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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   58228.         1.443         4.992        -1.845
 aji   58229.         1.425         9.172        -1.956
 aji   58230.         1.910        13.433        -2.214
 aji   58231.         1.390        18.958        -2.073
Ajisai ITT - JAX    
 aji   58228.        -1.488        -5.108         2.022
 aji   58229.        -1.506        -9.230         2.176
 aji   58230.        -1.984       -13.440         2.452
Ajisai JAX - SGF    
 aji   58228.         0.045         0.116        -0.177
 aji   58229.         0.081         0.058        -0.220
 aji   58230.         0.074         0.007        -0.237
Beacon-C SGF - ITT  
 bec   58228.        -3.060        24.292        -2.480
 bec   58229.        -7.415        61.871        -2.199
 bec   58230.        -3.728       120.108        -9.772
 bec   58231.        -5.444       198.637       -10.784
Cyrosat-2 ESA - ITT 
 cyb   58228.        10.064       -13.309        -6.259
 cyb   58229.        22.430       -22.417       -15.723
 cyb   58230.        30.861       -34.116       -21.049
Etalon-1 SGF - ITT  
 eta   58228.         4.004        -0.732         2.063
 eta   58229.         4.348        -0.464         3.086
 eta   58230.         5.359         0.139         3.659
 eta   58231.         6.048         1.635         3.988
Etalon-2 SGF - ITT  
 etb   58228.         3.719        -1.037        -0.063
 etb   58229.         5.130        -2.036        -0.701
 etb   58230.         5.993        -1.304        -1.002
 etb   58231.         6.369         0.420        -1.254
Jason-2 SGF - ITT   
Jason-2 ITT - CNES  
Jason-2 CNES - SGF  
Larets SGF - ITT    
 lar   58228.         2.199        -3.789        -0.362
 lar   58229.         2.942        -5.039        -0.340
 lar   58230.         3.244        -7.457        -0.640
 lar   58231.         4.608        -9.580        -0.874
LARES SGF - ITT     
 las   58228.         2.138         5.342        -0.039
 las   58229.         1.809        10.506         0.356
 las   58230.         2.645        15.216         0.000
 las   58231.         1.880        23.108        -0.139
LAGEOS-1 SGF - ITT  
 lga   58228.         2.282        -4.037         3.068
 lga   58229.         3.631        -4.613         4.134
 lga   58230.         2.466        -7.076         8.623
 lga   58231.         2.884        -9.272         6.157
LAGEOS-1 ITT - JAX  
 lga   58228.        -2.327         3.857        -3.052
 lga   58229.        -3.583         4.382        -4.151
 lga   58230.        -3.695         5.919        -8.000
LAGEOS-1 JAX - SGF  
 lga   58228.         0.045         0.180        -0.016
 lga   58229.        -0.048         0.231         0.017
 lga   58230.        -0.070         0.320        -0.085
LAGEOS-2 SGF - ITT  
 lgb   58228.         3.047         3.154        -1.608
 lgb   58229.         1.164         6.414        -0.927
 lgb   58230.         4.078         7.852        -1.657
 lgb   58231.         1.273        12.899        -0.972
LAGEOS-2 ITT - JAX  
 lgb   58228.        -3.003        -3.108         1.569
 lgb   58229.        -1.118        -6.254         0.901
 lgb   58230.        -3.251        -7.603         1.112
LAGEOS-2 JAX - SGF  
 lgb   58228.        -0.044        -0.047         0.040
 lgb   58229.        -0.046        -0.160         0.026
 lgb   58230.        -0.077        -0.241         0.047
Stella SGF - ITT    
 ste   58228.         0.773        -2.600         1.035
 ste   58229.         0.869        -3.841         1.523
 ste   58230.         1.217        -4.289         1.546
 ste   58231.         0.379        -6.551         2.655
Starlette SGF - ITT 
 str   58228.         1.004        -1.147        -0.943
 str   58229.         0.891        -3.085        -0.722
 str   58230.         0.582        -6.529        -0.309
 str   58231.         0.892       -11.633        -0.444