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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   57898.         1.625         0.566        -1.663
 aji   57899.         1.642         1.801        -1.862
 aji   57900.         1.620         2.896        -1.600
 aji   57901.         1.755         4.538        -1.772
Ajisai ITT - JAX    
 aji   57898.        -1.627        -0.437         1.734
 aji   57899.        -1.654        -1.499         1.932
 aji   57900.        -1.614        -2.283         1.591
Ajisai JAX - SGF    
 aji   57898.         0.002        -0.129        -0.071
 aji   57899.         0.012        -0.302        -0.069
 aji   57900.        -0.006        -0.613         0.009
Beacon-C SGF - ITT  
 bec   57898.         3.227        -7.910        -1.830
 bec   57899.         4.530       -22.827         0.266
 bec   57900.         9.482       -51.562         1.188
 bec   57901.         8.614       -95.675         4.782
Cyrosat-2 ESA - ITT 
 cyb   57898.         2.291        -4.315        -0.433
 cyb   57899.         3.914        -4.007        -0.115
 cyb   57900.         4.830        -2.355         1.463
 cyb   57901.         4.624         2.070         4.716
Etalon-1 SGF - ITT  
 eta   57898.         7.297        -4.408       -11.395
 eta   57899.         9.009        -6.463        -7.567
 eta   57900.         9.090        -6.190        -1.422
 eta   57901.         6.371         2.231       -12.723
Etalon-2 SGF - ITT  
 etb   57898.         9.124        -6.194        -5.328
 etb   57899.         7.109        -4.683        -7.340
 etb   57900.         2.738        -5.332        -6.955
 etb   57901.        11.924        -1.826        -7.794
Jason-2 SGF - ITT   
 jsb   57898.         3.982        -3.983        -3.519
 jsb   57899.         5.683       -13.426        -5.421
 jsb   57900.         7.900       -25.380        -9.686
 jsb   57901.        12.307       -52.397       -10.654
Jason-2 ITT - CNES  
 jsb   57898.        -8.620        16.568         6.774
 jsb   57899.       -11.533        38.855        10.257
 jsb   57900.       -14.174        63.199        17.404
 jsb   57901.       -23.103       115.468        17.078
Jason-2 CNES - SGF  
 jsb   57898.         4.638       -12.585        -3.255
 jsb   57899.         5.850       -25.429        -4.836
 jsb   57900.         6.274       -37.819        -7.719
 jsb   57901.        10.796       -63.071        -6.424
Larets SGF - ITT    
 lar   57898.         5.203        -7.969        -5.761
 lar   57899.         5.253       -14.646        -6.198
 lar   57900.         4.536       -25.183        -6.452
 lar   57901.        12.531       -36.264       -15.040
LARES SGF - ITT     
 las   57898.         4.411        -4.304        -5.416
 las   57899.         5.736        -9.794        -7.965
 las   57900.         8.143       -23.635       -11.505
 las   57901.        10.436       -36.849       -14.887
LAGEOS-1 SGF - ITT  
 lga   57898.         5.852         0.285        -3.115
 lga   57899.         4.031         0.224        -1.088
 lga   57900.         8.001         6.051        -3.911
 lga   57901.         9.636        15.568        -6.456
LAGEOS-1 ITT - JAX  
 lga   57898.        -5.846        -0.293         3.163
 lga   57899.        -4.043        -0.230         1.155
 lga   57900.        -8.008        -6.085         3.983
LAGEOS-1 JAX - SGF  
 lga   57898.        -0.006         0.008        -0.048
 lga   57899.         0.012         0.006        -0.066
 lga   57900.         0.007         0.034        -0.072
LAGEOS-2 SGF - ITT  
 lgb   57898.         2.684         1.260        -2.933
 lgb   57899.         2.858         1.668        -2.450
 lgb   57900.         2.530         2.685        -2.376
 lgb   57901.         3.607         3.958        -3.096
LAGEOS-2 ITT - JAX  
 lgb   57898.        -2.658        -1.880         2.920
 lgb   57899.        -2.678        -2.676         2.506
 lgb   57900.        -2.324        -3.829         2.283
LAGEOS-2 JAX - SGF  
 lgb   57898.        -0.026         0.620         0.013
 lgb   57899.        -0.180         1.008        -0.056
 lgb   57900.        -0.101         1.237        -0.055
Stella SGF - ITT    
 ste   57898.         3.104         0.001        -1.882
 ste   57899.         3.543         1.886        -1.949
 ste   57900.         4.899         5.496        -2.912
 ste   57901.         6.094        11.787        -3.855
Starlette SGF - ITT 
 str   57898.         1.092         3.276        -1.024
 str   57899.         0.746         7.047        -0.807
 str   57900.         0.836        12.530        -0.526
 str   57901.         0.402        19.021        -0.954