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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   60817.         1.763         0.312        -1.999
 aji   60818.         1.869         1.821        -2.130
 aji   60819.         2.044         3.461        -2.107
 aji   60820.         1.721         5.345        -1.895
Ajisai SGF - DGF    
 aji   60817.         0.071         3.081        -0.555
 aji   60818.         0.418         7.239        -1.266
 aji   60819.         0.526        11.776        -1.760
 aji   60820.        -0.741        16.995        -1.507
 aji   60821.         1.313        26.162        -3.471
Ajisai ITT - DGF    
 aji   60817.        -1.692         2.769         1.445
 aji   60818.        -1.450         5.418         0.864
 aji   60819.        -1.518         8.315         0.347
 aji   60820.        -2.335        11.729         0.329
Beacon-C SGF - ITT  
 bec   60817.        -2.663       -67.586         1.908
 bec   60818.         5.359      -134.017        -2.678
 bec   60819.       -12.949      -226.894        15.290
 bec   60820.       -17.648      -335.126        15.258
Etalon-1 SGF - ITT  
 eta   60817.         9.992         4.828       -40.775
 eta   60818.         6.865        13.451       -53.081
 eta   60819.         0.775        23.666       -74.859
 eta   60820.        -0.296         3.033       -84.839
Etalon-1 SGF - DGF  
 eta   60817.        -0.039        -0.061         0.170
 eta   60818.        -0.087        -0.090         0.231
 eta   60819.        -0.084        -0.207         0.305
 eta   60820.         0.025        -0.264         0.379
 eta   60821.        -0.003        -0.170         0.397
Etalon-1 ITT - DGF  
 eta   60817.       -10.032        -4.890        40.945
 eta   60818.        -6.952       -13.542        53.311
 eta   60819.        -0.859       -23.873        75.165
 eta   60820.         0.246        -3.233        85.122
Etalon-2 SGF - ITT  
 etb   60817.         8.824        19.086        53.702
 etb   60818.         6.123       -15.343        36.430
 etb   60819.         2.715       -18.100        34.654
 etb   60820.        -9.137       -28.767        32.334
Etalon-2 SGF - DGF  
 etb   60817.        -0.042         0.046        -0.010
 etb   60818.        -0.096        -0.037        -0.029
 etb   60819.        -0.148        -0.164        -0.012
 etb   60820.        -0.079        -0.320        -0.012
 etb   60821.         0.088        -0.373        -0.036
Etalon-2 ITT - DGF  
 etb   60817.        -8.866       -19.041       -53.712
 etb   60818.        -6.219        15.306       -36.459
 etb   60819.        -2.863        17.936       -34.666
 etb   60820.         9.058        28.447       -32.347
Larets SGF - ITT    
 lar   60817.         2.581        -0.393         0.356
 lar   60818.         2.628         2.487         1.146
 lar   60819.         1.248         4.850         2.749
 lar   60820.         3.108        10.372         2.167
Larets SGF - DGF    
 lar   60817.         0.935        -4.241        -1.272
 lar   60818.         1.721        -9.086        -1.749
 lar   60819.         3.954       -14.108        -3.910
 lar   60820.         2.721       -26.859        -2.565
 lar   60821.         7.866       -35.730        -6.061
Larets ITT - DGF    
 lar   60817.        -1.646        -3.848        -1.628
 lar   60818.        -0.907       -11.573        -2.895
 lar   60819.         2.706       -18.958        -6.660
 lar   60820.        -0.386       -37.230        -4.733
LARES SGF - ITT     
 las   60817.         3.292         0.474        -2.396
 las   60818.         3.390         0.932        -2.397
 las   60819.         3.840         2.070        -2.823
 las   60820.         4.252         2.821        -3.205
LARES SGF - DGF     
 las   60817.         0.016         0.260         0.085
 las   60818.         0.059         0.275         0.120
 las   60819.         0.085         0.268         0.088
 las   60820.         0.054         0.261         0.227
 las   60821.         0.080         0.314         0.170
LARES ITT - DGF     
 las   60817.        -3.276        -0.214         2.481
 las   60818.        -3.331        -0.658         2.517
 las   60819.        -3.755        -1.802         2.911
 las   60820.        -4.197        -2.560         3.432
LARES-2 SGF - DGF   
 la2   60817.        -0.010         0.046        -0.008
 la2   60818.        -0.012         0.036         0.015
 la2   60819.        -0.014         0.041         0.013
 la2   60820.        -0.034         0.017         0.002
 la2   60821.        -0.021         0.038         0.079
LAGEOS-1 SGF - ITT  
 lga   60817.         4.675        -0.287        -0.835
 lga   60818.         3.634         1.277        -1.598
 lga   60819.         4.226         4.452         0.556
 lga   60820.         6.308         4.590        -1.931
LAGEOS-1 SGF - DGF  
 lga   60817.         0.002        -0.187        -0.003
 lga   60818.        -0.019        -0.232        -0.004
 lga   60819.        -0.031        -0.351        -0.033
 lga   60820.        -0.043        -0.327        -0.031
 lga   60821.        -0.011        -0.426        -0.041
LAGEOS-2 SGF - ITT  
 lgb   60817.         3.626        -5.060        -2.868
 lgb   60818.         4.700       -10.231        -2.038
 lgb   60819.         4.045       -13.436        -2.378
 lgb   60820.         3.495       -20.290        -5.160
LAGEOS-2 SGF - DGF  
 lgb   60817.         0.021        -0.015        -0.041
 lgb   60818.         0.024        -0.172        -0.006
 lgb   60819.         0.011        -0.240         0.018
 lgb   60820.         0.026        -0.540        -0.003
 lgb   60821.         0.087        -0.769        -0.049
Stella SGF - ITT    
 ste   60817.         3.866         1.327        -2.146
 ste   60818.         3.514         3.189        -1.864
 ste   60819.         3.693         5.098        -1.816
 ste   60820.         3.726         8.220        -1.898
Stella SGF - DGF    
 ste   60817.         0.235         0.002        -0.302
 ste   60818.         0.429         1.173        -0.633
 ste   60819.         0.487         2.832        -0.701
 ste   60820.         1.043         3.683        -1.353
 ste   60821.         0.553         5.934        -1.022
Stella ITT - DGF    
 ste   60817.        -3.631        -1.324         1.843
 ste   60818.        -3.085        -2.015         1.231
 ste   60819.        -3.205        -2.267         1.115
 ste   60820.        -3.485        -3.638         1.220
Starlette SGF - ITT 
 str   60817.         1.449         1.099        -2.047
 str   60818.         1.222         1.204        -2.012
 str   60819.         1.335         3.203        -1.921
 str   60820.         1.220         5.180        -1.702
Starlette SGF - DGF 
 str   60817.        -0.125         0.963         0.028
 str   60818.        -0.251         2.124         0.144
 str   60819.        -0.405         3.879         0.264
 str   60820.        -0.899         6.578         0.608
 str   60821.        -0.537         9.975         0.861
Starlette ITT - DGF 
 str   60817.        -1.574        -0.136         2.075
 str   60818.        -1.473         0.919         2.156
 str   60819.        -1.740         0.676         2.186
 str   60820.        -1.689         1.297         2.307