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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   58827.         2.609         1.774        -3.333
 aji   58828.         2.764         1.068        -3.775
 aji   58829.         2.435         0.400        -3.159
 aji   58830.         2.756        -0.806        -4.076
Ajisai ITT - JAX    
 aji   58827.        -2.604        -0.957         3.091
 aji   58828.        -2.870         0.608         3.566
 aji   58829.        -2.727         2.411         3.400
Ajisai JAX - SGF    
 aji   58827.        -0.006        -0.817         0.242
 aji   58828.         0.106        -1.676         0.209
 aji   58829.         0.016        -2.633         0.261
Beacon-C SGF - ITT  
 bec   58827.         1.824        -1.793        -4.056
 bec   58828.         2.367        -7.304        -4.482
 bec   58829.         2.598       -16.397        -4.132
 bec   58830.         1.909       -30.854        -2.828
Cyrosat-2 ESA - ITT 
Etalon-1 SGF - ITT  
 eta   58827.         8.317         7.008         0.035
 eta   58828.         7.381         6.387        -0.860
 eta   58829.         7.125         6.435        -1.229
 eta   58830.         6.870         6.608        -1.976
Etalon-2 SGF - ITT  
 etb   58827.        10.859       131.284        -2.595
 etb   58828.        15.159       141.205       -20.928
 etb   58829.        56.674       160.445        -0.717
 etb   58830.         5.323       166.470       -66.192
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   58827.         2.908         1.933        -0.765
 lar   58828.         2.672         1.070        -0.710
 lar   58829.         2.584        -0.069        -0.754
 lar   58830.         2.269        -1.637        -0.534
LARES SGF - ITT     
 las   58827.         3.390         2.639        -2.510
 las   58828.         3.579         2.007        -2.949
 las   58829.         3.906         0.996        -3.933
 las   58830.         3.692        -0.012        -4.308
LAGEOS-1 SGF - ITT  
 lga   58827.         4.408         4.736        -0.398
 lga   58828.         4.102         5.461        -0.458
 lga   58829.         4.754         6.442         0.159
 lga   58830.         3.786         7.123         0.658
LAGEOS-1 ITT - JAX  
 lga   58827.        -4.428        -4.694         0.393
 lga   58828.        -4.117        -5.406         0.415
 lga   58829.        -4.726        -6.358        -0.181
LAGEOS-1 JAX - SGF  
 lga   58827.         0.020        -0.042         0.006
 lga   58828.         0.014        -0.055         0.043
 lga   58829.        -0.028        -0.084         0.022
LAGEOS-2 SGF - ITT  
 lgb   58827.         3.666         0.767        -2.504
 lgb   58828.         4.393        -0.025        -3.463
 lgb   58829.         3.318        -3.557        -2.219
 lgb   58830.         5.013        -4.035        -3.780
LAGEOS-2 ITT - JAX  
 lgb   58827.        -3.604        -1.334         2.433
 lgb   58828.        -4.204        -0.624         3.290
 lgb   58829.        -3.278         2.318         2.633
LAGEOS-2 JAX - SGF  
 lgb   58827.        -0.062         0.567         0.071
 lgb   58828.        -0.188         0.649         0.173
 lgb   58829.         0.038         1.126         0.095
Stella SGF - ITT    
 ste   58827.         3.147         3.476        -1.322
 ste   58828.         3.399         4.792        -1.639
 ste   58829.         3.542         6.125        -1.610
 ste   58830.         3.472         7.906        -1.824
Starlette SGF - ITT 
 str   58827.         2.119         0.936        -2.668
 str   58828.         2.149         0.876        -2.914
 str   58829.         2.045         0.219        -2.927
 str   58830.         2.167         0.699        -2.988