Generation of TLE

Orekit development
7

hi guys!
i am doing almost the samething.
given an keplerian orbit
converting into TLE orbit

i read the code in “TLEConverterTest.java”

then i try to write my code as this:

    TLEPropagatorBuilder builder = new TLEPropagatorBuilder(tle, PositionAngle.TRUE, 1.0);

    double threshold = 1.0e-3;
    FiniteDifferencePropagatorConverter fitter = new FiniteDifferencePropagatorConverter(builder, threshold, 1000);
    fitter.convert(samples_ss, false, TLEPropagatorBuilder.B_STAR);
    TLEPropagator prop = (TLEPropagator) fitter.getAdaptedPropagator();
    TLE fitted = prop.getTLE();

in the first line above:
TLEPropagatorBuilder builder = new TLEPropagatorBuilder(tle, PositionAngle.TRUE, 1.0);
it need a tle as the param put into the constructor.

that’s weird. i want to generate a tle, but i need to have a tle fisrt.

i guess maybe the useful info in the tle i need to have first is the following :

Column Description
03-07 Satellite Number
08 Classification (U=Unclassified)
10-11 International Designator (Last two digits of launch year)
12-14 International Designator (Launch number of the year)
15-17 International Designator (Piece of the launch)
|19-20 |Epoch Year (Last two digits of year)
|21-32 |Epoch (Day of the year and fractional portion of the day)

am i right or my concept is wrong?

thanks