Least Squares Output

The following output options can be set for the LS run:

LS Output Options
Parameter Description
Filename Click in the value column to display a selection window in which you can specify a path and file name (*.lsrun) for LS output.
ResidualArchiving

This property lets you control how much data is written to the output summary file that LS creates when it runs. Options are:

  • All Iterations - The file contains detailed information about each measurement processed for every iteration in the LS process, plus summaries of residuals for each iteration for each measurement type.
  • Initial and Final - The file contains detailed residual information for measurements only for the first and last iterations, plus the summaries. NOTE: if the LS process fails to converge, only the Initial iteration residuals are printed.
  • Summaries Only - The file contains only the summaries for each iteration, and not any of the detailed measurement residuals.
OutputStateHistory

Option to output a satellite state to the .lsrun file. If the satellite state is written then the .lsrun file can be differenced with the filter, smoother, and/or simulator. Also, in any given run, only the state from a single iteration can be output.

  • Last Iteration - Output the state from the last iteration
  • First Iteration - Output the state from the first iteration
  • false - do not output state
SuccessfulRun A read-only field that indicates whether LS processing has been run successfully (true) or not (false).
OrbitState Set the OrbitState property to Cartesian or Keplerian, as desired. Read-only fields will display changes in the orbit state when LS is run.
ForceModelList Shows the force model parameter estimates resulting from the LS Run. For each force model parameter (such as ballistic coefficient and solar pressure coefficient), a flag indicating if the parameter is estimated, the original value, computed correction, the final value and the uncertainty in the final value are displayed. The estimation of force model parameters is controlled by the satellite settings and the EstimateBCoeff and EstimateCr settings in the LeastSquares Stages list.
MeasBiasList Shows the measurement bias estimates resulting from the LS Run. For each estimated bias, the original value, computed correction and final value are displayed. Only the Measurement Biases solved for are displayed. The estimation of measurement biases is controlled by the measurement statistics of tracker objects (facilities and satellites) and the EstimateMeasBias setting in the LeastSquares Stages list.
STKEphemeris

Configure the STKEphemeris attribute to output the ephemeris for each satellite over the LS fit span, or during a prediction period starting at the end of the fit span, or both, written to the specified output directory as


Sat_<satname>_LS_<Stage#>_<Iteration#>_<TIME>.e


Where TIME is:

  • Process start, which is the start time of the current stage
  • Process stop, which is the end time of the current stage
  • Predict start, which is the end time of the current stage
  • Predict stop, which is the prediction end time

The ephemeris is the reference ephemeris used during least squares for generating residuals. To see a read-only list of all ephemeris files created for this least squares object, click next to the Files property.

StatesToTransfer Provides controls for which solved for states will be transferred back to the Satellite during the Transfer To Satellite operation. Estimation state options include the Position/Velocity of the satellite, solved for drag states and solved for solar pressure states. There is also an option to transfer the Position/Velocity covariance from the least squares solution. If selected, scale factors for position and velocity state uncertainties may be applied during the transfer process to help account for the generally optimistic nature of covariance computed during least squares estimation. Scale factors are specified in sigma space meaning that they will be squared for application to the covariance matrix. Finally, the solution state may be transitioned to a different time prior to being transferred to the satellite. By default, the transfer epoch will be set the same as the solution epoch, but it can also be set to the beginning, end or midpoint of the final processing stage or to a user defined time. Covariance scaling is performed after the transition from the solution epoch to the transfer epoch.

Note: Measurement bias solutions cannot currently be transferred.
TransBiasList Shows the transponder bias estimates resulting from the LS Run. For each estimated bias, the original value, computed corrections, and final value are displayed. Only the transponder biases solved for are displayed.

ODTK 6.5