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   58044.         5.146         6.461        -4.384
 aji   58045.         5.078        10.543        -4.234
 aji   58046.         5.350        15.637        -4.111
 aji   58047.         5.335        21.186        -3.969
Ajisai ITT - JAX    
 aji   58044.        -5.039        -5.879         4.335
 aji   58045.        -4.988        -9.314         4.215
 aji   58046.        -5.253       -13.747         4.062
Ajisai JAX - SGF    
 aji   58044.        -0.107        -0.582         0.049
 aji   58045.        -0.090        -1.229         0.018
 aji   58046.        -0.097        -1.890         0.049
Beacon-C SGF - ITT  
 bec   58044.         0.450        -3.068        -6.688
 bec   58045.         0.406        -6.578        -8.571
 bec   58046.         0.311        -8.136        -9.767
 bec   58047.        -0.101        -7.683       -10.545
Cyrosat-2 ESA - ITT 
 cyb   58044.       -29.588       -10.179        37.792
 cyb   58045.       -15.147       -11.777        17.508
 cyb   58046.      -142.940      -115.540       116.722
Etalon-1 SGF - ITT  
 eta   58044.        19.707        13.526         6.016
 eta   58045.        16.916        19.722         0.900
 eta   58046.         9.222        24.213         0.347
 eta   58047.        14.888        24.276        16.089
Etalon-2 SGF - ITT  
 etb   58044.        12.634         5.782         1.179
 etb   58045.        16.266        10.258         0.640
 etb   58046.        17.428        14.805         0.527
 etb   58047.        17.620        18.080         0.365
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
 jsb   58044.         1.990        75.307       -11.944
 jsb   58045.         2.834       136.597       -14.576
 jsb   58046.       -39.434       242.721         8.544
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   58044.         5.535         0.739        -1.613
 lar   58045.         5.905        -2.844        -2.296
 lar   58046.         8.570       -11.325        -3.720
 lar   58047.        10.824       -27.359        -8.152
LARES SGF - ITT     
 las   58044.         5.841         0.049        -4.363
 las   58045.         6.152        -3.000        -7.517
 las   58046.         6.524        -5.986       -12.165
 las   58047.         6.843        -8.863       -15.631
LAGEOS-1 SGF - ITT  
 lga   58044.         9.989         1.604         0.276
 lga   58045.         7.694         1.215        -0.835
 lga   58046.         8.571        -0.263         1.579
 lga   58047.        10.238        -2.581         2.882
LAGEOS-1 ITT - JAX  
 lga   58044.        -9.958        -1.634        -0.302
 lga   58045.        -7.707        -1.251         0.786
 lga   58046.        -7.233        -0.337        -0.789
LAGEOS-1 JAX - SGF  
 lga   58044.        -0.031         0.031         0.027
 lga   58045.         0.013         0.036         0.049
 lga   58046.         0.026         0.070         0.018
LAGEOS-2 SGF - ITT  
 lgb   58044.         7.715         8.962        -4.530
 lgb   58045.         7.040        15.153        -5.518
 lgb   58046.         7.827        18.386        -5.176
 lgb   58047.         8.247        28.913        -6.586
LAGEOS-2 ITT - JAX  
 lgb   58044.        -7.800        -9.744         4.600
 lgb   58045.        -7.073       -16.453         5.567
 lgb   58046.        -7.917       -19.818         5.259
LAGEOS-2 JAX - SGF  
 lgb   58044.         0.085         0.781        -0.071
 lgb   58045.         0.033         1.299        -0.049
 lgb   58046.         0.090         1.432        -0.083
Stella SGF - ITT    
 ste   58044.         5.054         2.858        -0.822
 ste   58045.         5.097         3.422        -0.915
 ste   58046.         4.954         3.983        -0.512
 ste   58047.         4.423         3.805        -0.106
Starlette SGF - ITT 
 str   58044.         3.916        -1.915        -2.401
 str   58045.         4.520        -6.888        -3.262
 str   58046.         4.285       -14.768        -2.789
 str   58047.         4.822       -25.212        -4.685