ODTK provides the capability to simulate or estimate corrections to selected parameters within the a priori global atmospheric density model. This feature is currently supported for the Jacchia 1970 and JacchiaBowman 2008 atmospheric density models. In addition, plugin density models can advertise parameters which can be estimated.
Global Atmospheric Density Estimation  

Parameter  Description 
Mode  When the Nominal mode is selected, the atmospheric density is computed as prescribed by the a priori model without modification. Select Estimate to generate deviated density values (simulator) or estimate corrections to the selected density model parameters. Simulated density values are generated via random deviations of the selected density model parameters in accordance with their stochastic definition. Select Correct to allow specification of density model parameters via a file. 
Model (Estimate) 
Select the a priori atmospheric density model for which parameter corrections are desired. Currently limited to the Jacchia 1970 and the JacchiaBowman 2008 atmospheric density models and plug in density models which have advertised parameters for estimation. 
Parameterization (Estimate) 
Select the parameters which you desire to simulate or estimate.
When using the builtin Jacchia 1970 or JacchiaBowman 2008 models
the following estimation options are available:
When using a plugin atmospheric density model the following estimation options are available:

EstimationParameters (Estimate)  Provides a list of stochastic parameters which may be modeled as either scalars (corrections have no positional dependence) or as low degree and order spherical harmonic expansions. The spherical harmonic expansions are defined in a reference frame with the Z axis aligned with the Earth Fixed Z axis and the X axis pointed in the direction of the Sun. Note that the same reference frame definition is used regardless of which parameterization is selected. 
CorrectionFilename (Correct)  Name of the file containing corrections to atmospheric density model parameters. You can use a Global Density Correction file (*.gdc). 
LimitCorrectionEpoch (Correct)  Set an artificial limit on the final epoch in the provided data file. 
LastestCorrectionEpoch (Correct)  Artificial limit on the final epoch in the provided data file. When density model parameter corrections are requested at epochs later than this time, the correction values at the LatestCorrectionEpoch are returned. 
ODTK 6.5