Orbital Parameters Estimation by BLSEstimator class
Hello to you all Orekit Community! I'm developing an Orbit Determination and Time Synchronisation (ODTS) prototype in Java using the BLSEstimator class provided by Orekit. The prototype is configured with the following parameters:
- 1 satellite
- 12 stations
- The BLSEstimator is built with Lavenberg optimizer and a NumericalPropagator
- Estimator threeshold is set to 1e-3
- Range from each station at 10 minutes from the start date are used as ObservableMeasurement
The following parameters are chosen to be estimated:
- 6 Orbital Parameters
- 1 Satellite Clock Offset
- 12 Stations Clock Offset
The problem is that when I call the method .estimate() and I get the last estimation, I see that all the clock offsets are estimated as well as the initial velocities, but the initial position of the satellite is never estimated, even if their corresponding ParameterDrivers have been selected to be estimated. Do you have an idea of what the problem could be? I was thinking that the problem may come from the fact that I have not set the initial partial derivatives, since I thought they would be calculated by the estimator itself.