GroundStation Object

Description

A GroundStation is a tracking station used for determining line of sight contact with a Spacecraft. GroundStation Objects can be placed on any built-in or custom Celestial Body Objects. It is used to compute contact duration, antenna pointing, acquisition of signal (AOS), and loss of signal (LOS) information with a Spacecraft. See the Coverage and Contact Analysis guide for more information. You can assign GroundStation objects using the = operator. This will equalize the GroundStations' properties, but not the properties of the attached GroundAntenna objects.

Inheritance Hierarchy: ObjectàGroundStation

Available In Editions:

Engineer

Mission

Timing Precision Mode

This page describes functionality in millisecond timing precision mode.

Name	Description
Antenna	The Antenna property is used to define the characteristics of tracking data being provided from the ground station. See the Orbit Determination Guide for more information.
CentralBody	The name of the CelestialObject on which the GroundStation is located.
CentralBodyObject	The CelestialObject on which the GroundStation is located.
Color	The color of the GroundStation when visualized in a Mission View. The color can be overridden for an individual view using the ViewWindow.SetObjectColor() method.
ConeElevation	If the MaskShape value is set to 'Cone', this property defines the constant elevation horizon of the groundstation. When MaskShape is 'None' or 'Points', this property is ignored for calculations, but is used for representing the groundstation in the Mission View.
DeclaredName	The name of the object as declared.
DrawMethod	Determines how the GroundStation will be rendered in a Mission View. The draw method can be overridden for an individual view using ViewWindow.SetGroundStationDrawMethod() method.
FixedPosition	Reports the object's position components (X, Y, Z) referenced to the Body Fixed coordinate system of its central body.
GeodeticsFilename	The GroundStation geodetic data file name. The Geodetics file is used for GroundStations with Earth as their central body.
Height	The height of the ground station above the reference ellipsoid. The Earth uses the WGS 84 (World Geodetic System 1984) reference ellipsoid.
InterpolationMode	The Method used to interpolate between defined points of the groundstation mask when the MaskShape is 'points'.
Latitude	The planetodetic latitude of the ground station measured from the equator.
LHCPolarizationSupport	This is a customer requested property. It has no effect on simulation. It is merely a value holder.
LINPolarizationSupport	This is a customer requested property. It has no effect on simulation. It is merely a value holder.
Longitude	The longitude of the ground station east of the prime meridian.
MaskAzimuth	When MaskShape is set to 'Points', the MaskAzimuth value for each of the 'n' points can be set. The array index (i.e., 'n') starts at 0 and goes up to NumberOfPoints - 1.
MaskElevation	When MaskShape is set to 'Points', the MaskElevation value for each of the 'n' points can be set. The array index (i.e., 'n') starts at 0 and goes up to NumberOfPoints - 1.
MaskShape	The type of horizon mask for the ground station. The mask can be defined as a cone, as a series of azimuth and elevation angles, or you can select not to use a mask, in which case the GroundStation can "see" to the horizon.
MonthlyRefractivity	Mean Surface Refractivity (N) based on month of year. These values are used in the 'RC (tick Refraction Correction) model. This refraction setting is only used to determine the tropospheric time/range bias in the Orbit Determination system. Tropospheric corrections are only applied when the Earth is the central body for the GroundStation. This refraction setting is not applied when computing any other contact or visibility methods.
Name	The name displayed for this object in output windows such as views, plots, and reports.
NumberOfPoints	When MaskShape is set to 'Points', this property defines the number points that comprise the masking profile.
ObjectId	The unique identifier for the object.
ObjectType	The type of the object.
OD	This property contains the OD settings for all the GroundStation properties that can be estimated.
Opacity	The opacity of the GroundStation when visualized in a Mission View. This does not apply to the GroundStation outline.The opacity can be overridden for an individual view using ViewWindow.SetObjectOpacity() method.
ReceiverGainTemperature	The receiver gain temperature.
RefractionModelType	Refraction model to use. Refraction can only be computed when the Earth is the central body of the GroundStation. The selected refraction model will be used to compute refracted elevation from this GroundStation, affecting the following methods: GroundStation.ElevationR, GroundStation.CommZAspectAngle, GroundStation.TrackingInterference, Spacecraft.Contact, Spacecraft.ContactTimes, and Spacecraft.PassData. The following refraction models are available: - None. - Analytic - Chapman. This Earth refraction model is based on analytic Chapman theory. - Analytic - Interpolation Table. This model is the same as the VisibilitySegment "Analytic - TRORD" model. This Earth refraction model is based on the TRORD refraction model documented in the "Software Requirements Specification for Tracking and Orbit Determination (TRORD) CPCI 202 of the Command and Control Segment Math Appendix", September 1992. This is a troposphere-only refraction model; ionospheric refraction is not modeled. This model uses the local-mean coefficients for each month specified by the GroundStation.RefractivityNs property. To access additional refraction models, visibility methods, and observer/target object types, use the VisibilityCalculator and VisibilitySegment objects.
RefractivityNs	Local-mean coefficients for each month used with the analytic interpolation table refraction model. If the GroundStation.RefractionModelType is set to "Analytic - Interpolation Table", this array of refraction coefficients is used to compute the refracted elevation from this GroundStation, affecting the following methods: GroundStation.ElevationR, GroundStation.CommZAspectAngle, GroundStation.TrackingInterference, Spacecraft.Contact, Spacecraft.ContactTimes, and Spacecraft.PassData. These refraction coefficients are also used with the VisibilityCalculator and VisibilitySegment objects if this GroundStation is the observer for a Segment and the Segment.RefractionModelType is set to "Analytic - TRORD".
RHCPolarizationSupport	This is a customer requested property. It has no effect on simulation. It is merely a value holder.
SgfStation	An acronym that corresponds to a station in the Station Geodetics file. This property should contain an alpha/numeric string of four characters. The Geodetics file is used for GroundStations with Earth as their central body.
TrackingStationId	A numeric ID which matches the ID within tracking data file(s) associated with this ground station. Note: This property is used in association with Orbit Determination.
TransmitterEIRP	The transmitter EIRP.

