Measurement Time Bias

These inputs allow the user to apply a measurement time tag bias to the measurements for which this satellite is a space-based tracker, and optionally simulate and estimate that time tag bias. The same time tag bias will apply to all measurements from this one satellite tracker with these caveats:

  1. If a time tag bias is applied it will apply to all measurement types except EPH POS and EPH VEL measurement types.
  2. The time bias will not be estimated for EPH POS and EPH VEL measurement types.
  3. Estimation applies to filter, smoother, and VLS. Currently, cannot estimate this bias with Least Squares.
Measurement Time Bias Options
Control Description
Estimate

If set to true the time tag bias will be estimated using the stochastic model defined by the "TimeBiasModel" parameter.
TimeBiasModel

The stochastic sequence to model and estimate the time bias. Note that a non-zero "Constant" value will be applied even if the Estimate flag is false.

Choices for the TimeBiasModel include:

  • GaussMarkov = Bias will be modeled as a scalar exponential Gauss Markov sequence.
  • RandomWalk = Bias will be modeled using a Wiener (Brownian motion) sequence.
  • Vasicek = Bias will be modeled using a Vasicek stochastic sequence. This is a two-parameter model that solves for both a short-term and long-term bias.

Reference the Stochastic Models section for the description and inputs associated with each model.