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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   58409.         4.671         5.750        -6.534
 aji   58410.         4.882         8.804        -6.557
 aji   58411.         4.734        12.809        -6.512
 aji   58412.         4.830        18.301        -6.639
Ajisai ITT - JAX    
 aji   58409.        -4.682        -6.178         6.624
 aji   58410.        -4.928        -9.480         6.687
 aji   58411.        -4.804       -13.709         6.651
Ajisai JAX - SGF    
 aji   58409.         0.011         0.428        -0.090
 aji   58410.         0.046         0.675        -0.130
 aji   58411.         0.071         0.901        -0.139
Beacon-C SGF - ITT  
 bec   58409.         6.841         3.428        -1.579
 bec   58410.         9.360         5.138         2.994
 bec   58411.        12.143         3.755         8.611
 bec   58412.        16.733         1.682        14.812
Cyrosat-2 ESA - ITT 
 cyb   58409.        11.411         2.912        -8.173
 cyb   58410.        15.391         7.144       -12.257
 cyb   58411.        18.277        16.049       -14.143
 cyb   58412.        24.327        25.561       -18.859
Etalon-1 SGF - ITT  
 eta   58409.        15.020         8.800        -3.990
 eta   58410.        13.366         8.883        -5.781
 eta   58411.        11.749         7.609        -8.630
 eta   58412.        12.623         7.049       -11.807
Etalon-2 SGF - ITT  
 etb   58409.        15.636         6.489       -18.995
 etb   58410.        14.842         7.754       -21.159
 etb   58411.        14.496         8.021       -23.385
 etb   58412.        15.663         8.403       -25.538
Jason-2 SGF - ITT   
 jsb   58409.         4.580        -1.599        -5.194
 jsb   58410.         4.687        -3.622        -7.042
 jsb   58411.         4.572        -5.755        -8.384
 jsb   58412.         5.071        -9.806       -11.038
Jason-2 ITT - CNES  
 jsb   58409.        -2.885         6.333         2.940
 jsb   58410.        -2.221        14.772         4.161
 jsb   58411.        -0.535        24.318         4.479
 jsb   58412.        -1.775        40.949         8.504
Jason-2 CNES - SGF  
 jsb   58409.        -1.695        -4.735         2.254
 jsb   58410.        -2.466       -11.150         2.881
 jsb   58411.        -4.037       -18.563         3.905
 jsb   58412.        -5.696       -28.386         4.637
Larets SGF - ITT    
 lar   58409.         6.771         1.120        -3.010
 lar   58410.         7.804         2.265        -3.629
 lar   58411.         7.603         2.396        -3.479
 lar   58412.         8.454         4.923        -4.316
LARES SGF - ITT     
 las   58409.         6.324         3.089        -3.135
 las   58410.         6.136         4.459        -3.906
 las   58411.         7.362         6.361        -5.518
 las   58412.         8.477         8.238        -7.201
LAGEOS-1 SGF - ITT  
 lga   58409.         9.764         4.207        -1.511
 lga   58410.        10.105         9.358        -3.058
 lga   58411.         8.718        14.272        -2.534
 lga   58412.        11.501        11.933        -4.547
LAGEOS-1 ITT - JAX  
 lga   58409.        -9.829        -4.259         1.614
 lga   58410.       -10.213        -9.657         3.191
 lga   58411.        -8.755       -14.754         2.615
LAGEOS-1 JAX - SGF  
 lga   58409.         0.066         0.052        -0.103
 lga   58410.         0.108         0.299        -0.133
 lga   58411.         0.037         0.482        -0.081
LAGEOS-2 SGF - ITT  
 lgb   58409.         5.673         0.236        -4.207
 lgb   58410.         5.896        -1.773        -5.046
 lgb   58411.         5.251        -3.869        -5.194
 lgb   58412.         5.978        -6.678        -4.624
LAGEOS-2 ITT - JAX  
 lgb   58409.        -5.676        -0.584         4.043
 lgb   58410.        -5.788         1.298         4.879
 lgb   58411.        -6.091         3.289         5.304
LAGEOS-2 JAX - SGF  
 lgb   58409.         0.002         0.348         0.165
 lgb   58410.        -0.108         0.475         0.168
 lgb   58411.        -0.029         0.582         0.227
Stella SGF - ITT    
 ste   58409.         5.930         2.726        -3.059
 ste   58410.         6.137         3.920        -3.552
 ste   58411.         6.961         6.837        -4.663
 ste   58412.         6.585         9.820        -5.040
Starlette SGF - ITT 
 str   58409.         3.339         1.628        -4.122
 str   58410.         3.394         2.028        -4.291
 str   58411.         3.267         2.465        -4.517
 str   58412.         3.126         3.818        -4.497