Hoque, Mohammed Mainul and Jakowski, Norbert (2007) Ionospheric Refraction on GPS Signals Received Onboard LEO Satellites. In: European Geosciences Union General Assembly 2007. European Geosciences Union General Assembly 2007, 2007-04-15 - 2007-04-20, Vienna, Austria.
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The bending of the ray-path of GNSS signals is caused by the ionospheric refractivity which mainly depends on the electron density distribution along the ray path. Bending effects lead to a deviation of the curved optical path from the straight line of sight (LoS). Due to the dispersive nature of the ionosphere GNSS signals at L1 and L2 frequencies travel along different ray paths through the ionosphere. In both cases the ray path is longer than the length of the LoS, in particular at low elevation angles at ground based receivers. The corresponding excess path in addition to the LoS or true range may achieve several centimeters at low elevations under high solar activity conditions. Radio occultation measurements onboard Low Earth Orbiting (LEO) satellites indicate ionospheric bending effects of the excess path up to the meter level. The corresponding errors in TEC estimates used for retrieving vertical electron density profiles from GPS radio occultation measurements are discussed. The computed deviations of the curved optical path from the straight LoS may reach the kilometer level. Consequently, the tangential heights of the signal paths at the closest point of approach to the Earth surface deviate from that defined by the straight LoS propagation. This may cause an error in determining the reference height in the retrieved vertical refractivity profiles.
|Document Type:||Conference or Workshop Item (Speech)|
|Title:||Ionospheric Refraction on GPS Signals Received Onboard LEO Satellites|
|Journal or Publication Title:||European Geosciences Union General Assembly 2007|
|In ISI Web of Science:||No|
|Keywords:||Ionosphreic refraction, Ray-path deviation, Ray-path bending error|
|Event Title:||European Geosciences Union General Assembly 2007|
|Event Location:||Vienna, Austria|
|Event Type:||international Conference|
|Event Dates:||2007-04-15 - 2007-04-20|
|HGF - Research field:||Aeronautics, Space and Transport (old)|
|HGF - Program:||Space (old)|
|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|
|Deposited By:||Mohammed Mainul Hoque|
|Deposited On:||06 Aug 2007|
|Last Modified:||15 Jan 2010 00:25|
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