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Ionosphere-free Combination for Dual Frequency Receivers: Difference between revisions
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According to the phase and code [[Ionospheric Delay|ionospheric refraction]], the first order ionospheric effects on code <math>R_{P}</math> and carrier-phase <math>\Phi_L</math> measurements depends (99.9%) on the inverse of squared signal frequency <math>f</math>.Thence, the dual-frequency receivers can eliminate its effect through a linear combination of code or carrier measurements: | According to the phase and code [[Ionospheric Delay|ionospheric refraction]], the first order ionospheric effects on code <math>R_{P}</math> and carrier-phase <math>\Phi_L</math> measurements depends (99.9%) on the inverse of squared signal frequency <math>f</math>.Thence, the dual-frequency receivers can eliminate its effect through a linear combination of code or carrier measurements: | ||
::<math>\Phi_{_{\mbox{iono-free}}}=\frac{f_1^2\;\Phi_{_{L_1}}-f_2^2\;\Phi_{_{L_2}}}{f_1^2-f_2^2} </math> | ::<math>\Phi_{_{\mbox{iono-free}}}=\frac{f_1^2\;\Phi_{_{L_1}}-f_2^2\;\Phi_{_{L_2}}}{f_1^2-f_2^2} </math> | ||
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This combination is named ''Ionosphere-free'' (see [[Combining Pairs of | This combination is named ''Ionosphere-free'' (see [[Combination of GNSS Measurements]] and [[Combining pairs of signals and clock definition|Combining Pairs of Signals]]). | ||
It must be pointed out that the Precise Point Positioning uses code and carrier phase measurements in the ionosphere-free combination to remove the [[Ionospheric Delay|ionospheric refraction]], because it is one of the effects more difficult to model accurately. Moreover the TGDs also cancel in this combination and are not needed (being the satellite clocks referred to the ionospheric free combination of such codes, see | It must be pointed out that the [[Code and Carrier based positioning (PPP)|Precise Point Positioning]] uses code and carrier phase measurements in the ionosphere-free combination to remove the [[Ionospheric Delay|ionospheric refraction]], because it is one of the effects more difficult to model accurately. Moreover the TGDs also cancel in this combination and are not needed (being the satellite clocks referred to the ionospheric free combination of such codes, see [[Combining pairs of signals and clock definition|Combining Pairs of Signals]]). | ||
[[Category:Fundamentals]] | [[Category:Fundamentals]] | ||
Revision as of 10:05, 8 August 2011
| Fundamentals | |
|---|---|
| Title | Ionosphere-free Combination for Dual Frequency Receivers |
| Author(s) | J. Sanz Subirana, JM. Juan Zornoza and M. Hernandez-Pajares, University of Catalunia, Spain. |
| Level | Basic |
| Year of Publication | 2011 |
According to the phase and code ionospheric refraction, the first order ionospheric effects on code [math]\displaystyle{ R_{P} }[/math] and carrier-phase [math]\displaystyle{ \Phi_L }[/math] measurements depends (99.9%) on the inverse of squared signal frequency [math]\displaystyle{ f }[/math].Thence, the dual-frequency receivers can eliminate its effect through a linear combination of code or carrier measurements:
- [math]\displaystyle{ \Phi_{_{\mbox{iono-free}}}=\frac{f_1^2\;\Phi_{_{L_1}}-f_2^2\;\Phi_{_{L_2}}}{f_1^2-f_2^2} }[/math]
- [math]\displaystyle{ R_{_{\mbox{iono-free}}}=\frac{f_1^2\;R_{_{P_1}}-f_2^2\;R_{_{P_2}}}{f_1^2-f_2^2} \qquad\mbox{(1)} }[/math]
This combination is named Ionosphere-free (see Combination of GNSS Measurements and Combining Pairs of Signals).
It must be pointed out that the Precise Point Positioning uses code and carrier phase measurements in the ionosphere-free combination to remove the ionospheric refraction, because it is one of the effects more difficult to model accurately. Moreover the TGDs also cancel in this combination and are not needed (being the satellite clocks referred to the ionospheric free combination of such codes, see Combining Pairs of Signals).