Home » Quality Checks » CPF Comparison

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   58350.         3.849         4.353        -3.249
 aji   58351.         3.628         6.629        -3.167
 aji   58352.         3.784         9.468        -3.058
 aji   58353.         3.922        12.171        -2.910
Ajisai ITT - JAX    
 aji   58350.        -3.834        -4.155         3.279
 aji   58351.        -3.660        -6.491         3.278
 aji   58352.        -3.719        -9.480         3.096
Ajisai JAX - SGF    
 aji   58350.        -0.015        -0.197        -0.031
 aji   58351.         0.032        -0.138        -0.111
 aji   58352.        -0.065         0.012        -0.038
Beacon-C SGF - ITT  
 bec   58350.         4.019         7.171         5.567
 bec   58351.         4.622        12.366        10.155
 bec   58352.         4.827        18.226        15.256
 bec   58353.         5.188        23.017        20.143
Cyrosat-2 ESA - ITT 
 cyb   58350.         6.608        -1.526       -13.281
 cyb   58351.         9.305        -1.521       -19.704
 cyb   58352.         7.992        -1.694       -23.769
 cyb   58353.         9.475        -2.743       -31.952
Etalon-1 SGF - ITT  
 eta   58350.        14.499        -4.780        -7.709
 eta   58351.        17.347        -4.446        -7.529
 eta   58352.        18.281        -2.800        -7.171
 eta   58353.        17.530        -0.432        -6.991
Etalon-2 SGF - ITT  
 etb   58350.        14.365         4.081        -4.479
 etb   58351.        13.499         6.241        -5.050
 etb   58352.        11.512         7.424        -4.781
 etb   58353.        12.832         7.633        -2.947
Jason-2 SGF - ITT   
 jsb   58350.         2.678         5.713        -0.958
 jsb   58351.         2.420        12.208        -1.486
 jsb   58352.         3.237        19.781        -3.480
 jsb   58353.         1.037        28.100        -4.000
Jason-2 ITT - CNES  
 jsb   58350.        -3.727        -5.748        -0.455
 jsb   58351.        -4.176        -9.685        -0.499
 jsb   58352.        -5.422       -13.432         0.315
 jsb   58353.        -4.786       -17.474         0.527
Jason-2 CNES - SGF  
 jsb   58350.         1.049         0.035         1.413
 jsb   58351.         1.756        -2.523         1.986
 jsb   58352.         2.185        -6.350         3.165
 jsb   58353.         3.749       -10.625         3.473
Larets SGF - ITT    
 lar   58350.         7.371        -0.587        -8.045
 lar   58351.         7.514         2.550        -9.455
 lar   58352.         8.034         6.199        -9.946
 lar   58353.         6.720        10.614       -10.212
LARES SGF - ITT     
 las   58350.         5.402        -1.097        -3.658
 las   58351.         5.351        -0.980        -4.217
 las   58352.         5.748        -0.780        -4.749
 las   58353.         5.805        -0.281        -5.554
LAGEOS-1 SGF - ITT  
 lga   58350.         8.030        -0.485        -2.224
 lga   58351.         8.152        -1.121        -2.423
 lga   58352.         7.545         0.236        -1.126
 lga   58353.         7.924        -1.768        -2.828
LAGEOS-1 ITT - JAX  
 lga   58350.        -8.130         0.274         2.223
 lga   58351.        -8.152         0.687         2.383
 lga   58352.        -7.855        -0.230         1.500
LAGEOS-1 JAX - SGF  
 lga   58350.         0.099         0.211         0.000
 lga   58351.         0.000         0.434         0.040
 lga   58352.         0.183         0.441        -0.249
LAGEOS-2 SGF - ITT  
 lgb   58350.         5.777         2.193        -4.728
 lgb   58351.         5.705         3.824        -2.982
 lgb   58352.         5.983         4.706        -4.130
 lgb   58353.         5.519         5.920        -2.137
LAGEOS-2 ITT - JAX  
 lgb   58350.        -5.605        -3.399         4.767
 lgb   58351.        -5.661        -5.002         3.153
 lgb   58352.        -6.018        -6.937         4.267
LAGEOS-2 JAX - SGF  
 lgb   58350.        -0.173         1.206        -0.039
 lgb   58351.        -0.044         1.178        -0.171
 lgb   58352.        -0.065         1.935         0.109
Stella SGF - ITT    
 ste   58350.         6.823         3.322        -3.663
 ste   58351.         8.077         8.154        -4.922
 ste   58352.         7.814        13.049        -4.898
 ste   58353.         8.159        16.732        -5.083
Starlette SGF - ITT 
 str   58350.         3.803        -1.809        -4.135
 str   58351.         3.862        -6.971        -4.603
 str   58352.         3.302       -14.512        -4.889
 str   58353.         5.549       -24.205        -4.967