VisibilitySegment Object

Description

The VisibilitySegment object allows users to determine whether an observer can see a target, based on the user-specified configuration for occulting bodies, celestial object shape models, and refraction.

Inheritance Hierarchy: ObjectàVisibilitySegment

Available In Editions:

Engineer

Mission

Timing Precision Mode

This page describes functionality in millisecond timing precision mode.

Name	Description
Active	If this VisibilitySegment is a child object of a VisibilityCalculator, this property detemines whether the VisibilityCalculator will consider this segment when evaluating the VisibilityCalculator.Visibility() and VisibilityCalculator.VisibilityTimes() methods.
CelestialObjectOccultationModel	Determines how CelestialObject occultations are modeled.
CelestialObjectTargetModel	Determines how CelestialObject targets are modeled.
DeclaredName	The name of the object as declared.
Label	A label for this segment. This label can be set when creating a segment using the VisibilityCalculator.AddSegment() method. The label can also be used to retrieve a particular segment using the VisibilityCalculator.GetSegmentByLabel() method.
Name	The name displayed for this object in output windows such as views, plots, and reports.
ObjectId	The unique identifier for the object.
ObjectType	The type of the object.
Observer	The observer object for this segment.
OccultingBodies	The occulting bodies to consider in visibility calculations. The VisibilitySegment.CelestialObjectOccultationModel property controls the shape model for the occulting bodies when calculating visibility.
OccultingTerrain	The occulting terrain to consider in visibility calculations.
RefractionFrequency	Specifies the frequency that will be used in refraction calculations. Allowed values are in the radio (100 MHz - 100 GHz) or visible (176.3485 THz - 999.3081 THz) frequency bands. The refraction model use is specified using the VisibilitySegment.RefractionModelType property. This RefractionFrequency property is not used if the VisibilitySegment.RefractionModelType is set to "Analytic - TRORD", "Numeric - Exponential", or "None".
RefractionModelType	Specifies the refraction model to be used in computing this VisibilitySegment. Most of the available refraction models use the VisibilitySegment.RefractionFrequency value as an input. Descriptions of the models and a list of references are provided in the Help File. The "Analytic - Chapman" and "Analytic - TRORD" models are only allowed when the observing object is a GroundStation. The "Analytic - TRORD" model uses the local-mean coefficients for each month specified by the GroundStation.RefractivityNs property of the observing GroundStation. The "Analytic - TRORD" and "Numeric - Exponential" models do not use the VisibilitySegment.RefractionFrequency setting.
Target	The target object for this segment.

Name	Description
AddOccultingBody	Adds one or more CelestialObjects to use for occultation modeling.
AddOccultingTerrain	Adds one or more Terrain objects to use for occultation modeling.
Azimuth	Calculates the azimuth of the target with respect to the observer. The angle is referenced to the X-Y plane of the observer's body frame and ranges from 0 to 360 degrees.
CalculateRefraction	Returns the difference in elevation due to the effects of refraction.
ClearSavedStates	Clears previous saved states for this object.
Elevation	Calculates the elevation of the target with respect to the observer. The angle is referenced from the X-Y plane of the observer's body frame and ranges from -90 to 90 degrees.
ElevationTimes	Detects start of visibility (AOS), end of visibility (LOS), and maximum elevation events and determines the elevation at the time of these events.
GetFromFile	Load the object state from the specified FreeFlyer object file.
GetFromString	Load the object state from the specified string.
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.
ReferenceEquals	Returns 1 if the argument refers to the calling object and 0 otherwise.
RemoveAllOccultingBodies	Removes all occulting bodies.
RemoveAllOccultingTerrain	Removes all occulting bodies.
RemoveOccultingBody	Removes the specified bodies from the list of bodies used for occultation modeling.
RemoveOccultingTerrain	Removes the specified Terrain objects from the list of Terrain objects used for occultation modeling.
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.
SetObserver	Sets the observer object for this segment.
SetTarget	Sets the target object for this segment.
Visibility	Evaluates the visibility condition configured by the segment and returns true (1) if the observer can see the target and returns false (0) if the observer can not see the target.
VisibilityTimes	Detects start of visibility (AOS) and end of visibility (LOS) events.