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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   59045.         4.073         1.407        -3.140
 aji   59046.         4.277         2.892        -3.032
 aji   59047.         4.439         4.809        -2.927
 aji   59048.         4.367         6.849        -2.583
Ajisai ITT - JAX    
 aji   59045.        -3.958        -0.833         2.868
 aji   59046.        -4.155        -1.262         2.626
 aji   59047.        -4.311        -1.837         2.475
Ajisai JAX - SGF    
 aji   59045.        -0.115        -0.573         0.272
 aji   59046.        -0.122        -1.630         0.406
 aji   59047.        -0.128        -2.972         0.451
Beacon-C SGF - ITT  
 bec   59045.         2.357         2.465        -0.772
 bec   59046.         1.562         9.423         0.955
 bec   59047.         2.052        21.217         1.930
 bec   59048.         4.544        40.010         3.754
Cyrosat-2 ESA - ITT 
Etalon-1 SGF - ITT  
 eta   59045.        13.039        -1.778         3.551
 eta   59046.        14.733         0.368         6.172
 eta   59047.        14.999         3.544         4.811
 eta   59048.        13.964        -0.686         5.773
Etalon-2 SGF - ITT  
 etb   59045.        10.145        -6.459        -1.885
 etb   59046.        10.697       -11.210        -6.441
 etb   59047.        10.965       -13.470        -7.545
 etb   59048.        12.831       -15.583        -7.313
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   59045.         4.677        -2.925        -0.809
 lar   59046.         4.798        -4.094        -0.656
 lar   59047.         4.775        -4.731        -0.540
 lar   59048.         5.518        -5.982        -1.006
LARES SGF - ITT     
 las   59045.         5.732         1.940         0.137
 las   59046.         5.896         4.476         1.922
 las   59047.         6.353         8.503         3.778
 las   59048.         6.275        11.845         6.695
LAGEOS-1 SGF - ITT  
 lga   59045.         7.935        -1.102        -0.195
 lga   59046.         8.501        -0.376        -0.768
 lga   59047.         7.084         0.500         1.118
 lga   59048.         9.434         2.557        -0.588
LAGEOS-1 ITT - JAX  
 lga   59045.        -7.935         1.148         0.253
 lga   59046.        -8.504         0.412         0.836
 lga   59047.        -7.096        -0.476        -1.034
LAGEOS-1 JAX - SGF  
 lga   59045.         0.000        -0.047        -0.059
 lga   59046.         0.003        -0.036        -0.069
 lga   59047.         0.011        -0.024        -0.084
LAGEOS-2 SGF - ITT  
 lgb   59045.         5.817        -0.176        -4.722
 lgb   59046.         5.849        -1.062        -5.071
 lgb   59047.         6.013        -1.440        -4.755
 lgb   59048.         5.979        -2.366        -5.364
LAGEOS-2 ITT - JAX  
 lgb   59045.        -5.652        -0.538         4.700
 lgb   59046.        -5.941        -0.191         5.080
 lgb   59047.        -5.717        -0.053         4.749
LAGEOS-2 JAX - SGF  
 lgb   59045.        -0.164         0.714         0.022
 lgb   59046.         0.091         1.254        -0.010
 lgb   59047.        -0.296         1.493         0.007
Stella SGF - ITT    
 ste   59045.         5.766         0.950        -2.116
 ste   59046.         6.150         3.320        -1.941
 ste   59047.         6.413         6.788        -1.741
 ste   59048.         6.523        11.032        -1.896
Starlette SGF - ITT 
 str   59045.         3.054         3.096        -4.113
 str   59046.         3.031         6.113        -4.120
 str   59047.         3.351        11.072        -4.654
 str   59048.         2.723        17.563        -4.451