HIGHER ORDER IONOSPHERIC ERRORS IN MODERNIZED GPS AND FUTURE GALILEO SYSTEMS
Hoque, Mohammed Mainul and Jakowski, Norbert (2010) HIGHER ORDER IONOSPHERIC ERRORS IN MODERNIZED GPS AND FUTURE GALILEO SYSTEMS. Space Science, Exploration and Policies, Global Positioning Systems. Nova Science Publishers. ISBN 978-1-60741-012-6.
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Modernized GPS and future Galileo systems will transmit a third frequency allowing to cancel out the first and second order ionospheric terms in the refractive index by double differencing carrier phases or code pseudoranges. However, differential bending of the signal and third order ionospheric term are not fully removed in this approach. This work estimates the magnitude of various higher order ionospheric errors using a large number of ionospheric vertical profiles reconstructed from CHAMP-GPS radio occultation measurements. Our investigation shows that triple-frequency residual range errors become significant at low elevation angles (< 15°) and at high level of total electron content. The triple-frequency residual range error reaches up to 1 and 4 cm at 5° elevation angle in carrier-phase and pseudo-range measurements, respectively. Different approximation formulas have been discussed to mitigate higher order ionospheric errors in operating satellite positioning systems. The Galileo system will allow four frequencies to be used for higher order ionospheric corrections. It has been found that ionospheric effects are successfully removed in quadruple-frequency measurements, i.e., no ionospheric correction is required in the range estimation. However, quadruple-frequency measurements for the ionospheric correction are not practically useful since the measurement noise exceeds the ionospheric correction.
|Title:||HIGHER ORDER IONOSPHERIC ERRORS IN MODERNIZED GPS AND FUTURE GALILEO SYSTEMS|
|Volume:||Global Positioning Systems|
|Page Range:||pp. 1-28|
|Publisher:||Nova Science Publishers|
|Series Name:||Space Science, Exploration and Policies|
|Keywords:||Higher order ionospheric errors, GNSS positioning, correction formulas|
|HGF - Research field:||Aeronautics, Space and Transport|
|HGF - Program:||Space|
|HGF - Program Themes:||W EW - Erforschung des Weltraums|
|DLR - Research area:||Space|
|DLR - Program:||W EW - Erforschung des Weltraums|
|DLR - Research theme (Project):||W - Vorhaben Weltraumwetter (old)|
|Institutes and Institutions:||Institute of Communication and Navigation > Navigation|
|Deposited By:||Mohammed Mainul Hoque|
|Deposited On:||29 Jun 2011 09:00|
|Last Modified:||29 Jun 2011 09:00|
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