Station Motion Model

The Station Motion Model implements a complete station motion model based on IERS Technical Note 32 (IERS Conventions 2003). This model includes the effects of tectonic plate motion, solid Earth tides, ocean tide loading, and the pole tide. To use the model, set the following attributes in the Object Properties window for a facility:

Property Description
PositionType

Select from the following options:

  • TideFree indicates that ODTK will interpret the input position of the facility as a Conventional Tide Free position.
  • MeanTide indicates that ODTK will interpret the input position of the facility as a Mean Tide position.

The relationship between the Tide Free and Mean Tide positions is given by IERS Technical Note 32 (IERS Conventions 2003), section 7.1.3.
ModelStationMotion Select "true" to enable the station motion model, which accounts for station location variation due to tectonic plate motion, solid Earth tide effects, ocean tide loading effects and the tidal effects due to pole wander. The station motion model follows IERS Technical Note 32 (IERS Conventions 2003), chapter 7. If you select "false", ODTK uses the Mean Tide position, either as input or as computed from an input Tide Free position, for the purpose of measurement modeling.
MotionModel.PlateMotion Select "true" to model the effects of tectonic plate motion. This model requires the input of an epoch for the given station location and a constant velocity in terms of cm/year.
MotionModel.Epoch This is the epoch for the input position of facility, used in the computation of the tectonic plate motion.
MotionModel.Velocity This is the velocity due to tectonic plate motion given in Earth-Centered Earth-Fixed coordinates, in units of cm/year.
MotionModel.OceanTideLoading Select "true" to model the effects of ocean tide loading. The model is equivalent to the model specified in IERS Technical Note 32 (IERS Conventions 2003), section 7.1.1. Successful application of the ocean loading model requires that you specify an ocean loading coefficient file.
MotionModel.OceanTideLoadingFile This is the ocean loading coefficient file in HARPOS format. ODTK requires this for the application of ocean loading. You can generate files of the appropriate format through the following website: http://holt.oso.chalmers.se/loading/. Make sure to select the HARPOS format.
MotionModel.SolidEarthTides Select "true" to model the effects of solid Earth tides. Modeling is as specified in IERS Technical Note 32 (IERS Conventions 2003), section 7.1.2.
MotionModel.PoleTide Select "true" to model the effects of the pole tide. Modeling is as specified in IERS Technical Note 32 (IERS Conventions 2003), section 7.1.4.

As exemplified in the accompanying sample of the Ocean Loading file format expected by ODTK, the current implementation assumes one facility per file.