PreprocessingVariationalEquationOrbitFit
This program fits an inputfileVariational to an observed inputfileOrbit by estimating parameters in a least squares adjustment. Additional to the initial satellite state for each arc, these parameters can be parametrizationGravity, satellite parametrizationAcceleration and stochastic pulses (velocity jumps) at given times, stochasticPulse. The estimated parameters can be stored with outputfileSolution and an extra file with the parameter names is created. The fitted orbit is written as new reference in outputfileVariational and additionally in outputfileOrbit.
The observed orbit positions (inputfileOrbit) together with the epoch wise covariance matrix (inputfileCovariancePodEpoch) must be splitted in the same arcs as the variational equations but not necessarily uniform distributed (use irregularData in InstrumentSynchronize). An iterative downweighting of outliers is performed by M-Huber method.
The observation equations (parameter sensitity matrix) are computed by integration of the variational equations (inputfileVariational) using a polynomial with integrationDegree and interpolated to the observation epochs using a polynomial with interpolationDegree.
All parameters used here must be reestimated in the full least squares adjustment for the gravity field determination to get a solution which is not biased towards the reference field. The solution of additional estimations are relative (deltas) as the parameters are already used as Taylor point in the reference orbit.
See also PreprocessingVariationalEquation.
| Name | Type | Annotation |
|---|---|---|
outputfileVariational | filename | approximate position and integrated state matrix |
outputfileOrbit | filename | integrated orbit |
outputfileSolution | filename | estimated calibration and state parameters |
inputfileVariational | filename | approximate position and integrated state matrix |
inputfileOrbit | filename | kinematic positions of satellite as observations |
inputfileCovariancePodEpoch | filename | 3x3 epoch wise covariances |
ephemerides | ephemerides | may be needed by parametrizationAcceleration |
parametrizationGravity | parametrizationGravity | gravity field parametrization |
parametrizationAcceleration | parametrizationAcceleration | orbit force parameters |
stochasticPulse | timeSeries | |
integrationDegree | uint | integration of forces by polynomial approximation of degree n |
interpolationDegree | uint | orbit interpolation by polynomial approximation of degree n |
iterationCount | uint | for the estimation of calibration parameter and error PSD |