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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   58287.         2.925        -7.145        -3.743
 aji   58288.         3.997       -12.846        -4.353
 aji   58289.         2.237       -20.090        -3.511
 aji   58290.         4.596       -28.175        -3.547
Ajisai ITT - JAX    
 aji   58287.        -2.778         4.212         3.826
 aji   58288.        -3.508         7.710         4.243
 aji   58289.        -3.356        11.831         4.294
Ajisai JAX - SGF    
 aji   58287.        -0.146         2.933        -0.084
 aji   58288.        -0.490         5.136         0.110
 aji   58289.        -0.416         8.039         0.221
Beacon-C SGF - ITT  
 bec   58287.         2.534        13.797        -4.138
 bec   58288.         3.984        41.858        -4.856
 bec   58289.        -6.936        88.940        -0.523
 bec   58290.        -5.492       165.608        -1.699
Cyrosat-2 ESA - ITT 
 cyb   58287.         6.384        -8.440        -8.648
 cyb   58288.         4.302       -12.489        -9.076
 cyb   58289.        13.126       -19.277       -17.498
 cyb   58290.        16.547       -24.332       -24.769
Etalon-1 SGF - ITT  
 eta   58287.        10.720        -5.267       -10.416
 eta   58288.         9.273        -4.532        -6.064
 eta   58289.        11.892        -3.547       -11.171
 eta   58290.        12.865        -1.927       -14.408
Etalon-2 SGF - ITT  
 etb   58287.        10.148        -1.381         1.786
 etb   58288.         8.723        -1.227         3.413
 etb   58289.         8.914        -2.356         5.076
 etb   58290.        10.429        -2.371         5.528
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
 jsb   58287.        -0.406        -4.308         0.627
 jsb   58288.        -2.050       -10.833         2.306
 jsb   58289.       -14.768      -100.383        15.606
 jsb   58290.       -19.584      -195.521        18.840
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   58287.         1.980         3.596        -1.099
 lar   58288.        -2.042        12.752         2.391
 lar   58289.         0.339        30.643        -0.438
 lar   58290.       -13.471        51.900        11.669
LARES SGF - ITT     
 las   58287.         2.950         0.295         0.428
 las   58288.         2.130         0.815         1.684
 las   58289.         2.539         2.154         2.162
 las   58290.         1.650         2.391         3.360
LAGEOS-1 SGF - ITT  
 lga   58287.         5.213        -3.663        -1.187
 lga   58288.         5.463        -5.563        -1.998
 lga   58289.         7.077        -6.738        -1.702
 lga   58290.         6.272        -7.774         0.039
LAGEOS-1 ITT - JAX  
 lga   58287.        -5.239         3.593         1.319
 lga   58288.        -5.489         5.417         2.069
 lga   58289.        -7.141         6.597         2.782
LAGEOS-1 JAX - SGF  
 lga   58287.         0.026         0.069        -0.132
 lga   58288.         0.026         0.146        -0.072
 lga   58289.        -0.039         0.213        -0.056
LAGEOS-2 SGF - ITT  
 lgb   58287.         4.251         1.859        -3.054
 lgb   58288.         5.758         5.536        -4.386
 lgb   58289.         3.012         7.639        -2.395
 lgb   58290.         7.962        13.929        -5.622
LAGEOS-2 ITT - JAX  
 lgb   58287.        -4.254        -2.013         3.109
 lgb   58288.        -5.833        -5.842         4.481
 lgb   58289.        -2.951        -8.038         2.415
LAGEOS-2 JAX - SGF  
 lgb   58287.         0.003         0.155        -0.056
 lgb   58288.         0.075         0.306        -0.095
 lgb   58289.        -0.061         0.399        -0.020
Stella SGF - ITT    
 ste   58287.         4.872         1.536        -2.390
 ste   58288.         4.867         3.939        -1.879
 ste   58289.         5.284         7.138        -1.849
 ste   58290.         5.577        11.199        -1.782
Starlette SGF - ITT 
 str   58287.         2.600        -6.923        -3.246
 str   58288.         1.922       -10.720        -2.512
 str   58289.         2.393       -15.798        -3.232
 str   58290.         2.198       -21.713        -3.363