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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   59809.         5.677        -5.235        -6.533
 aji   59810.         5.483        -9.940        -5.868
 aji   59811.         5.622       -17.602        -6.054
 aji   59812.         5.370       -24.441        -5.857
Ajisai ITT - JAX    
Ajisai JAX - SGF    
Ajisai SGF - DGF    
 aji   59809.         0.214        -0.353         0.498
 aji   59810.         0.287        -0.006         0.881
 aji   59811.         0.495         0.795         1.131
 aji   59812.         0.556         1.890         1.395
Ajisai ITT - DGF    
 aji   59809.        -5.463         4.882         7.031
 aji   59810.        -5.196         9.933         6.749
 aji   59811.        -5.127        18.397         7.185
 aji   59812.        -4.821        26.367         7.243
Beacon-C SGF - ITT  
 bec   59809.         6.778       -48.462       -31.073
 bec   59810.         9.348      -100.495       -48.721
 bec   59811.        -3.214      -180.851       -58.385
 bec   59812.         8.851      -295.906       -84.015
Cyrosat-2 ESA - ITT 
Etalon-1 SGF - ITT  
 eta   59809.        11.554       -39.840       -39.677
 eta   59810.        20.478       -47.796       -70.407
 eta   59811.        21.948       -57.657       -87.770
Etalon-1 SGF - DGF  
 eta   59809.        -0.016        -0.332         0.635
 eta   59810.         0.162        -0.423         0.837
 eta   59811.         0.298        -0.383         1.054
Etalon-1 ITT - DGF  
 eta   59809.       -11.570        39.509        40.312
 eta   59810.       -20.317        47.373        71.244
 eta   59811.       -21.650        57.274        88.824
 eta   59812.       -31.194        70.860       100.794
Etalon-2 SGF - ITT  
 etb   59809.        47.695        -2.381        53.630
 etb   59810.        -8.505       -49.596        44.627
 etb   59811.        -6.808       -65.939        47.767
Etalon-2 SGF - DGF  
 etb   59809.         0.096         0.134         0.446
 etb   59810.        -0.035         0.056         0.417
 etb   59811.        -0.061         0.003         0.430
Etalon-2 ITT - DGF  
 etb   59809.       -47.599         2.514       -53.184
 etb   59810.         8.469        49.652       -44.210
 etb   59811.         6.747        65.943       -47.337
 etb   59812.         4.383        75.135       -54.055
Larets SGF - ITT    
 lar   59809.         9.564       -11.430        -0.941
 lar   59810.         7.414       -19.126         2.699
 lar   59811.        12.328       -24.597         2.004
 lar   59812.         8.518       -34.358         4.327
Larets SGF - DGF    
 lar   59809.         3.151       -13.749        -2.612
 lar   59810.        -0.167       -23.549         0.025
 lar   59811.         6.443       -29.658        -3.445
 lar   59812.         0.918       -41.206        -2.499
Larets ITT - DGF    
 lar   59809.        -6.413        -2.319        -1.670
 lar   59810.        -7.581        -4.423        -2.675
 lar   59811.        -5.885        -5.061        -5.449
 lar   59812.        -7.600        -6.848        -6.826
LARES SGF - ITT     
 las   59809.         9.863       -14.683        -4.084
 las   59810.         8.370       -24.512        -2.276
 las   59811.        11.946       -36.656        -4.281
 las   59812.        10.006       -49.512        -4.804
LARES SGF - DGF     
 las   59809.         0.152        -0.400         0.205
 las   59810.         0.035        -0.914         0.450
 las   59811.         0.262        -1.484         0.350
 las   59812.        -0.085        -2.206         0.752
LARES ITT - DGF     
 las   59809.        -9.711        14.283         4.289
 las   59810.        -8.335        23.598         2.727
 las   59811.       -11.684        35.172         4.631
 las   59812.        -9.911        47.297         5.184
LAGEOS-1 SGF - ITT  
 lga   59809.        13.081        -1.308        -6.194
 lga   59810.        13.875        -3.004        -4.643
 lga   59811.        13.919        -6.880        -7.609
 lga   59812.        14.272        -5.647        -7.333
LAGEOS-1 ITT - JAX  
LAGEOS-1 JAX - SGF  
LAGEOS-1 SGF - DGF  
 lga   59809.         0.006        -0.198         0.019
 lga   59810.         0.068        -0.245         0.022
 lga   59811.         0.002        -0.327        -0.016
 lga   59812.         0.036        -0.368        -0.010
LAGEOS-2 SGF - ITT  
 lgb   59809.        10.815         6.938        -9.870
 lgb   59810.        10.672         8.881        -8.913
 lgb   59811.        12.120        14.229       -10.373
 lgb   59812.         9.066        19.157        -9.168
LAGEOS-2 ITT - JAX  
LAGEOS-2 JAX - SGF  
LAGEOS-2 SGF - DGF  
 lgb   59809.        -0.061        -0.252         0.103
 lgb   59810.        -0.065        -0.417         0.109
 lgb   59811.        -0.170        -0.864         0.213
 lgb   59812.         0.031        -1.329         0.042
Stella SGF - ITT    
 ste   59809.         9.863         1.788        -8.059
 ste   59810.        10.577         6.094        -8.835
 ste   59811.        10.708        11.894        -9.362
 ste   59812.        11.168        16.957        -9.771
Stella SGF - DGF    
 ste   59809.        -0.689        -1.696         0.202
 ste   59810.        -0.929        -3.733         0.216
 ste   59811.        -0.874        -6.500         0.051
 ste   59812.        -0.711        -8.303        -0.205
Stella ITT - DGF    
 ste   59809.       -10.552        -3.483         8.261
 ste   59810.       -11.506        -9.827         9.050
 ste   59811.       -11.582       -18.394         9.413
 ste   59812.       -11.880       -25.260         9.566
Starlette SGF - ITT 
 str   59809.         7.090        -7.357        -8.614
 str   59810.         8.107       -15.848        -9.461
 str   59811.         8.063       -25.678        -8.789
 str   59812.         9.902       -36.667        -9.655
Starlette SGF - DGF 
 str   59809.        -0.158        -0.101         0.009
 str   59810.        -0.156         0.022        -0.041
 str   59811.        -0.162         0.101        -0.044
 str   59812.        -0.123         0.048        -0.094
Starlette ITT - DGF 
 str   59809.        -7.248         7.256         8.623
 str   59810.        -8.262        15.870         9.420
 str   59811.        -8.226        25.779         8.745
 str   59812.       -10.012        36.720         9.564