: Contribution to journalArticle

Abdullah, Mardina ; Strangeways, H. J. ; Zulkifli, S. S N. / Ionospheric differential error determination using ray tracing for a short baseline. In: Advances in Space Research. 2010 ; Vol. 46, No. 10. pp. 1326-1333.
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