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Coordinates Computation from Almanac Data: Difference between revisions

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(Corrected typo in equation 1: idot is equal to zero and not i.)
 
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{{Article Infobox2
{{Article Infobox2
|Category=Fundamentals
|Category=Fundamentals
|Authors=J. Sanz Subirana, J.M. Juan Zornoza and M. Hernández-Pajares, Technical University of Catalonia, Spain.
|Level=Basic
|YearOfPublication=2011
|Title={{PAGENAME}}
|Title={{PAGENAME}}
|Authors= J. Sanz Subirana, JM. Juan Zornoza and M. Hernandez-Pajares, University of Catalunia, Spain.
|Level=Medium
|YearOfPublication=2011
|Logo=gAGE
}}
}}
The almanac data allow to compute a raw estimation of the satellites coordinates (1-2 km  <math>1- \sigma</math> error), which is needed for signal acquisition by the receiver.


The almanac data allow to compute a raw estimation of the satellites coordinates (1-2 km  1-$\sigma$ error), which is needed for signal acquisition by the receiver.
The almanac data consist of a reduced set of parameters (with respect to broadcast ephemeris), as it is shown in table 1 for GPS satellites. Similar data is broadcast for Galileo.


The almanac data consist of a reduced set of parameters (with respect to broadcast ephemeris), as it is shown in table 1 for GPS satellites. Similar data is broadcast for Galileo.
::[[File: Coord_Comp_Alm.png|none|thumb|640px|'''''Table 1:''''' GPS broadcast almanac parameters.]] 


Thence, the same equations as in article [[GPS and Galileo Satellite Coordinates Computation]] can be used to compute the coordinates from almanac, just taking:
Thence, the same equations as in article [[GPS and Galileo Satellite Coordinates Computation]] can be used to compute the coordinates from almanac, just taking:


::<math> \Delta n =C_{uc}=C_{us}=C_{rc}=C_{rs}=C_{ic}=C_{is}=0</math>
::<math>  
 
\Delta n = \dot{i} = C_{uc}=C_{us}=C_{rc}=C_{rs}=C_{ic}=C_{is}=0
and
\qquad \mbox{(1)}
 
</math>
::<math> i=54^o+\delta i \mbox{\hspace{1cm}(GPS satellites)} </math>


:and


::[[File: Coord_Comp_Alm.png|none|thumb|400px|'''''Table 1:''''' GPS broadcast almanac parameters.]] 
::<math>
i=54^o+\delta i
\qquad \mbox{(GPS satellites).}
\qquad \mbox{(2)}
</math>




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[[Category:Fundamentals]]
[[Category:Fundamentals]]
[[Category:GNSS Time Reference, Coordinate Frames and Orbits]]
[[Category:GPS]]
[[Category:GPS]]

Latest revision as of 06:41, 10 May 2022


FundamentalsFundamentals
Title Coordinates Computation from Almanac Data
Author(s) J. Sanz Subirana, J.M. Juan Zornoza and M. Hernández-Pajares, Technical University of Catalonia, Spain.
Level Basic
Year of Publication 2011

The almanac data allow to compute a raw estimation of the satellites coordinates (1-2 km [math]\displaystyle{ 1- \sigma }[/math] error), which is needed for signal acquisition by the receiver.

The almanac data consist of a reduced set of parameters (with respect to broadcast ephemeris), as it is shown in table 1 for GPS satellites. Similar data is broadcast for Galileo.

Table 1: GPS broadcast almanac parameters.

Thence, the same equations as in article GPS and Galileo Satellite Coordinates Computation can be used to compute the coordinates from almanac, just taking:

[math]\displaystyle{ \Delta n = \dot{i} = C_{uc}=C_{us}=C_{rc}=C_{rs}=C_{ic}=C_{is}=0 \qquad \mbox{(1)} }[/math]
and
[math]\displaystyle{ i=54^o+\delta i \qquad \mbox{(GPS satellites).} \qquad \mbox{(2)} }[/math]


Notes

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