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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   58720.         5.298        -7.196        -6.039
 aji   58721.         4.853       -11.303        -4.716
 aji   58722.         6.135       -13.924        -5.609
 aji   58723.         5.353       -16.857        -5.486
Ajisai ITT - JAX    
 aji   58720.        -5.400         7.212         6.244
 aji   58721.        -4.966        11.542         4.880
 aji   58722.        -6.255        14.229         5.836
Ajisai JAX - SGF    
 aji   58720.         0.103        -0.015        -0.205
 aji   58721.         0.113        -0.240        -0.164
 aji   58722.         0.119        -0.305        -0.228
Beacon-C SGF - ITT  
 bec   58720.         5.963        24.358         3.705
 bec   58721.        10.920        52.648         7.615
 bec   58722.         7.245        95.567        15.829
 bec   58723.         4.857       148.620        26.590
Cyrosat-2 ESA - ITT 
Etalon-1 SGF - ITT  
 eta   58720.        16.185         0.837       -11.285
 eta   58721.        15.389         2.931       -15.872
 eta   58722.        11.610         4.615       -19.125
 eta   58723.        15.460         1.968       -17.277
Etalon-2 SGF - ITT  
 etb   58720.        13.292        -4.870        -6.291
 etb   58721.        13.119        -6.005        -6.484
 etb   58722.        12.744        -7.337        -7.450
 etb   58723.        13.111        -8.838        -7.899
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
 jsb   58720.        -8.101         3.278         2.167
 jsb   58721.        -9.404         7.039        -1.259
 jsb   58722.       -10.752        13.182        -6.384
 jsb   58723.       -12.248        21.873       -12.431
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   58720.         8.124        -5.792        -5.642
 lar   58721.         7.176        -8.193        -5.267
 lar   58722.         7.712        -9.761        -5.506
 lar   58723.         9.005       -10.825        -6.970
LARES SGF - ITT     
 las   58720.         8.149        -6.311        -6.771
 las   58721.         8.119        -7.912        -7.448
 las   58722.         9.472       -10.856        -7.654
 las   58723.         9.693       -12.914        -8.293
LAGEOS-1 SGF - ITT  
 lga   58720.         8.741        -1.850        -5.954
 lga   58721.         9.936        -1.103        -7.083
 lga   58722.         9.334        -1.855        -6.708
 lga   58723.        10.020        -3.120        -8.503
LAGEOS-1 ITT - JAX  
 lga   58720.        -8.734         1.794         5.841
 lga   58721.        -9.909         1.097         6.942
 lga   58722.        -9.626         1.205         7.343
LAGEOS-1 JAX - SGF  
 lga   58720.        -0.007         0.056         0.113
 lga   58721.        -0.027         0.006         0.140
 lga   58722.        -0.015         0.023         0.144
LAGEOS-2 SGF - ITT  
 lgb   58720.         9.109         8.190       -10.382
 lgb   58721.         8.043        13.203        -9.638
 lgb   58722.        11.122        21.812       -12.034
 lgb   58723.         6.589        30.839        -9.740
LAGEOS-2 ITT - JAX  
 lgb   58720.        -9.261        -9.543        10.501
 lgb   58721.        -8.013       -14.871         9.639
 lgb   58722.       -11.444       -24.200        12.278
LAGEOS-2 JAX - SGF  
 lgb   58720.         0.153         1.352        -0.119
 lgb   58721.        -0.030         1.667        -0.001
 lgb   58722.         0.321         2.388        -0.243
Stella SGF - ITT    
 ste   58720.         5.757        -0.105        -4.192
 ste   58721.         5.767        -0.709        -4.539
 ste   58722.         5.856        -1.343        -5.113
 ste   58723.         5.892        -1.823        -5.541
Starlette SGF - ITT 
 str   58720.         4.391        -3.351        -4.515
 str   58721.         4.179        -2.828        -3.840
 str   58722.         4.716        -1.992        -3.651
 str   58723.         4.385        -0.280        -3.131