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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   58595.         1.184         1.662        -1.434
 aji   58596.         1.341         2.762        -1.580
 aji   58597.         1.290         4.019        -1.706
 aji   58598.         1.131         5.466        -1.819
Ajisai ITT - JAX    
 aji   58595.        -1.243        -1.378         1.581
 aji   58596.        -1.397        -2.313         1.763
 aji   58597.        -1.343        -3.412         1.902
Ajisai JAX - SGF    
 aji   58595.         0.060        -0.285        -0.147
 aji   58596.         0.056        -0.449        -0.182
 aji   58597.         0.053        -0.607        -0.195
Beacon-C SGF - ITT  
 bec   58595.         1.433        -9.913        -0.396
 bec   58596.         0.967       -15.524         0.078
 bec   58597.         0.152       -21.721         0.936
 bec   58598.         1.342       -28.697        -0.949
Cyrosat-2 ESA - ITT 
 cyb   58595.         1.797        -0.693         0.458
 cyb   58596.         1.224        -1.206         0.703
 cyb   58597.         2.688        -1.802        -0.925
 cyb   58598.         1.811        -2.161        -1.011
Etalon-1 SGF - ITT  
 eta   58595.         5.170        -1.701        -5.008
 eta   58596.         5.056        -0.656        -6.200
 eta   58597.         5.765         0.341        -8.346
 eta   58598.         3.462        -0.912        -3.933
Etalon-2 SGF - ITT  
 etb   58595.         5.624         3.161        -1.856
 etb   58596.         5.967         1.950        -2.254
 etb   58597.         5.969         3.861        -2.269
 etb   58598.         6.327         5.608        -2.580
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   58595.         1.729        -0.269        -1.032
 lar   58596.         1.865        -0.204        -1.142
 lar   58597.         1.890        -0.187        -1.210
 lar   58598.         1.983        -0.484        -1.442
LARES SGF - ITT     
 las   58595.         1.845        -1.648        -0.954
 las   58596.         1.940        -2.259        -1.143
 las   58597.         1.783        -3.048        -1.203
 las   58598.         2.275        -4.031        -1.629
LAGEOS-1 SGF - ITT  
 lga   58595.         2.656         0.345        -0.152
 lga   58596.         3.315         0.643        -0.666
 lga   58597.         2.541         1.110        -0.177
 lga   58598.         2.573         1.039         0.128
LAGEOS-1 ITT - JAX  
 lga   58595.        -2.663        -0.316         0.218
 lga   58596.        -3.347        -0.577         0.750
 lga   58597.        -2.548        -1.029         0.263
LAGEOS-1 JAX - SGF  
 lga   58595.         0.007        -0.029        -0.066
 lga   58596.         0.032        -0.066        -0.084
 lga   58597.         0.007        -0.081        -0.086
LAGEOS-2 SGF - ITT  
 lgb   58595.         1.760         2.301        -1.311
 lgb   58596.         1.517         3.755        -1.557
 lgb   58597.         1.872         4.525        -1.432
 lgb   58598.         1.278         5.851        -1.505
LAGEOS-2 ITT - JAX  
 lgb   58595.        -1.665        -2.967         1.285
 lgb   58596.        -1.339        -4.771         1.472
 lgb   58597.        -2.055        -6.047         1.471
LAGEOS-2 JAX - SGF  
 lgb   58595.        -0.096         0.666         0.026
 lgb   58596.        -0.177         1.016         0.085
 lgb   58597.        -0.035         1.505         0.059
Stella SGF - ITT    
 ste   58595.         1.226        -2.869        -1.641
 ste   58596.         1.618        -4.150        -2.252
 ste   58597.         1.425        -4.650        -2.193
 ste   58598.         1.379        -5.991        -2.538
Starlette SGF - ITT