Details
| Original language | English |
|---|---|
| Article number | 66 |
| Journal | GPS solutions |
| Volume | 22 |
| Issue number | 3 |
| Publication status | Published - 25 Apr 2018 |
Abstract
With three near-polar low earth orbiter satellites, the Swarm mission contributes to bridging the gap between Earth gravity field missions. However, observations from on-board GPS receivers are strongly impacted by ionospheric scintillations, degrading the kinematic orbit solutions of the satellites and thus the gravity field, which is derived from them. Besides the elimination of parts of the GPS observations strongly impacted by scintillations, an alternative is a physically based filtering of these measurements. Based on the previous empirical and theoretical works, a Matérn covariance function, whose parameters are to be chosen adequately, is an answer to mitigate ionospheric effects from the GPS time series. An optimal parameter set corresponding to a smoothness of 1 and a correlation factor of 1.5 is physically plausible and provides an adequate filtering of the ionospheric scintillations. The detection of noisy parts is carried out with an easy to use algorithm to obtain filtered time series with a homogeneous standard deviation. The orbit solution computed with filtered observations does not exhibit ionospheric artifacts compared with the non-filtered solution. At the same time, the high-frequency slope of the orbit power spectral density is similar to the one obtained for GPS carrier phase observations with low ionospheric scintillation errors. The proposed methodology is independent of the processing used, whether double differences, Observed Minus Computed or raw carrier phase observations.
Keywords
- GPS, Ionospheric scintillations, Kinematic orbit, Matérn family, SWARM
ASJC Scopus subject areas
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In: GPS solutions, Vol. 22, No. 3, 66, 25.04.2018.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - On filtering ionospheric effects in GPS observations using the Matérn covariance family and its impact on orbit determination of Swarm satellites
AU - Kermarrec, Gaël
AU - Ren, Le
AU - Schön, Steffen
N1 - Funding information: The results are obtained within the project CON-TIM and funded by the Deutsche Forschungsgemeinschaft (DFG) under the SPP1788 Dynamic Earth. The Swarm reduced-dynamic orbits have been made available by European Space Agency (ESA). GPS orbits and clock have been obtained from the Center for Orbit Determination in Europe (CODE). The support of these institutions is gratefully acknowledged. The reviewers are warmly acknowledged for their constructive comments.
PY - 2018/4/25
Y1 - 2018/4/25
N2 - With three near-polar low earth orbiter satellites, the Swarm mission contributes to bridging the gap between Earth gravity field missions. However, observations from on-board GPS receivers are strongly impacted by ionospheric scintillations, degrading the kinematic orbit solutions of the satellites and thus the gravity field, which is derived from them. Besides the elimination of parts of the GPS observations strongly impacted by scintillations, an alternative is a physically based filtering of these measurements. Based on the previous empirical and theoretical works, a Matérn covariance function, whose parameters are to be chosen adequately, is an answer to mitigate ionospheric effects from the GPS time series. An optimal parameter set corresponding to a smoothness of 1 and a correlation factor of 1.5 is physically plausible and provides an adequate filtering of the ionospheric scintillations. The detection of noisy parts is carried out with an easy to use algorithm to obtain filtered time series with a homogeneous standard deviation. The orbit solution computed with filtered observations does not exhibit ionospheric artifacts compared with the non-filtered solution. At the same time, the high-frequency slope of the orbit power spectral density is similar to the one obtained for GPS carrier phase observations with low ionospheric scintillation errors. The proposed methodology is independent of the processing used, whether double differences, Observed Minus Computed or raw carrier phase observations.
AB - With three near-polar low earth orbiter satellites, the Swarm mission contributes to bridging the gap between Earth gravity field missions. However, observations from on-board GPS receivers are strongly impacted by ionospheric scintillations, degrading the kinematic orbit solutions of the satellites and thus the gravity field, which is derived from them. Besides the elimination of parts of the GPS observations strongly impacted by scintillations, an alternative is a physically based filtering of these measurements. Based on the previous empirical and theoretical works, a Matérn covariance function, whose parameters are to be chosen adequately, is an answer to mitigate ionospheric effects from the GPS time series. An optimal parameter set corresponding to a smoothness of 1 and a correlation factor of 1.5 is physically plausible and provides an adequate filtering of the ionospheric scintillations. The detection of noisy parts is carried out with an easy to use algorithm to obtain filtered time series with a homogeneous standard deviation. The orbit solution computed with filtered observations does not exhibit ionospheric artifacts compared with the non-filtered solution. At the same time, the high-frequency slope of the orbit power spectral density is similar to the one obtained for GPS carrier phase observations with low ionospheric scintillation errors. The proposed methodology is independent of the processing used, whether double differences, Observed Minus Computed or raw carrier phase observations.
KW - GPS
KW - Ionospheric scintillations
KW - Kinematic orbit
KW - Matérn family
KW - SWARM
UR - http://www.scopus.com/inward/record.url?scp=85046265965&partnerID=8YFLogxK
U2 - 10.1007/s10291-018-0733-y
DO - 10.1007/s10291-018-0733-y
M3 - Article
AN - SCOPUS:85046265965
VL - 22
JO - GPS solutions
JF - GPS solutions
SN - 1080-5370
IS - 3
M1 - 66
ER -