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Satellite CPF Predictions

The ILRS network uses CPF orbit predictions provided by mission operators and analysis centres.


The SGF calculates precise satellite orbit predictions daily for most of the ILRS targets and makes these orbits available to other SLR stations internationally. These predictions can be compared in advance to those from other CPF providers so that stations and providers can be confident in their accuracy.

The Consolidated Prediction Format (CPF) is the official format used by the ILRS. It consists of geocentric X, Y, and Z positions at different epochs that can be interpolated for very accurate predictions. Accurate prediction of the positions of the full range of laser-tracked satellites is possible in a single, simple format.

The plots below compare the CPFs when there is more than one provider by taking the differences in metres between the orbital X, Y and Z values at zero hours for today and for the next three or four days.

Full residual plot comparisons are plotted here.
           Difference between CPF Providers
        JD            X             Y             Z
Ajisai SGF - ITT    
 aji   58465.         3.764        -2.085        -4.368
 aji   58466.         3.034        -5.249        -4.039
 aji   58467.         3.800        -8.816        -4.114
 aji   58468.         4.222       -13.099        -4.873
Ajisai ITT - JAX    
 aji   58465.        -3.711         1.371         4.315
 aji   58466.        -3.016         4.186         3.939
 aji   58467.        -3.702         7.373         3.988
Ajisai JAX - SGF    
 aji   58465.        -0.053         0.714         0.054
 aji   58466.        -0.018         1.062         0.100
 aji   58467.        -0.097         1.443         0.126
Beacon-C SGF - ITT  
 bec   58465.         0.435       -25.709        -7.797
 bec   58466.         1.005       -44.977       -13.662
 bec   58467.        -0.909       -60.227       -20.616
 bec   58468.        -4.819       -65.053       -26.522
Cyrosat-2 ESA - ITT 
 cyb   58465.       251.847       -15.723      -193.461
 cyb   58466.       315.262       216.717      -256.147
 cyb   58467.       338.994       518.779      -276.124
Etalon-1 SGF - ITT  
 eta   58465.         9.977         8.523        -6.941
 eta   58466.         9.732        10.617        -9.213
 eta   58467.         8.674        12.700       -10.908
 eta   58468.         8.971        15.925       -12.673
Etalon-2 SGF - ITT  
 etb   58465.         8.058         7.793       -10.964
 etb   58466.         8.390         6.341        -9.947
 etb   58467.         9.215         8.977       -13.483
 etb   58468.        11.521        10.273       -17.083
Jason-2 SGF - ITT   
 jsb   58465.         4.302        -5.971        -4.098
 jsb   58466.         3.941        -9.830        -5.630
 jsb   58467.         4.244       -13.146        -7.779
Jason-2 ITT - CNES  
 jsb   58465.        -3.143         6.281         1.221
 jsb   58466.        -2.651        11.801         1.769
 jsb   58467.        -3.050        17.749         2.896
Jason-2 CNES - SGF  
 jsb   58465.        -1.159        -0.310         2.877
 jsb   58466.        -1.291        -1.971         3.860
 jsb   58467.        -1.193        -4.603         4.884
 jsb   58468.        -1.069        -7.931         6.086
Larets SGF - ITT    
 lar   58465.         2.874         1.143         0.468
 lar   58466.         2.770         1.245         0.908
 lar   58467.         2.881         0.785         1.142
 lar   58468.         2.849         0.036         1.136
LARES SGF - ITT     
 las   58465.         4.898         3.113        -4.055
 las   58466.         5.021         3.712        -5.523
 las   58467.         5.313         4.249        -6.232
LAGEOS-1 SGF - ITT  
 lga   58465.         5.830         4.340        -2.450
 lga   58466.         5.812         5.094        -3.260
 lga   58467.         5.334         6.256        -3.864
 lga   58468.         6.853         8.546        -5.268
LAGEOS-1 ITT - JAX  
 lga   58465.        -5.919        -4.496         2.560
 lga   58466.        -5.840        -5.269         3.372
 lga   58467.        -5.366        -6.523         3.872
LAGEOS-1 JAX - SGF  
 lga   58465.         0.090         0.156        -0.111
 lga   58466.         0.028         0.175        -0.112
 lga   58467.         0.031         0.266        -0.008
LAGEOS-2 SGF - ITT  
 lgb   58465.         5.821        19.619        -0.431
 lgb   58466.         4.036        24.955         1.204
 lgb   58467.         8.779        36.091        -0.999
LAGEOS-2 ITT - JAX  
 lgb   58465.        -5.893       -20.989         0.661
 lgb   58466.        -3.951       -26.611        -1.042
 lgb   58467.        -9.027       -38.429         1.411
LAGEOS-2 JAX - SGF  
 lgb   58465.         0.072         1.370        -0.230
 lgb   58466.        -0.084         1.656        -0.162
 lgb   58467.         0.248         2.338        -0.411
Stella SGF - ITT    
 ste   58465.         2.215        -3.405        -0.095
 ste   58466.         2.000        -5.856         0.706
 ste   58467.         1.037        -9.888         1.539
Starlette SGF - ITT 
 str   58465.         3.304         0.907        -2.095
 str   58466.         3.513         3.367        -1.783
 str   58467.         3.806         7.986        -1.830