caa a22 4500 445814357 CHVBK 20180317145221.0 cr unu---uuuuu 170323e20110501xx s 000 0 eng 10.1007/s10712-010-9105-z doi (NATIONALLICENCE)springer-10.1007/s10712-010-9105-z A Review of Higher Order Ionospheric Refraction Effects on Dual Frequency GPS [Elektronische Daten] [Elizabeth Petrie, Manuel Hernández-Pajares, Paolo Spalla, Philip Moore, Matt King] Higher order ionospheric effects are increasingly relevant as precision requirements on GPS data and products increase. The refractive index of the ionosphere is affected by its electron content and the magnetic field of the Earth, so the carrier phase of the GPS L1 and L2 signals is advanced and the modulated code delayed. Due to system design the polarisation is unaffected. Most of the effect is removed by expanding the refractive index as a series and eliminating the first term with a linear combination of the two signals. However, the higher order terms remain. Furthermore, transiting gradients in refractive index at a non-perpendicular angle causes signal bending. In addition to the initial geometric bending term, another term allows for the difference that the curvature makes in electron content along each signal. Varying approximations have been made for practical implementation, mainly to avoid the need for a vertical profile of electron density. The magnetic field may be modelled as a tilted co-centric dipole, or using more realistic models such as the International Geomagnetic Reference Field. The largest effect is from the second term in the expansion of the refractive index. Up to several cm on L2, it particularly affects z-translation, and satellite orbits and clocks in a global network of GPS stations. The third term is at the level of the errors in modelling the second order term, while the bending terms appear to be absorbed by tropospheric parameters. Modelling improvements are possible, and three frequency transmissions will allow new possibilities. Springer Science+Business Media B.V., 2010 Higher-order effects nationallicence Ionosphere nationallicence GPS nationallicence Refractive index nationallicence Signal bending nationallicence Petrie Elizabeth School of Civil Engineering and Geosciences, Newcastle University, NE1 7RU, Newcastle upon Tyne, UK aut Hernández-Pajares Manuel Research Group of Astronomy and Geomatics, Technical University of Catalonia (gAGE/UPC), Mod. C3, Campus Nord UPC, Jordi Girona 1, 08034, Barcelona, Spain aut Spalla Paolo IFAC-CNR, Via Madonna del Piano 10, 50019, Sesto Fiorentino, Italy aut Moore Philip School of Civil Engineering and Geosciences, Newcastle University, NE1 7RU, Newcastle upon Tyne, UK aut King Matt School of Civil Engineering and Geosciences, Newcastle University, NE1 7RU, Newcastle upon Tyne, UK aut Surveys in Geophysics Springer Netherlands 32/3(2011-05-01), 197-253 0169-3298 32:3<197 2011 32 10712 https://doi.org/10.1007/s10712-010-9105-z text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10712-010-9105-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Petrie Elizabeth School of Civil Engineering and Geosciences, Newcastle University, NE1 7RU, Newcastle upon Tyne, UK aut NATIONALLICENCE 700 1- Hernández-Pajares Manuel Research Group of Astronomy and Geomatics, Technical University of Catalonia (gAGE/UPC), Mod. C3, Campus Nord UPC, Jordi Girona 1, 08034, Barcelona, Spain aut NATIONALLICENCE 700 1- Spalla Paolo IFAC-CNR, Via Madonna del Piano 10, 50019, Sesto Fiorentino, Italy aut NATIONALLICENCE 700 1- Moore Philip School of Civil Engineering and Geosciences, Newcastle University, NE1 7RU, Newcastle upon Tyne, UK aut NATIONALLICENCE 700 1- King Matt School of Civil Engineering and Geosciences, Newcastle University, NE1 7RU, Newcastle upon Tyne, UK aut NATIONALLICENCE 773 0- Surveys in Geophysics Springer Netherlands 32/3(2011-05-01), 197-253 0169-3298 32:3<197 2011 32 10712 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer