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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   57929.         2.382        -2.591        -1.989
 aji   57930.         3.103        -4.452        -2.298
 aji   57931.         2.332        -7.168        -1.470
 aji   57932.         3.525       -11.090        -2.232
Ajisai ITT - JAX    
 aji   57929.        -2.291         3.102         2.039
 aji   57930.        -3.175         5.440         2.569
 aji   57931.        -2.236         9.049         1.731
Ajisai JAX - SGF    
 aji   57929.        -0.091        -0.511        -0.050
 aji   57930.         0.072        -0.988        -0.271
 aji   57931.        -0.096        -1.881        -0.261
Beacon-C SGF - ITT  
 bec   57929.         3.369        -2.972        -3.004
 bec   57930.         3.811       -13.671        -2.221
 bec   57931.         4.172       -33.112        -0.907
 bec   57932.         6.368       -61.856        -0.568
Cyrosat-2 ESA - ITT 
 cyb   57929.         9.460        -1.693        -6.671
 cyb   57930.        14.323         2.914       -12.941
 cyb   57931.        22.056        15.945       -20.042
 cyb   57932.        32.982        25.314       -26.838
Etalon-1 SGF - ITT  
 eta   57929.        10.074        -7.182       -10.175
 eta   57930.        10.759        -9.429        -5.248
 eta   57931.        11.911        -7.693         0.665
 eta   57932.        14.685        -3.544       -10.641
Etalon-2 SGF - ITT  
 etb   57929.        12.249        -6.736        -6.215
 etb   57930.         9.236        -4.005        -7.435
 etb   57931.         7.719        -3.043        -5.639
 etb   57932.        14.806        -6.940       -12.824
Jason-2 SGF - ITT   
 jsb   57929.         4.653       -14.981        -2.332
 jsb   57930.         4.504       -32.151        -4.102
 jsb   57931.        11.777       -61.303        -6.432
 jsb   57932.         2.634       -91.407        -0.898
Jason-2 ITT - CNES  
 jsb   57929.        -0.573         9.955        -4.361
 jsb   57930.         0.873        21.235        -5.903
 jsb   57931.        -2.573        42.199        -6.688
 jsb   57932.         3.742        63.396       -12.931
Jason-2 CNES - SGF  
 jsb   57929.        -4.081         5.025         6.693
 jsb   57930.        -5.377        10.917        10.005
 jsb   57931.        -9.203        19.104        13.120
 jsb   57932.        -6.376        28.011        13.829
Larets SGF - ITT    
 lar   57929.         2.894        -2.340        -1.176
 lar   57930.         4.164        -2.492        -2.014
 lar   57931.         3.213        -0.412        -1.168
 lar   57932.         1.527         3.038         0.505
LARES SGF - ITT     
 las   57929.         6.771       -10.094        -6.954
 las   57930.         8.584       -19.439        -8.804
 las   57931.         7.214       -31.753       -12.661
 las   57932.        14.904       -47.425       -16.497
LAGEOS-1 SGF - ITT  
 lga   57929.         7.959        -1.111        -2.111
 lga   57930.         6.518        -0.016        -1.977
 lga   57931.         8.278         6.999        -0.552
 lga   57932.        13.762        12.714        -7.094
LAGEOS-1 ITT - JAX  
 lga   57929.        -7.937         1.159         2.136
 lga   57930.        -6.529         0.055         2.011
 lga   57931.        -8.256        -6.900         0.613
LAGEOS-1 JAX - SGF  
 lga   57929.        -0.021        -0.048        -0.025
 lga   57930.         0.011        -0.038        -0.034
 lga   57931.        -0.022        -0.099        -0.061
LAGEOS-2 SGF - ITT  
 lgb   57929.         4.050        -2.124        -1.919
 lgb   57930.         4.366        -4.088        -4.220
 lgb   57931.         4.879        -6.637        -2.129
 lgb   57932.         5.001       -10.431        -4.577
LAGEOS-2 ITT - JAX  
 lgb   57929.        -3.779         1.113         1.875
 lgb   57930.        -4.481         2.538         4.044
 lgb   57931.        -4.525         4.620         2.193
LAGEOS-2 JAX - SGF  
 lgb   57929.        -0.271         1.010         0.044
 lgb   57930.         0.115         1.549         0.176
 lgb   57931.        -0.354         2.017        -0.064
Stella SGF - ITT    
 ste   57929.         4.676        -0.181        -2.398
 ste   57930.         5.826         2.635        -3.574
 ste   57931.         7.508         8.428        -5.086
 ste   57932.         7.580        15.969        -5.946
Starlette SGF - ITT 
 str   57929.         2.193        -0.499        -1.746
 str   57930.         2.622         2.186        -1.706
 str   57931.         2.838         6.646        -1.996
 str   57932.         3.360        13.127        -2.312