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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   58902.         0.678         0.528        -0.741
 aji   58903.         0.964         0.227        -0.933
 aji   58904.         0.715        -0.759        -0.741
 aji   58905.         0.893        -1.918        -0.651
Ajisai ITT - JAX    
 aji   58902.        -0.754        -0.353         0.987
 aji   58903.        -1.023        -0.155         1.243
 aji   58904.        -0.980         0.474         1.243
Ajisai JAX - SGF    
 aji   58902.         0.076        -0.175        -0.246
 aji   58903.         0.059        -0.071        -0.310
 aji   58904.         0.010         0.086        -0.340
Beacon-C SGF - ITT  
 bec   58902.         0.843        -2.111        -0.008
 bec   58903.         1.575        -2.944         0.756
 bec   58904.         1.740        -3.487         1.218
 bec   58905.         2.026        -2.239         1.317
Cyrosat-2 ESA - ITT 
Etalon-1 SGF - ITT  
 eta   58902.         1.776         4.678        -1.128
 eta   58903.         1.073         3.805        -0.631
 eta   58904.         2.147         4.707        -0.692
Etalon-2 SGF - ITT  
 etb   58902.         2.168         3.778        -0.877
 etb   58903.         3.665         4.373        -1.848
 etb   58904.         3.746         5.911        -1.802
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   58902.         0.927        -0.022         0.926
 lar   58903.         0.828         0.061         1.443
 lar   58904.         0.763         0.199         1.923
 lar   58905.         0.472         0.644         2.681
LARES SGF - ITT     
 las   58902.         1.018        -0.066         0.141
 las   58903.         1.098        -0.879         0.027
 las   58904.         1.058        -1.720        -0.059
 las   58905.         1.154        -3.376        -0.336
LAGEOS-1 SGF - ITT  
 lga   58902.         1.416         2.206         0.706
 lga   58903.         1.603         2.780         1.081
 lga   58904.         1.529         3.305         1.347
 lga   58905.         1.241         3.659         1.360
LAGEOS-1 ITT - JAX  
 lga   58902.        -1.424        -1.991        -0.621
 lga   58903.        -1.609        -2.491        -1.023
 lga   58904.        -1.451        -3.049        -1.282
LAGEOS-1 JAX - SGF  
 lga   58902.         0.009        -0.216        -0.084
 lga   58903.         0.005        -0.289        -0.058
 lga   58904.        -0.078        -0.256        -0.065
LAGEOS-2 SGF - ITT  
 lgb   58902.         1.059         1.333        -0.728
 lgb   58903.         1.268         1.594         0.350
 lgb   58904.         0.981         1.399        -0.520
 lgb   58905.         1.004         1.040        -0.865
LAGEOS-2 ITT - JAX  
 lgb   58902.        -0.988        -2.347         0.893
 lgb   58903.        -1.587        -2.863         0.059
 lgb   58904.        -0.881        -3.372         0.684
LAGEOS-2 JAX - SGF  
 lgb   58902.        -0.070         1.015        -0.165
 lgb   58903.         0.318         1.269        -0.409
 lgb   58904.        -0.100         1.974        -0.164
Stella SGF - ITT    
 ste   58902.         0.878         0.256         0.157
 ste   58903.         1.222        -0.059        -0.073
 ste   58904.         1.272         0.367        -0.156
 ste   58905.         1.305         0.839        -0.211
Starlette SGF - ITT 
 str   58902.         0.756        -0.162        -1.911
 str   58903.         0.839        -0.353        -1.984
 str   58904.         0.639        -0.188        -2.025
 str   58905.         0.617        -0.259        -1.889