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   58654.         2.852        -1.696        -4.576
 aji   58655.         2.624        -2.070        -4.696
 aji   58656.         2.800        -3.476        -5.314
 aji   58657.         2.818        -4.165        -5.256
Ajisai ITT - JAX    
 aji   58654.        -2.841         1.162         4.479
 aji   58655.        -2.654         1.319         4.585
 aji   58656.        -2.753         2.522         5.091
Ajisai JAX - SGF    
 aji   58654.        -0.011         0.535         0.097
 aji   58655.         0.030         0.752         0.111
 aji   58656.        -0.047         0.954         0.222
Beacon-C SGF - ITT  
 bec   58654.         2.139        -1.709        -0.929
 bec   58655.         2.166        -4.619        -0.520
 bec   58656.         1.928        -7.858         0.084
 bec   58657.         2.265       -12.811         1.001
Cyrosat-2 ESA - ITT 
Etalon-1 SGF - ITT  
 eta   58654.         9.284         1.969         2.349
 eta   58655.         9.907         3.559         3.514
 eta   58656.         8.576         4.731         5.491
 eta   58657.         7.728         4.337         7.919
Etalon-2 SGF - ITT  
 etb   58654.         8.210         3.473        -1.952
 etb   58655.         7.764         4.268        -1.946
 etb   58656.         7.555         4.335        -1.201
 etb   58657.         7.751         5.727        -1.722
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   58654.         4.093        -3.874        -3.460
 lar   58655.         3.708        -4.449        -3.621
 lar   58656.         4.223        -5.630        -3.975
 lar   58657.         4.501        -7.425        -4.551
LARES SGF - ITT     
 las   58654.         4.563         0.425        -1.638
 las   58655.         5.043         1.890        -1.781
 las   58656.         4.882         3.932        -1.382
 las   58657.         5.580         5.249        -1.677
LAGEOS-1 SGF - ITT  
 lga   58654.         6.618        -1.273        -1.313
 lga   58655.         7.038        -2.951        -0.001
 lga   58656.         7.333        -3.010        -2.616
 lga   58657.         6.418        -2.249         0.038
LAGEOS-1 ITT - JAX  
 lga   58654.        -6.625         1.336         1.286
 lga   58655.        -7.024         2.964        -0.016
 lga   58656.        -7.312         3.026         2.524
LAGEOS-1 JAX - SGF  
 lga   58654.         0.008        -0.063         0.027
 lga   58655.        -0.013        -0.013         0.016
 lga   58656.        -0.021        -0.016         0.093
LAGEOS-2 SGF - ITT  
 lgb   58654.         4.571        -0.793        -5.718
 lgb   58655.         4.416        -1.087        -6.210
 lgb   58656.         4.695        -0.765        -6.220
 lgb   58657.         4.321        -1.226        -7.070
LAGEOS-2 ITT - JAX  
 lgb   58654.        -4.518         0.919         5.625
 lgb   58655.        -4.404         1.340         6.122
 lgb   58656.        -4.690         1.370         6.167
LAGEOS-2 JAX - SGF  
 lgb   58654.        -0.053        -0.126         0.093
 lgb   58655.        -0.012        -0.253         0.088
 lgb   58656.        -0.060        -0.307         0.091
Stella SGF - ITT    
 ste   58654.         5.160         1.617        -4.175
 ste   58655.         5.471         3.353        -4.851
 ste   58656.         5.824         5.721        -5.353
 ste   58657.         6.483         8.280        -6.481
Starlette SGF - ITT 
 str   58654.         2.019        -3.797        -3.906
 str   58655.         1.819        -5.068        -3.798
 str   58656.         2.427        -6.632        -4.657
 str   58657.         2.066        -7.247        -4.297