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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   60826.         2.172        -0.175        -2.342
 aji   60827.         2.249         0.585        -1.783
 aji   60828.         2.213         2.144        -1.899
 aji   60829.         2.196         3.756        -1.335
Ajisai SGF - DGF    
 aji   60826.        -0.423         5.344        -0.508
 aji   60827.         0.116        10.909        -1.894
 aji   60828.        -0.626        18.094        -0.707
 aji   60829.        -2.457        25.172        -1.507
 aji   60830.         1.894        37.017        -4.824
Ajisai ITT - DGF    
 aji   60826.        -2.594         5.519         1.834
 aji   60827.        -2.133        10.325        -0.111
 aji   60828.        -2.839        15.949         1.193
 aji   60829.        -3.850        21.648        -0.215
Beacon-C SGF - ITT  
 bec   60826.         0.973        23.128         1.738
 bec   60827.        -0.057        45.576         4.030
 bec   60828.        -6.750        80.744        10.786
 bec   60829.         1.835       119.123         6.152
Etalon-1 SGF - ITT  
 eta   60826.     -2672.315     -4582.314      2042.689
 eta   60827.       -49.265     -6621.099      4800.703
 eta   60828.      3356.993     -6113.829      4745.332
 eta   60829.      2315.390     -5383.440      1209.672
Etalon-1 SGF - DGF  
 eta   60826.         0.148         0.504        -0.225
 eta   60827.        -0.068         0.626        -0.490
 eta   60828.        -0.331         0.524        -0.479
 eta   60829.        -0.247         0.504        -0.169
 eta   60830.        -0.251         0.470        -0.092
Etalon-1 ITT - DGF  
 eta   60826.      2672.463      4582.818     -2042.914
 eta   60827.        49.197      6621.726     -4801.193
 eta   60828.     -3357.324      6114.356     -4745.808
 eta   60829.     -2315.595      5383.964     -1209.738
Etalon-2 SGF - ITT  
 etb   60826.        15.444       -20.132       -52.274
 etb   60827.        19.548       -10.834       -49.167
 etb   60828.        12.634        -4.030       -46.241
 etb   60829.         2.019        -8.346       -44.373
Etalon-2 SGF - DGF  
 etb   60826.        -0.162        -0.090         0.014
 etb   60827.        -0.137        -0.229        -0.050
 etb   60828.        -0.053        -0.387        -0.087
 etb   60829.         0.165        -0.504        -0.360
 etb   60830.         0.238        -0.439        -0.080
Etalon-2 ITT - DGF  
 etb   60826.       -15.606        20.041        52.289
 etb   60827.       -19.685        10.605        49.117
 etb   60828.       -12.687         3.643        46.154
 etb   60829.        -1.912         7.859        44.245
Larets SGF - ITT    
 lar   60826.        19.009       -26.716       -21.688
 lar   60827.        29.163       -37.523       -33.281
 lar   60828.        24.092       -76.106       -28.458
 lar   60829.        49.319       -89.778       -54.055
Larets SGF - DGF    
 lar   60826.        -5.713        18.582         3.058
 lar   60827.       -12.353        34.194         8.408
 lar   60828.        -7.166        67.084         3.459
 lar   60829.       -11.381       102.054         7.395
 lar   60830.       -26.234       122.497        20.284
Larets ITT - DGF    
 lar   60826.       -24.721        45.299        24.746
 lar   60827.       -41.516        71.717        41.689
 lar   60828.       -31.258       143.190        31.917
 lar   60829.       -75.040       177.200        72.971
LARES SGF - ITT     
 las   60826.         2.414         3.191         2.116
 las   60827.         1.648         5.372         3.596
 las   60828.         2.498         8.905         4.964
 las   60829.         0.741        11.747         6.599
LARES SGF - DGF     
 las   60826.         0.030         0.448         0.052
 las   60827.        -0.063         0.846         0.155
 las   60828.         0.018         1.388         0.197
 las   60829.        -0.242         2.045         0.250
 las   60830.         0.124         3.019         0.261
LARES ITT - DGF     
 las   60826.        -2.384        -2.743        -2.064
 las   60827.        -1.712        -4.526        -3.441
 las   60828.        -2.480        -7.517        -4.768
 las   60829.        -0.983        -9.702        -6.349
LARES-2 SGF - DGF   
 la2   60826.        -0.002         0.106        -0.018
 la2   60827.        -0.010         0.152        -0.003
 la2   60828.         0.019         0.200        -0.002
 la2   60829.        -0.003         0.260        -0.002
 la2   60830.        -0.024         0.302         0.025
LAGEOS-1 SGF - ITT  
 lga   60826.         4.569        -0.478        -0.108
 lga   60827.         4.473         1.140         0.386
 lga   60828.         4.785         0.975         0.790
 lga   60829.         4.619         2.618         0.836
LAGEOS-1 SGF - DGF  
 lga   60826.        -0.008        -0.123        -0.067
 lga   60827.         0.007        -0.184        -0.108
 lga   60828.         0.018        -0.159        -0.138
 lga   60829.         0.009        -0.317        -0.193
 lga   60830.         0.030        -0.302        -0.220
LAGEOS-2 SGF - ITT  
 lgb   60826.         4.035         2.977        -3.425
 lgb   60827.         2.515         4.416        -2.734
 lgb   60828.         4.780         7.013        -3.038
 lgb   60829.         2.035         8.461        -2.634
LAGEOS-2 SGF - DGF  
 lgb   60826.         0.000         0.025         0.016
 lgb   60827.         0.031         0.003         0.020
 lgb   60828.        -0.003        -0.169         0.011
 lgb   60829.         0.092        -0.273         0.082
 lgb   60830.         0.048        -0.621        -0.062
Stella SGF - ITT    
 ste   60826.         3.352         0.249        -0.999
 ste   60827.         3.331         0.799        -0.623
 ste   60828.         3.295         0.693        -0.125
 ste   60829.         3.099         0.842         0.340
Stella SGF - DGF    
 ste   60826.         0.428         2.538        -0.144
 ste   60827.         0.995         4.501        -0.917
 ste   60828.         2.178         7.816        -1.765
 ste   60829.         1.317        13.495        -1.214
 ste   60830.         0.902        18.468        -1.072
Stella ITT - DGF    
 ste   60826.        -2.924         2.290         0.855
 ste   60827.        -2.336         3.702        -0.294
 ste   60828.        -1.117         7.123        -1.641
 ste   60829.        -1.782        12.654        -1.554
Starlette SGF - ITT 
 str   60826.         1.590         4.750        -3.497
 str   60827.         1.831         7.371        -3.403
 str   60828.         1.569         9.904        -3.318
 str   60829.         0.902        12.604        -3.252
Starlette SGF - DGF 
 str   60826.        -0.152         0.332         0.038
 str   60827.        -0.132         0.417         0.064
 str   60828.        -0.105         0.288         0.054
 str   60829.        -0.169         0.094         0.086
 str   60830.        -0.168        -0.294         0.140
Starlette ITT - DGF 
 str   60826.        -1.741        -4.418         3.535
 str   60827.        -1.963        -6.954         3.467
 str   60828.        -1.674        -9.616         3.372
 str   60829.        -1.071       -12.510         3.338