GPS Solutions

, Volume 9, Issue 1, pp 41–50 | Cite as

The ionospheric impact of the October 2003 storm event on Wide Area Augmentation System

  • Attila Komjathy
  • Lawrence Sparks
  • Anthony J. Mannucci
  • Anthea Coster
Original Article

Abstract

The United States Federal Aviation Administration’s (FAA) Wide-Area Augmentation System (WAAS) for civil aircraft navigation is focused primarily on the Conterminous United States (CONUS). Other Satellite-Based Augmentation Systems (SBAS) include the European Geostationary Navigation Overlay Service (EGNOS) and the Japanese Multi-transport Satellite-based Augmentation System (MSAS). Navigation using WAAS requires accurate calibration of ionospheric delays. To provide delay corrections for single frequency global positioning system (GPS) users, the wide-area differential GPS systems depend upon accurate determination of ionospheric total electron content (TEC) along radio links. Dual-frequency transmissions from GPS satellites have been used for many years to measure and map ionospheric TEC on regional and global scales. The October 2003 solar-terrestrial events are significant not only for their dramatic scale, but also for their unique phasing of solar irradiance and geomagnetic events. During 28 October, the solar X-ray and EUV irradiances were exceptionally high while the geomagnetic activity was relatively normal. Conversely, 29–31 October was geomagnetically active while solar irradiances were relatively low. These events had the most severe impact in recent history on the CONUS region and therefore had a significant effect on the WAAS performance. To help better understand the event and its impact on WAAS, we examine in detail the WAAS reference site (WRS) data consisting of triple redundant dual-frequency GPS receivers at 25 different locations within the US. To provide ground-truth, we take advantage of the three co-located GPS receivers at each WAAS reference site. To generate ground-truth and calibrate GPS receiver and transmitter inter-frequency biases, we process the GPS data using the Global Ionospheric Mapping (GIM) software developed at the Jet Propulsion Laboratory. This software allows us to compute calibrated high resolution observations of TEC. We found ionospheric range delays up to 35 m for the day-time CONUS during quiet conditions and up to 100 m during storm time conditions. For a quiet day, we obtained WAAS planar fit slant residuals less than 2 m (0.4 m root mean square (RMS)) and less than 25 m (3.4 m RMS) for the storm day. We also investigated ionospheric gradients, averaged over distances of a few hundred kilometers. The gradients were no larger than 0.5 m over 100 km for a quiet day. For the storm day, we found gradients at the 4 m level over 100 km. Similar level gradients are typically observed in the low-latitude region for quiet or storm conditions.

References

  1. Blanch J, Walter T, Enge P (2002) Application of spatial statistics to ionosphere estimation for WAAS. In: On the CD-ROM of the proceedings of the National Technical Meeting of the Institute of Navigation. San DiegoGoogle Scholar
  2. Enge P, Walter T, Pullen S, Kee C, Chao YC, Tsai Y-J (1996) Wide area augmentation of the global positioning system. Proc IEEE 84:1063–1088CrossRefGoogle Scholar
  3. GIPSY, GPS-Inferred Positioning System (2004). http://gipsy.jpl.nasa.gov/orms/goa/
  4. Iijima BA, Harris IL, Ho CM, Lindqwister UJ, Mannucci AJ, Pi X, Reyes MJ, Sparks LC, Wilson BD (1999) Automated daily process for global ionospheric total electron content maps and satellite ocean altimeter ionospheric calibration based on global positioning system. J Atmos Solar Terrestrial Phys 61:1205–1218CrossRefGoogle Scholar
  5. Komjathy A, Wilson BD, Runge TF, Boulat BM, Mannucci AJ, Sparks L, Reyes MJ (2002) A new ionospheric model for wide area differential GPS: the multiple shell approach. In: On the CD-ROM of the proceedings of the National Technical Meeting of the Institute of Navigation. San DiegoGoogle Scholar
  6. Komjathy A, Sparks L, Mannucci AJ, Pi X (2003a) An alternative ionospheric correction algorithm for Satellite-Based Augmentation Systems in low-latitude region. In: On the CD-ROM of the proceedings of GNSS 2003 The European Navigation Conference. GrazGoogle Scholar
  7. Komjathy A, Sparks L, Mannucci AJ, Pi X (2003b) An assessment of the current WAAS ionospheric correction algorithm in the south American region navigation. NAVIGATION: J Inst Navigation 50(3):193–204Google Scholar
  8. Komjathy A, Sparks L, Mannucci T (2003c) On the ionospheric impact of recent storm events on Satellite-Based Augmentation Systems in the middle and low-latitude regions. In: On the CD-ROM of the 2003 international technical meeting of the Institute of Navigation. PortlandGoogle Scholar
  9. Lawson C (1984) A piecewise C2 basis for function representation over a surface of a sphere. JPL internal documentGoogle Scholar
  10. Mannucci AJ, Wilson BD, Yuan DN, Ho CH, Lindqwister UJ, Runge TF (1998) A global mapping technique for GPS-derived ionospheric total electron content measurements. Radio Sci 33:565–582CrossRefGoogle Scholar
  11. Mannucci AJ, Iijima BA, Sparks L, Pi X, Wilson BD, Lindqwister UJ (1999) Assessment of global TEC mapping using a three-dimensional electron density model. J Atmos Solar Terrestrial Phys 61:1227–1236CrossRefGoogle Scholar
  12. Sparks L, Iijima BA, Mannucci AJ, Pi X, Wilson BD (2000) A new model for retrieving slant TEC corrections for wide area differential GPS. In: Proceedings of the ION National Technical Meeting 2000 of the Institute of Navigation. Anaheim, pp 464–474Google Scholar
  13. Sparks L, Komjathy A, Mannucci AJ (2004a) Sudden ionospheric delay decorrelation and its impact on the Wide Area Augmentation System (WAAS). Radio Sci 39:RS1–S13CrossRefGoogle Scholar
  14. Sparks L, Komjathy A, Mannucci AJ (2004b) Estimating SBAS ionospheric delays without grids: the conical domain approach. In: On the CD-ROM of the ION 2004 National Technical Meeting. San DiegoGoogle Scholar
  15. WAAS MOPS (1999) Minimum operational performance standards for global positioning system/wide area augmentation system airborne equipment. RTCA Inc., Document No. RTCA/DO-229B, p 225Google Scholar
  16. Walter T, Hansen A, Blanch J, Enge P, Mannucci TJ, Pi X, Sparks L, Iijima B, El-Arini B, Lejeune R, Hagen M, Altschuler E, Fries R, Chu A (2000) Robust detection of ionospheric irregularities. In: On the CD-ROM of the proceedings of ION GPS 2000, 13th international technical meeting of the Institute of Navigation. Salt Lake CityGoogle Scholar

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Attila Komjathy
    • 1
  • Lawrence Sparks
    • 1
  • Anthony J. Mannucci
    • 1
  • Anthea Coster
    • 2
  1. 1.Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaUSA
  2. 2.MIT Haystack ObservatoryAtmospheric SciencesWestfordUSA

Personalised recommendations