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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   58534.         1.066         0.927        -0.899
 aji   58535.         1.190         0.059        -0.875
 aji   58536.         1.163        -0.630        -1.008
 aji   58537.         1.099        -1.643        -1.065
Ajisai ITT - JAX    
 aji   58534.        -1.128        -1.383         0.926
 aji   58535.        -1.241        -0.646         0.869
 aji   58536.        -1.229        -0.110         0.999
Ajisai JAX - SGF    
 aji   58534.         0.063         0.457        -0.027
 aji   58535.         0.051         0.587         0.007
 aji   58536.         0.066         0.740         0.009
Beacon-C SGF - ITT  
 bec   58534.        -0.477        21.123        -8.107
 bec   58535.        -1.753        50.573       -17.264
 bec   58536.        -7.223        96.413       -28.115
 bec   58537.       -17.175       162.031       -39.835
Cyrosat-2 ESA - ITT 
Etalon-1 SGF - ITT  
 eta   58534.         3.639         3.477        -0.751
 eta   58535.         3.188         4.902        -1.985
 eta   58536.         3.869         5.962        -1.624
Etalon-2 SGF - ITT  
 etb   58534.         2.738         4.494        -1.771
 etb   58535.         6.643         5.483        -0.979
 etb   58536.         5.675         8.638        -2.235
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
 jsb   58534.         0.697         7.084        -2.473
 jsb   58535.         2.411        24.652        -3.472
 jsb   58536.         0.684        53.067        -1.761
 jsb   58537.         3.039        89.150        -1.868
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   58534.         0.732         2.423        -0.547
 lar   58535.         0.718         3.991        -0.216
 lar   58536.        -0.324         5.552         0.164
LARES SGF - ITT     
 las   58534.         1.697         1.329        -1.182
 las   58535.         1.591         1.831        -1.507
 las   58536.         1.906         2.950        -2.036
 las   58537.         1.802         3.726        -2.513
LAGEOS-1 SGF - ITT  
 lga   58534.         1.740         2.781        -0.230
 lga   58535.         2.057         3.333        -0.074
 lga   58536.         1.760         3.735        -0.117
 lga   58537.         1.953         4.921        -0.194
LAGEOS-1 ITT - JAX  
 lga   58534.        -1.836        -2.644         0.252
 lga   58535.        -2.049        -3.104        -0.030
 lga   58536.        -2.031        -3.481        -0.009
LAGEOS-1 JAX - SGF  
 lga   58534.         0.096        -0.137        -0.022
 lga   58535.        -0.008        -0.229         0.104
 lga   58536.         0.069        -0.229         0.118
LAGEOS-2 SGF - ITT  
 lgb   58534.         1.459         3.143        -0.544
 lgb   58535.         1.258         4.622        -1.121
 lgb   58536.         1.377         5.113        -0.641
LAGEOS-2 ITT - JAX  
 lgb   58534.        -1.479        -2.960         0.489
 lgb   58535.        -1.247        -4.269         1.128
 lgb   58536.        -1.432        -4.662         0.570
LAGEOS-2 JAX - SGF  
 lgb   58534.         0.020        -0.183         0.055
 lgb   58535.        -0.011        -0.353        -0.008
 lgb   58536.         0.055        -0.450         0.072
Stella SGF - ITT    
 ste   58534.         0.536         0.514         0.128
 ste   58535.         0.444        -1.155         0.143
 ste   58536.         0.727        -2.262        -0.190
Starlette SGF - ITT