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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    
Ajisai ITT - JAX    
Ajisai JAX - SGF    
 aji   58100.        -0.127         0.709         0.039
 aji   58101.        -0.059         0.724         0.006
 aji   58102.        -0.009         0.683         0.013
Beacon-C SGF - ITT  
Cyrosat-2 ESA - ITT 
Etalon-1 SGF - ITT  
Etalon-2 SGF - ITT  
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
Jason-2 CNES - SGF  
Larets SGF - ITT    
LARES SGF - ITT     
LAGEOS-1 SGF - ITT  
LAGEOS-1 ITT - JAX  
LAGEOS-1 JAX - SGF  
 lga   58100.        -0.011         0.027         0.057
 lga   58101.        -0.074         0.243         0.063
 lga   58102.        -0.035         0.146         0.122
LAGEOS-2 SGF - ITT  
LAGEOS-2 ITT - JAX  
LAGEOS-2 JAX - SGF  
 lgb   58100.        -0.039        -0.301         0.044
 lgb   58101.         0.082        -0.433        -0.034
 lgb   58102.        -0.072        -0.540         0.107
Stella SGF - ITT    
Starlette SGF - ITT