Home » Quality Checks » CPF Comparison

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   59274.         1.284        -0.305        -0.968
 aji   59275.         1.482        -1.405        -1.403
 aji   59276.         1.211        -2.022        -0.799
 aji   59277.         1.360        -3.905        -1.003
Ajisai ITT - JAX    
Ajisai JAX - SGF    
Beacon-C SGF - ITT  
 bec   59274.        -0.138        -2.896        -1.525
 bec   59275.        -1.610        -8.647        -1.222
 bec   59276.        -1.865       -20.328        -1.437
 bec   59277.        -1.451       -37.884        -2.966
Cyrosat-2 ESA - ITT 
Etalon-1 SGF - ITT  
 eta   59274.         4.639         2.281        -2.185
 eta   59275.         3.920         2.228        -0.450
 eta   59276.         3.077         2.489         0.229
Etalon-1 SGF - DGF  
 eta   59274.         0.019         0.533        -0.322
 eta   59275.        -0.040         0.388        -0.554
 eta   59276.         0.034         0.444        -0.805
Etalon-1 ITT - DGF  
 eta   59274.        -4.620        -1.748         1.863
 eta   59275.        -3.960        -1.840        -0.105
 eta   59276.        -3.068        -1.774        -1.302
 eta   59277.        -3.262        -2.277        -1.424
Etalon-2 SGF - ITT  
 etb   59274.         4.836         0.634        -2.051
 etb   59275.         5.238         1.338        -2.367
 etb   59276.         5.020         2.484        -2.506
Etalon-2 SGF - DGF  
 etb   59274.         0.066        -0.019         0.032
 etb   59275.         0.153         0.003        -0.001
 etb   59276.         0.145         0.062         0.034
Etalon-2 ITT - DGF  
 etb   59274.        -4.770        -0.653         2.083
 etb   59275.        -5.085        -1.335         2.367
 etb   59276.        -4.875        -2.423         2.540
 etb   59277.        -4.102        -3.200         2.324
Larets SGF - ITT    
 lar   59274.         1.516        -2.765        -1.781
 lar   59275.         2.192        -3.703        -2.506
 lar   59276.         1.369        -4.561        -2.164
 lar   59277.         2.575        -5.007        -3.223
LARES SGF - ITT     
 las   59274.         0.951        -1.297        -0.050
 las   59275.         1.279        -2.417        -0.144
 las   59276.         0.676        -3.543         0.241
 las   59277.         1.322        -5.643        -0.250
LAGEOS-1 SGF - ITT  
 lga   59274.         2.430         0.249        -0.584
 lga   59275.         2.959         0.180        -1.059
 lga   59276.         2.855         0.597        -0.988
 lga   59277.         2.606         0.243        -0.590
LAGEOS-1 ITT - JAX  
LAGEOS-1 JAX - SGF  
LAGEOS-1 SGF - DGF  
 lga   59274.         0.005        -0.054         0.034
 lga   59275.        -0.012        -0.070         0.053
 lga   59276.        -0.020        -0.104         0.062
 lga   59277.         0.009        -0.114         0.070
LAGEOS-2 SGF - ITT  
 lgb   59274.         1.615         0.742        -1.105
 lgb   59275.         1.952         0.824        -1.433
 lgb   59276.         1.506         0.121        -1.415
 lgb   59277.         2.068         0.351        -1.525
LAGEOS-2 ITT - JAX  
LAGEOS-2 JAX - SGF  
LAGEOS-2 SGF - DGF  
 lgb   59274.        -0.001        -0.011         0.095
 lgb   59275.         0.096        -0.108        -0.002
 lgb   59276.        -0.024        -0.550         0.070
 lgb   59277.         0.179        -0.636        -0.016
Stella SGF - ITT    
 ste   59274.         1.672        -0.291        -1.506
 ste   59275.         1.367        -1.234        -1.385
 ste   59276.         1.127        -3.409        -1.278
 ste   59277.         1.604        -5.013        -1.843
Starlette SGF - ITT 
 str   59274.         1.214        -1.038        -2.279
 str   59275.         1.183        -3.291        -2.457
 str   59276.         2.022        -5.863        -3.452
 str   59277.         0.440       -10.010        -1.828