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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   59110.         3.530        -3.961        -4.678
 aji   59111.         3.364        -6.643        -4.482
 aji   59112.         3.372       -10.462        -4.515
 aji   59113.         2.943       -16.101        -4.370
Ajisai ITT - JAX    
 aji   59110.        -3.559         3.388         4.760
 aji   59111.        -3.435         5.497         4.620
 aji   59112.        -3.464         8.629         4.684
Ajisai JAX - SGF    
 aji   59110.         0.030         0.573        -0.083
 aji   59111.         0.071         1.146        -0.138
 aji   59112.         0.093         1.832        -0.169
Beacon-C SGF - ITT  
 bec   59110.         2.900         8.136        -5.522
 bec   59111.         2.713        29.514        -5.893
 bec   59112.         4.048        69.896        -0.446
 bec   59113.        -1.663       138.206        13.918
Cyrosat-2 ESA - ITT 
Etalon-1 SGF - ITT  
 eta   59110.        11.638        11.806        -6.252
 eta   59111.        12.005        13.243        -0.392
 eta   59112.        11.162        15.102         1.494
 eta   59113.         9.566        16.958         2.887
Etalon-1 SGF - DGF  
 eta   59110.         0.049         0.245        -0.074
 eta   59111.         0.036         0.188         0.141
 eta   59112.         0.082         0.213         0.348
 eta   59113.         0.085         0.285         0.542
Etalon-1 ITT - DGF  
 eta   59110.       -11.589       -11.561         6.178
 eta   59111.       -11.969       -13.055         0.534
 eta   59112.       -11.080       -14.889        -1.146
 eta   59113.        -9.481       -16.673        -2.345
Etalon-2 SGF - ITT  
 etb   59110.        11.986         2.696        -1.830
 etb   59111.        12.443         2.233         0.724
 etb   59112.        13.142         0.837         2.334
 etb   59113.        16.244        12.169        -0.640
Etalon-2 SGF - DGF  
 etb   59110.        -0.008         0.126         0.030
 etb   59111.        -0.033         0.066        -0.067
 etb   59112.        -0.013         0.005        -0.168
 etb   59113.         0.037         0.100        -0.291
Etalon-2 ITT - DGF  
 etb   59110.       -11.994        -2.570         1.860
 etb   59111.       -12.476        -2.167        -0.791
 etb   59112.       -13.155        -0.832        -2.501
 etb   59113.       -16.219       -11.986         0.338
Larets SGF - ITT    
 lar   59110.         6.341        -3.051        -4.951
 lar   59111.         5.944        -3.640        -5.789
 lar   59112.         6.327        -3.863        -6.821
 lar   59113.         6.973        -3.522        -8.151
LARES SGF - ITT     
 las   59110.         6.546        -3.806        -4.770
 las   59111.         7.213        -9.102        -6.487
 las   59112.         7.499       -14.271        -7.866
 las   59113.         8.276       -21.799       -11.298
LAGEOS-1 SGF - ITT  
 lga   59110.         8.244         1.409         0.077
 lga   59111.         8.679         1.066         0.069
 lga   59112.         7.823         1.440        -1.630
 lga   59113.         7.486         0.984         0.238
LAGEOS-1 ITT - JAX  
 lga   59110.        -8.272        -1.392        -0.052
 lga   59111.        -8.658        -1.090        -0.043
 lga   59112.        -7.834        -1.494         1.603
LAGEOS-1 JAX - SGF  
 lga   59110.         0.028        -0.017        -0.024
 lga   59111.        -0.021         0.024        -0.027
 lga   59112.         0.011         0.053         0.027
LAGEOS-1 SGF - DGF  
 lga   59110.         0.015        -0.036        -0.060
 lga   59111.        -0.028        -0.022        -0.079
 lga   59112.         0.008        -0.040        -0.048
 lga   59113.         0.032        -0.001        -0.154
 lga   59114.        -0.049        -0.025        -0.151
LAGEOS-2 SGF - ITT  
 lgb   59110.         5.609        -1.941        -4.573
 lgb   59111.         6.678        -5.164        -5.693
 lgb   59112.         4.751        -5.393        -3.827
 lgb   59113.         6.855       -12.567        -6.911
LAGEOS-2 ITT - JAX  
 lgb   59110.        -5.541         2.400         4.570
 lgb   59111.        -6.682         5.900         5.774
 lgb   59112.        -4.583         6.164         3.779
LAGEOS-2 JAX - SGF  
 lgb   59110.        -0.068        -0.459         0.003
 lgb   59111.         0.003        -0.736        -0.081
 lgb   59112.        -0.168        -0.771         0.049
LAGEOS-2 SGF - DGF  
 lgb   59110.         0.017        -0.039         0.028
 lgb   59111.         0.018         0.076         0.018
 lgb   59112.         0.055         0.163         0.016
 lgb   59113.         0.009         0.366         0.033
 lgb   59114.         0.092         0.406         0.016
Stella SGF - ITT    
 ste   59110.         6.869         3.415        -4.315
 ste   59111.         7.574         7.060        -5.720
 ste   59112.         7.600        12.088        -6.023
 ste   59113.         7.836        15.608        -6.673
Starlette SGF - ITT 
 str   59110.         2.979        -0.703        -3.827
 str   59111.         2.809        -1.388        -3.682
 str   59112.         2.707        -1.579        -3.667
 str   59113.         2.716        -2.124        -3.649