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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   57987.         4.323        -0.605        -5.426
 aji   57988.         4.532        -1.642        -6.249
 aji   57989.         4.118        -2.870        -6.383
 aji   57990.         3.917        -4.208        -6.388
Ajisai ITT - JAX    
 aji   57987.        -4.428        -0.061         5.337
 aji   57988.        -4.555         1.068         6.070
 aji   57989.        -4.151         2.339         6.133
Ajisai JAX - SGF    
 aji   57987.         0.105         0.665         0.089
 aji   57988.         0.022         0.574         0.179
 aji   57989.         0.033         0.531         0.250
Beacon-C SGF - ITT  
 bec   57987.         7.247        35.457        -8.188
 bec   57988.         9.464        94.930        -7.015
 bec   57989.         9.029       198.305        -2.771
 bec   57990.         2.401       359.147         9.220
Cyrosat-2 ESA - ITT 
 cyb   57987.         8.448        -0.724         1.331
 cyb   57988.        11.324         2.156         2.024
 cyb   57989.        16.775        13.147         2.170
 cyb   57990.        24.533        20.502         1.563
Etalon-1 SGF - ITT  
 eta   57987.        16.989         6.258        -2.007
 eta   57988.        15.866         8.624        -1.521
 eta   57989.        14.585         8.002        -0.507
 eta   57990.        10.635        11.427         0.444
Etalon-2 SGF - ITT  
 etb   57987.        15.369         6.247        -4.172
 etb   57988.        14.851         9.276        -3.257
 etb   57989.        12.877        10.867        -0.709
 etb   57990.        15.003        16.575        -1.981
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   57987.         6.176        -5.574        -1.349
 lar   57988.         6.340        -6.347        -1.117
 lar   57989.         6.121        -7.397        -0.397
 lar   57990.         4.444        -5.427         1.160
LARES SGF - ITT     
 las   57987.         2.584        -8.211        -3.845
 las   57988.         0.718       -24.067        -4.660
 las   57989.        -1.869       -43.852        -5.539
 las   57990.        -6.563       -84.260        -4.956
LAGEOS-1 SGF - ITT  
 lga   57987.         7.648         1.011        -2.731
 lga   57988.        10.311         4.677        -2.990
 lga   57989.        13.604        10.955        -8.059
 lga   57990.         7.122        13.866        -8.681
LAGEOS-1 ITT - JAX  
 lga   57987.        -7.818        -0.867         2.861
 lga   57988.       -10.547        -4.356         3.110
 lga   57989.       -14.760       -10.996         8.078
LAGEOS-1 JAX - SGF  
 lga   57987.         0.170        -0.144        -0.130
 lga   57988.         0.237        -0.320        -0.120
 lga   57989.         0.252        -0.302        -0.247
LAGEOS-2 SGF - ITT  
 lgb   57987.         7.776        -6.837        -7.594
 lgb   57988.         6.147       -13.620        -6.102
 lgb   57989.        10.042       -20.574        -9.161
 lgb   57990.         4.305       -27.385        -8.698
LAGEOS-2 ITT - JAX  
 lgb   57987.        -7.946         7.183         7.660
 lgb   57988.        -6.282        14.276         6.193
 lgb   57989.       -10.225        21.329         9.187
LAGEOS-2 JAX - SGF  
 lgb   57987.         0.169        -0.346        -0.065
 lgb   57988.         0.135        -0.655        -0.090
 lgb   57989.         0.183        -0.755        -0.026
Stella SGF - ITT    
 ste   57987.         3.331        -3.889        -3.589
 ste   57988.        -0.034       -16.565        -1.762
 ste   57989.         3.648       -28.293        -7.544
 ste   57990.       -11.231       -63.140         6.183
Starlette SGF - ITT 
 str   57987.         5.078        -9.035        -4.184
 str   57988.         5.465       -17.171        -4.724
 str   57989.         8.322       -27.685        -7.297
 str   57990.         5.814       -40.608        -3.982