GroundStation.TrackingInterference(Spacecraft, Variable, Spacecraft, TimeSpanArray, Array) Method

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Description

Returns the number of elements that have been populated into the EventTime and EventType arrays. The arrays are populated with the time and type of interference events, where an event can be the start or end of an interference between the GroundStation and the trackedSpacecraft due to interferingSpacecraft.

 

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.

 

Timing Precision Mode

This page describes functionality in nanosecond timing precision mode.

Click here to see the documentation for this object in millisecond timing precision mode.

 

Note: This is an interval method. See the Interval Methods page for more information.

Note: This method has a state. See the Methods and Properties with State page for more information.

 

Method Signature

GroundStation.TrackingInterference(

Spacecraft trackedSpacecraft,

Variable interferenceAngle,

Spacecraft interferingSpacecraft,

TimeSpanArray EventTime,

Array EventType)

 

 

Arguments

trackedSpacecraft

Description:

The Spacecraft to be tracked by the GroundStation.

 

 

interferenceAngle

Description:

The cone half angle about the GroundStation-to-Spacecraft vector used to determine interference.

Units:

deg

Valid Range:

-360 ≤ interferenceAngle ≤ 360

 

 

interferingSpacecraft

Description:

The interfering Spacecraft(s).

Repeatable:

1 to 30 times

 

 

EventTime

Description:

The time that the event occurred.

 

The FF_Preferences.IntervalEventReportingBehavior property controls whether the start of propagation is reported as an event. By default, if the interference starts before the beginning of the propagation span, FreeFlyer will label the start of the propagation as the start of the interference.

 

 

EventType

Description:

The type of the event that occurred. Event Type == 1 is beginning of interference. Event Type == 2 is end of interference.

 

 

 

Return Value

Type:

number

 

 

Returns the number of elements populated into EventType and EventTime arrays

 

Syntax

myVariable1 = myGroundStation1.TrackingInterference(mySpacecraft1, myVariable2, mySpacecraft2, myTimeSpanArray1, myArray1);

 

 

Example 1

This example demonstrates how to generate a report of a GroundStation's tracking interference of a Spacecraft with another Spacecraft.

 

Spacecraft Spacecraft1;

Spacecraft Spacecraft2;

GroundStation GroundStation1;

 

Variable i;

Variable InterferenceTimes;

TimeSpanArray EventTime;

Array EventType;

String gsEventType;

String gsEventTime;

DataTableWindow gsReport({gsEventType, gsEventTime});

 

While (Spacecraft1.ElapsedTime < TIMESPAN(1 days));

 

          InterferenceTimes = GroundStation1.TrackingInterference(Spacecraft1, 90 /* Interference Angle */, Spacecraft2, EventTime, EventType);

 

           If(InterferenceTimes > 0) then;

               For i = 0 to InterferenceTimes -1 step 1;

                           Switch (EventType[i]);

                               Case 1:

                                   gsEventType = "Start of Tracking Interference: ";

                                   gsEventTime = EventTime[i].ConvertToCalendarDate();

                                   Update gsReport;

                                   Break;

                               Case 2:

                                   gsEventType = "End of Tracking Interference: ";

                                   gsEventTime = EventTime[i].ConvertToCalendarDate();

                                   Update gsReport;

                           End;

               End;

           End;

 

           Step Spacecraft1;

           Step Spacecraft2 to (Spacecraft2.Epoch == Spacecraft1.Epoch);

 

End;

 

 

Output:

 

EventType

EventTime

Start of Tracking Interference:

End of Tracking Interference:

Start of Tracking Interference:

End of Tracking Interference:

Start of Tracking Interference:

End of Tracking Interference:

Start of Tracking Interference:

End of Tracking Interference:

Jan 01 2020 06:19:55.825195312

Jan 01 2020 06:27:47.944335937

Jan 01 2020 07:57:38.129882812

Jan 01 2020 08:05:20.727539062

Jan 01 2020 17:21:38.144531250

Jan 01 2020 17:27:06.269531250

Jan 01 2020 18:57:14.692382812

Jan 01 2020 19:06:15.878906250

 

 

 

See also

GroundStation Object

GroundStation.TrackingInterference

Coverage and Contact Analysis Guide

GroundStations Guide