Determination of the Parameters of a Japanese-Regional Klobuchar Ionospheric Model Based on GR Models and SCH Analysis by GEONET Data

K. Nishimoto, M. Ohashi, Y. Kubo, S. Sugimoto

Abstract:	Ionosheric delay is one of the major error sources in GNSS (Global Navigation Satellite System) positioning. For single frequency system, it is important to effectively correct the ionospheric delay. Theso-called Klobuchar’s ionospheric model has been widely used due to its simple computation and its generality (globalization). However, it is well known that the model may correct about 50% RMS ionospheric errors. In this paper, therefore, we establish a method of determination of the more accurate parameters of the regional Klobuchar model based on GR (GNSS Regression) models and SCHA (Spherical Cap Harmonics Analysis). By the SCH model, it has been reported that the ionospheric delays can be well modeled in the regional area such as the sky over Japan. However, comparing with the Klobuchar model, the SCH model needs more number of parameters and computational burden. We present the method to derive Japanese-regional Klobuchar model based on minimizing mean square errors of Ionosheric delays between SCH models and the regional Klobuchar model. Finally, we examine the accuracy of VTECs estimation and positioning results using our Japanese-regional Klobuchar model, in comparison with using the original global Klobuchar model broadcasted by GPS. Our experimental results show that our regional Klobuchar model works well. In the single frequency usage, we show that our model can improve more than 50% for using the original Klobuchar model in the positioning accuracy.
Published in:	Proceedings of the ION 2013 Pacific PNT Meeting April 23 - 25, 2013 Marriott Waikiki Beach Resort & Spa Honolulu, Hawaii
Pages:	723 - 734
Cite this article:	Nishimoto, K., Ohashi, M., Kubo, Y., Sugimoto, S., "Determination of the Parameters of a Japanese-Regional Klobuchar Ionospheric Model Based on GR Models and SCH Analysis by GEONET Data," Proceedings of the ION 2013 Pacific PNT Meeting, Honolulu, Hawaii, April 2013, pp. 723-734.
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