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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   57866.         0.426        -4.663        -0.031
 aji   57867.         0.430        -6.764         0.110
Ajisai ITT - JAX    
 aji   57866.        -0.620         0.779         0.265
 aji   57867.        -0.611         0.889         0.171
 aji   57868.        -0.601         1.322         0.214
Ajisai JAX - SGF    
 aji   57866.         0.194         3.884        -0.234
 aji   57867.         0.181         5.875        -0.280
Beacon-C SGF - ITT  
 bec   57866.        -0.648       -34.927         0.119
 bec   57867.        -0.649       -96.414        -0.526
 bec   57868.        -5.921      -208.057         2.419
 bec   57869.       -13.995      -396.754        11.692
Cyrosat-2 ESA - ITT 
 cyb   57866.         1.111       -10.449        -1.923
 cyb   57867.        -5.385       -15.333         2.524
 cyb   57868.         1.658       -29.725        -3.639
Etalon-1 SGF - ITT  
 eta   57866.         2.878         0.109        -4.777
 eta   57867.         3.449         2.325        -7.240
 eta   57868.         4.662         2.136        -6.188
 eta   57869.         0.808         1.302        -2.253
Etalon-2 SGF - ITT  
 etb   57866.         2.658         1.492         0.108
 etb   57867.         3.216         2.895         0.190
 etb   57868.         2.849         4.577         0.560
 etb   57869.         1.854         5.393         1.243
Jason-2 SGF - ITT   
 jsb   57866.        -0.322       -12.643         4.969
 jsb   57867.         2.246       -30.622         6.279
 jsb   57868.         1.364       -60.638         9.939
 jsb   57869.       -15.433      -103.992        25.802
Jason-2 ITT - CNES  
 jsb   57866.        -0.890         7.719         0.341
 jsb   57867.        -2.471        17.164         1.792
 jsb   57868.        -2.025        33.690         2.074
 jsb   57869.         7.192        57.539        -4.507
Jason-2 CNES - SGF  
 jsb   57866.         1.212         4.924        -5.309
 jsb   57867.         0.225        13.459        -8.071
 jsb   57868.         0.661        26.947       -12.013
 jsb   57869.         8.240        46.453       -21.296
Larets SGF - ITT    
 lar   57866.        -0.383         7.285        -0.710
 lar   57867.         0.480        16.317        -2.115
 lar   57868.         2.462        31.334        -5.073
 lar   57869.        -9.602        45.964         2.598
LARES SGF - ITT     
 las   57866.        -1.984       -12.548         0.126
 las   57867.         0.098       -26.893        -2.726
 las   57868.        -6.956       -61.580         3.321
 las   57869.       -10.007      -103.462        -0.261
LAGEOS-1 SGF - ITT  
 lga   57866.         2.281         0.249        -0.709
 lga   57867.         2.379         2.430        -0.985
 lga   57868.         2.403         1.261        -0.596
 lga   57869.         3.849         6.434        -1.976
LAGEOS-1 ITT - JAX  
 lga   57866.        -2.262        -0.154         0.720
 lga   57867.        -2.355        -2.291         0.992
 lga   57868.        -2.397        -1.197         0.609
LAGEOS-1 JAX - SGF  
 lga   57866.        -0.019        -0.095        -0.012
 lga   57867.        -0.024        -0.139        -0.007
 lga   57868.        -0.005        -0.064        -0.014
LAGEOS-2 SGF - ITT  
 lgb   57866.         1.300         1.469        -1.319
 lgb   57867.         1.138         2.632        -1.862
 lgb   57868.         1.508         3.069        -1.520
 lgb   57869.         1.204         4.922        -2.373
LAGEOS-2 ITT - JAX  
 lgb   57866.        -1.272        -1.377         1.321
 lgb   57867.        -1.157        -2.442         1.905
 lgb   57868.        -1.460        -2.790         1.519
LAGEOS-2 JAX - SGF  
 lgb   57866.        -0.028        -0.093        -0.002
 lgb   57867.         0.019        -0.190        -0.043
 lgb   57868.        -0.047        -0.279         0.001
Stella SGF - ITT    
 ste   57866.         1.441         1.412        -1.258
 ste   57867.         1.147         2.365        -1.207
 ste   57868.         0.561         1.527        -0.852
 ste   57869.         0.342         0.164        -0.623
Starlette SGF - ITT 
 str   57866.         0.565        -4.807        -0.053
 str   57867.         0.488        -7.696         0.208