TY - GEN
T1 - The improved TaiWan Ionospheric Model (TWIM) and ITS applications on GPS positioning
AU - Tsai, L. C.
AU - Zheng, C. W.
AU - Macalalad, Ernest P.
AU - Chen, G. H.
AU - Tien, M. H.
PY - 2012
Y1 - 2012
N2 - A three-dimensional ionospheric electron density (Ne) model (L.-C. Tsai, C. H. Liu, T. Y. Hsiao, and J. Y. Huang, Radio Sci., 44, doi:10.1029/2009RS004154, 2009) has been named the TaiWan Ionospheric Model (TWIM) and constructed from vertical Ne profiles retrieved from FormoSat3/COSMIC GPS radio occultation measurements. We further improved the TWIM by including global distributed ionosonde foF2 and foE data and qualifying COSMIC Ne profiles based on the empirical orthogonal function (EOF) classification. The improved TWIM also exhibits vertically-fitted α-Chapman-type layers, with distinct F2, F1, E, and D layers, and surface spherical harmonics approaches for the fitted layer parameters including peak density, peak density height, and scale height. These results are useful in investigation of near-Earth space and large-scale Ne distribution. This way the continuity of Ne and its derivatives is also maintained for practical schemes for providing reliable radio propagation predictions. We have presented a numerical and step by step ray-tracing method (L.-C. Tsai, C. H. Liu, and J. Y. Huang, Radio Sci., 45, doi:10.1029/ 2010RS004359, 2010) on the TWIM and including an Earth-centered magnetic dipole and horizontal Ne gradient effects. The ray-tracing methodology has potential applicability to ionospheric correction as applied to GPS positioning. In this paper, ionospheric corrections on both single-receiver and double-receiver L1 GPS code measurements using the TWIM have been presented and evaluated. Its performances with respect with the ionospheric corrections using other ionospheric models are also presented and compared.
AB - A three-dimensional ionospheric electron density (Ne) model (L.-C. Tsai, C. H. Liu, T. Y. Hsiao, and J. Y. Huang, Radio Sci., 44, doi:10.1029/2009RS004154, 2009) has been named the TaiWan Ionospheric Model (TWIM) and constructed from vertical Ne profiles retrieved from FormoSat3/COSMIC GPS radio occultation measurements. We further improved the TWIM by including global distributed ionosonde foF2 and foE data and qualifying COSMIC Ne profiles based on the empirical orthogonal function (EOF) classification. The improved TWIM also exhibits vertically-fitted α-Chapman-type layers, with distinct F2, F1, E, and D layers, and surface spherical harmonics approaches for the fitted layer parameters including peak density, peak density height, and scale height. These results are useful in investigation of near-Earth space and large-scale Ne distribution. This way the continuity of Ne and its derivatives is also maintained for practical schemes for providing reliable radio propagation predictions. We have presented a numerical and step by step ray-tracing method (L.-C. Tsai, C. H. Liu, and J. Y. Huang, Radio Sci., 45, doi:10.1029/ 2010RS004359, 2010) on the TWIM and including an Earth-centered magnetic dipole and horizontal Ne gradient effects. The ray-tracing methodology has potential applicability to ionospheric correction as applied to GPS positioning. In this paper, ionospheric corrections on both single-receiver and double-receiver L1 GPS code measurements using the TWIM have been presented and evaluated. Its performances with respect with the ionospheric corrections using other ionospheric models are also presented and compared.
KW - GPS positioning
KW - GPS radio occultation
KW - Ionospheric electron density model
UR - http://www.scopus.com/inward/record.url?scp=84879998838&partnerID=8YFLogxK
M3 - 會議論文篇章
AN - SCOPUS:84879998838
SN - 9781622769742
T3 - 33rd Asian Conference on Remote Sensing 2012, ACRS 2012
SP - 1541
EP - 1546
BT - 33rd Asian Conference on Remote Sensing 2012, ACRS 2012
T2 - 33rd Asian Conference on Remote Sensing 2012, ACRS 2012
Y2 - 26 November 2012 through 30 November 2012
ER -