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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   59177.         3.260         2.609        -4.253
 aji   59178.         3.333         3.043        -4.052
 aji   59179.         3.343         3.514        -3.693
 aji   59180.         3.396         4.050        -3.913
Ajisai ITT - JAX    
 aji   59177.        -3.295        -1.538         4.025
 aji   59178.        -3.503        -1.465         3.894
 aji   59179.        -3.218        -0.969         3.201
Ajisai JAX - SGF    
 aji   59177.         0.035        -1.070         0.228
 aji   59178.         0.170        -1.579         0.158
 aji   59179.        -0.125        -2.545         0.492
Beacon-C SGF - ITT  
 bec   59177.         2.087        -2.837        -3.761
 bec   59178.         2.869        -4.467        -4.151
 bec   59179.         2.899        -5.821        -4.191
 bec   59180.         3.129        -6.152        -4.180
Cyrosat-2 ESA - ITT 
Etalon-1 SGF - ITT  
 eta   59177.         9.005         6.068        -1.662
 eta   59178.         8.885         4.639        -3.709
 eta   59179.         8.762         4.801        -4.053
Etalon-1 SGF - DGF  
 eta   59177.         0.168         0.406         0.153
 eta   59178.         0.040         0.555         0.200
 eta   59179.         0.024         0.559         0.243
Etalon-1 ITT - DGF  
 eta   59177.        -8.837        -5.662         1.815
 eta   59178.        -8.845        -4.084         3.908
 eta   59179.        -8.738        -4.242         4.295
 eta   59180.        -8.204        -4.215         5.065
Etalon-2 SGF - ITT  
 etb   59177.         9.692        10.816       -17.975
 etb   59178.        12.432        12.865       -12.565
 etb   59179.        11.414        16.016       -20.474
Etalon-2 SGF - DGF  
 etb   59177.        -0.028         0.148        -0.157
 etb   59178.         0.057         0.154        -0.119
 etb   59179.         0.032         0.176        -0.231
Etalon-2 ITT - DGF  
 etb   59177.        -9.720       -10.668        17.818
 etb   59178.       -12.375       -12.711        12.446
 etb   59179.        -9.753       -20.250        16.736
 etb   59180.       -15.288       -12.918        28.668
Larets SGF - ITT    
 lar   59177.         2.764         3.540         1.604
 lar   59178.         3.139         5.166         1.966
 lar   59179.         2.353         6.009         2.727
 lar   59180.         3.673         7.927         2.709
LARES SGF - ITT     
 las   59177.         3.452         5.767        -2.008
 las   59178.         3.500         8.498        -1.877
 las   59179.         2.883        12.271        -1.377
 las   59180.         3.345        15.472        -1.351
LAGEOS-1 SGF - ITT  
 lga   59177.         4.952         2.680         1.330
 lga   59178.         5.188         2.434         2.366
 lga   59179.         5.449         2.108         1.933
 lga   59180.         4.476         1.922         3.773
LAGEOS-1 ITT - JAX  
 lga   59177.        -4.955        -2.624        -1.306
 lga   59178.        -5.211        -2.403        -2.332
 lga   59179.        -5.502        -2.083        -2.013
LAGEOS-1 JAX - SGF  
 lga   59177.         0.003        -0.055        -0.024
 lga   59178.         0.023        -0.031        -0.034
 lga   59179.        -0.002        -0.025        -0.015
LAGEOS-1 SGF - DGF  
 lga   59177.         0.000         0.025        -0.015
 lga   59178.        -0.016         0.052        -0.077
 lga   59179.        -0.038         0.077        -0.035
 lga   59180.         0.019         0.067        -0.138
LAGEOS-2 SGF - ITT  
 lgb   59177.         4.940         3.777        -5.112
 lgb   59178.         5.712         6.071        -4.751
 lgb   59179.         3.706         8.387        -3.690
 lgb   59180.         7.309        12.730        -4.639
LAGEOS-2 ITT - JAX  
 lgb   59177.        -4.935        -4.488         5.013
 lgb   59178.        -5.960        -7.152         4.767
 lgb   59179.        -3.525        -9.628         3.395
LAGEOS-2 JAX - SGF  
 lgb   59177.        -0.005         0.712         0.099
 lgb   59178.         0.249         1.081        -0.016
 lgb   59179.        -0.181         1.242         0.295
LAGEOS-2 SGF - DGF  
 lgb   59177.        -0.028         0.238        -0.019
 lgb   59178.        -0.016         0.156         0.031
 lgb   59179.        -0.017         0.056        -0.050
 lgb   59180.        -0.103        -0.185         0.127
Stella SGF - ITT    
 ste   59177.         4.602         5.994        -0.893
 ste   59178.         4.575         8.991        -0.646
 ste   59179.         4.507        12.464        -0.175
 ste   59180.         4.564        15.251         0.089
Starlette SGF - ITT 
 str   59177.         3.200         4.181        -4.176
 str   59178.         3.171         6.890        -3.924
 str   59179.         2.869         9.098        -3.873
 str   59180.         3.113        13.849        -3.814