TY - GEN
T1 - The TaiWan Ionospheric Model (TWIM) and its applications on radio wave propagation and ionospheric GPS L1 pseudorange correction
AU - Tsai, L. C.
AU - Chen, G. H.
AU - Tian, M. H.
AU - MacAlalad, Ernest P.
PY - 2011
Y1 - 2011
N2 - A three-dimensional ionospheric electron density (N e) model has been named the TaiWan Ionospheric Model (TWIM) and constructed from monthly-weighted and hourly vertical Ne profiles retrieved from FormoSat3/COSMIC GPS radio occultation (RO) measurements. The TWIM 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 N e distribution. This way the continuity of N e and its derivatives is also maintained for practical schemes for providing reliable radio propagation predictions. We also present a numerical and step by step ray-tracing method on the TWIM. With the Earth's magnetic field and horizontal N e gradient effects included, efficient methods for calculating ray parameters such as phase path and group path are presented. The methodology has been successfully applied to a practical high-frequency transmitter for oblique incidence ray tracing and further evaluated by comparing synthetic vertical ionograms generated by the method with experimental ionosonde observations. Furthermore, the ray-tracing methodology also has potential applicability to ionospheric correction as applied to single frequency GPS receivers. In this paper, ionospheric delay correction for single-frequency GPS pseudoranges using the TWIM is presented. Its performance with respect with the ionospheric correction using other ionospheric model and the dual-frequency GPS receiver will also be presented.
AB - A three-dimensional ionospheric electron density (N e) model has been named the TaiWan Ionospheric Model (TWIM) and constructed from monthly-weighted and hourly vertical Ne profiles retrieved from FormoSat3/COSMIC GPS radio occultation (RO) measurements. The TWIM 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 N e distribution. This way the continuity of N e and its derivatives is also maintained for practical schemes for providing reliable radio propagation predictions. We also present a numerical and step by step ray-tracing method on the TWIM. With the Earth's magnetic field and horizontal N e gradient effects included, efficient methods for calculating ray parameters such as phase path and group path are presented. The methodology has been successfully applied to a practical high-frequency transmitter for oblique incidence ray tracing and further evaluated by comparing synthetic vertical ionograms generated by the method with experimental ionosonde observations. Furthermore, the ray-tracing methodology also has potential applicability to ionospheric correction as applied to single frequency GPS receivers. In this paper, ionospheric delay correction for single-frequency GPS pseudoranges using the TWIM is presented. Its performance with respect with the ionospheric correction using other ionospheric model and the dual-frequency GPS receiver will also be presented.
KW - GPS positioning
KW - GPS radio occultation
KW - Ionospheric electron density model
UR - https://www.scopus.com/pages/publications/84865700979
M3 - 會議論文篇章
AN - SCOPUS:84865700979
SN - 9781618394972
T3 - 32nd Asian Conference on Remote Sensing 2011, ACRS 2011
SP - 27
EP - 34
BT - 32nd Asian Conference on Remote Sensing 2011, ACRS 2011
T2 - 32nd Asian Conference on Remote Sensing 2011, ACRS 2011
Y2 - 3 October 2011 through 7 October 2011
ER -