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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   58169.         0.608         1.875        -0.332
 aji   58170.         0.528         2.191        -0.166
 aji   58171.         0.546         2.562         0.023
 aji   58172.         0.590         3.062        -0.204
Ajisai ITT - JAX    
 aji   58169.        -0.634        -1.148         0.118
 aji   58170.        -0.633        -0.847        -0.146
 aji   58171.        -0.444        -0.187        -0.626
Ajisai JAX - SGF    
 aji   58169.         0.026        -0.727         0.214
 aji   58170.         0.105        -1.344         0.312
 aji   58171.        -0.061        -2.317         0.524
Beacon-C SGF - ITT  
 bec   58169.        -2.217        16.382        -1.492
 bec   58170.        -2.763        21.981        -4.510
 bec   58171.        -3.207        22.331        -7.800
 bec   58172.        -4.012        17.069       -15.698
Cyrosat-2 ESA - ITT 
 cyb   58169.        -9.135         3.319        11.698
 cyb   58170.       -16.532         9.676        19.844
 cyb   58171.       -27.723        22.000        30.995
 cyb   58172.       -36.627        33.762        44.243
Etalon-1 SGF - ITT  
 eta   58169.         1.785         5.694         1.331
 eta   58170.         1.624         7.460         1.057
 eta   58171.        -0.054         9.920         0.447
 eta   58172.         3.459         8.246         3.148
Etalon-2 SGF - ITT  
 etb   58169.         0.825         6.871        -0.592
 etb   58170.         0.320         7.303        -0.173
 etb   58171.         2.904         6.491        -1.376
 etb   58172.        -0.656         8.853         1.512
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
 jsb   58169.        -0.018         8.355         0.110
 jsb   58170.         1.478        20.884        -0.446
 jsb   58171.         4.310        39.449        -2.699
 jsb   58172.        -6.830        66.311         6.654
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   58169.        -1.505         4.961         2.290
 lar   58170.        -0.995        13.036         1.956
 lar   58171.        -8.247        22.787         7.511
 lar   58172.        -2.940        42.738         4.567
LARES SGF - ITT     
 las   58169.         0.909        -0.176        -0.461
 las   58170.         1.177        -1.337        -0.833
 las   58171.         1.410        -4.019        -1.078
 las   58172.         1.763        -6.205        -1.593
LAGEOS-1 SGF - ITT  
 lga   58169.         0.950         2.504        -0.553
 lga   58170.         0.835         3.045        -0.385
 lga   58171.         0.611         2.248        -0.653
 lga   58172.         1.242         3.375        -0.973
LAGEOS-1 ITT - JAX  
 lga   58169.        -0.870        -2.728         0.337
 lga   58170.        -0.757        -3.293         0.293
 lga   58171.        -0.539        -3.016         0.403
LAGEOS-1 JAX - SGF  
 lga   58169.        -0.079         0.224         0.216
 lga   58170.        -0.078         0.249         0.092
 lga   58171.        -0.023         0.648         0.144
LAGEOS-2 SGF - ITT  
 lgb   58169.         0.275         3.803        -0.183
 lgb   58170.         0.276         4.929        -0.014
 lgb   58171.         0.074         6.586        -0.038
 lgb   58172.         0.285         7.887         0.218
LAGEOS-2 ITT - JAX  
 lgb   58169.        -0.275        -5.275         0.172
 lgb   58170.        -0.022        -6.584        -0.167
 lgb   58171.        -0.521        -9.161        -0.306
LAGEOS-2 JAX - SGF  
 lgb   58169.         0.000         1.472         0.012
 lgb   58170.        -0.254         1.655         0.181
 lgb   58171.         0.068         2.659         0.258
Stella SGF - ITT    
 ste   58169.         0.623         3.439        -0.179
 ste   58170.         1.022         5.347        -0.444
 ste   58171.         1.762         9.112        -1.159
 ste   58172.         1.403        12.334        -1.082
Starlette SGF - ITT 
 str   58169.         0.432         0.849        -0.787
 str   58170.         0.364         0.655        -0.853
 str   58171.         0.263         0.336        -0.953
 str   58172.         0.245        -0.209        -1.290