Name	Description
Azimuth	Returns the azimuth angle of the argument as seen from the reference object. The definition of azimuth depends on the reference object and the passed arguments.
CelestialObjectWidth	Returns the angular width of the provided CelestialObject as observed from the GroundStation position.
ClearSavedStates	Clears previous saved states for this object.
Elevation	Returns the elevation angle of the argument as seen from the reference object.
ElevationR	Returns the elevation angle of the argument as seen from the reference object. The ElevationR method will account for refraction if refraction modeling is turned on using the GroundStation.RefractionModelType property; otherwise the values returned by the ElevationR method will equal those returned by the Elevation method. To access additional refraction models, visibility methods, and observer/target object types, use the VisibilityCalculator and VisibilitySegment objects.
FixedVectorToObject	Returns an Array containing the components of the vector originating at the location of the prefix object and terminating at the location of the argument object, in the body fixed coordinate frame of the prefix object.
GetElevationAtAzimuth	Returns the elevation of the ground station mask at the specified azimuth.
GetFromFile	Load the object state from the specified FreeFlyer object file.
GetFromString	Load the object state from the specified string.
GetHeight	Returns the bodydetic height. Objects below the surface will return a negative height.
GetPositionAtEpoch	Reports the GroundStation's position components (X, Y, Z) at the specified epoch in the Mean J2000 Earth Equator frame.
InShadow	Returns an integer value indicating whether the GroundStation is in shadow. A value of 1 is returned when the GroundStation is in shadow, and a 0 is returned if it is not. If the GroundStation is below the surface, it will be treated as if it is on the surface.
LoadFromStationGeodeticsFile	Loads a GroundStation configuration from a station geodetics file.
PutToFile	Convert the object state to FreeFlyer object xml and write to a file.
PutToString	Convert the object state to FreeFlyer object xml and return as a string.
Range	Returns the distance between two Vehicles, a Vehicle and a GroundStation, or a Vehicle and a CelestialObject. The Range method requires a single argument, either a Vehicle, a CelestialObject, a CelestialObject BodyID, or a GroundStation object.
RangeRate	Returns the time rate of change of a Spacecraft's range from either a GroundStation or another Spacecraft.
ReferenceEquals	Returns 1 if the argument refers to the calling object and 0 otherwise.
ResetMethodStates	Resets any method states associated with the calling object.
Restore	Restore an object's state from a previously saved state.
Save	Save the object's state so that it can be restored later.
SetCentralBody	Sets the body of the calling object.
SetFixedPosition	Sets the object's position components (X, Y, Z) referenced to the Body Fixed coordinate system of its central body.
SetHeight	Set the object's height.
TrackingInterference	Provides detailed information on the times when a GroundStation tracking a Spacecraft is interfered with by a Star, Celestial Object, or another Spacecraft. Interference occurs when the tracked Spacecraft is visible to the GroundStation, but an interfering object(s) lies within a user-specified cone about the GroundStation-to-Spacecraft vector. FreeFlyer calculates interference based on the times when the center of the interfering object is within the cone. If you want to model a non-zero angular width for an interfering object, you can add half the angular width of that object (as seen from the GroundStation) to the desired interference half-angle to get the total cone half-angle. Note: When more than one interfering object is specified, ALL of these objects (as opposed to ANY) must lie within the interference cone for the tracking to be considered interfered. The TrackingInterference method will account for refraction if refraction modeling is turned on using the GroundStation.RefractionModelType property.
VectorToObject	Returns an Array containing the components of the vector originating at the location of the prefix object and terminating at the location of the argument object, in MJ2000 Earth Equator coordinates.