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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   58865.         1.875         0.181        -1.789
 aji   58866.         1.885        -0.762        -1.764
 aji   58867.         1.869        -2.247        -1.565
 aji   58868.         1.663        -3.600        -1.278
Ajisai ITT - JAX    
 aji   58865.        -1.902        -0.478         1.871
 aji   58866.        -1.913         0.409         1.807
 aji   58867.        -1.924         1.825         1.618
Ajisai JAX - SGF    
 aji   58865.         0.027         0.297        -0.082
 aji   58866.         0.028         0.353        -0.043
 aji   58867.         0.055         0.421        -0.053
Beacon-C SGF - ITT  
 bec   58865.         0.325        -5.223        -2.113
 bec   58866.        -1.221       -11.018        -1.340
 bec   58867.        -1.783       -22.092        -2.027
 bec   58868.        -1.485       -35.644        -2.646
Cyrosat-2 ESA - ITT 
Etalon-1 SGF - ITT  
 eta   58865.       -22.615        24.176      -131.925
 eta   58866.        35.144        84.253      -126.474
 eta   58867.        48.158       118.219      -133.092
 eta   58868.        69.797       153.753      -137.344
Etalon-2 SGF - ITT  
 etb   58865.        -1.213        14.440        -1.022
 etb   58866.         0.647        15.599        -4.755
 etb   58867.         5.615        18.570        -9.653
 etb   58868.        12.679        26.493       -13.483
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   58865.         2.187         1.055        -1.465
 lar   58866.         2.464         0.301        -2.059
 lar   58867.         2.342        -0.808        -2.188
 lar   58868.         3.121        -2.047        -3.438
LARES SGF - ITT     
 las   58865.         1.325         1.146        -0.532
 las   58866.         1.234         0.988        -0.927
 las   58867.         1.306         0.210        -1.388
 las   58868.         1.331        -0.343        -1.923
LAGEOS-1 SGF - ITT  
 lga   58865.         2.605         3.458        -1.093
 lga   58866.         2.691         3.397        -1.840
 lga   58867.         2.647         3.898        -1.674
 lga   58868.         2.379         3.886        -2.137
LAGEOS-1 ITT - JAX  
 lga   58865.        -2.645        -3.534         1.098
 lga   58866.        -2.690        -3.585         1.797
 lga   58867.        -2.678        -3.980         1.935
LAGEOS-1 JAX - SGF  
 lga   58865.         0.040         0.076        -0.004
 lga   58866.        -0.001         0.188         0.043
 lga   58867.        -0.040         0.273         0.014
LAGEOS-2 SGF - ITT  
 lgb   58865.         1.662        -1.004        -1.623
 lgb   58866.         3.101        -2.989        -3.564
 lgb   58867.         0.523        -6.118        -1.562
 lgb   58868.         3.949        -8.865        -3.973
LAGEOS-2 ITT - JAX  
 lgb   58865.        -1.659         1.105         1.477
 lgb   58866.        -3.139         3.172         3.399
 lgb   58867.        -0.580         6.394         2.340
LAGEOS-2 JAX - SGF  
 lgb   58865.        -0.004        -0.101         0.146
 lgb   58866.         0.038        -0.184         0.165
 lgb   58867.        -0.047        -0.374         0.201
Stella SGF - ITT    
 ste   58865.         1.345         1.691        -0.637
 ste   58866.         1.004         0.693        -0.442
 ste   58867.         0.809        -0.978        -0.470
 ste   58868.         0.491        -3.708        -0.329
Starlette SGF - ITT 
 str   58865.         1.665        -0.833        -3.520
 str   58866.         1.452        -2.919        -3.168
 str   58867.         1.445        -6.301        -3.842
 str   58868.         1.403       -11.718        -4.313