Description

Configuration options for chains.

Object Model

Public Methods

ClearAccess	Removes all chain accesses.
ComputeAccess	Computes access for the chain.
ResetAccessIntervalsFile	Method to reset the .int file containing the strand access intervals.
SetAccessIntervalsFile	Opt to produce an .int file containing the strand access intervals.
SetTimePeriodType	Method to set the option used to specify the time period.

Public Properties

AccessIntervalsFile	Name of the .int file containing the strand access intervals.
AutoRecompute	Opt to have STK automatically recompute accesses each time that an object on which the chain depends is updated.
Constraints	Get the constraints applicable to the chain.
DataSaveMode	Specify the mode for saving or recomputing accesses.
DetectEventsBasedOnSamplesOnly	Flags control whether event times are computed just using the sampling or by sub-sampling
EnableLightTimeDelay	Specify whether to take light time delay into account in the computation.
EventDetection	Event detection strategy used for access calculations.
Graphics	Get the 2D graphics properties of the chain.
MaxTimeStep	The maximum sampling step size used when computing the chain. The maximum step size limits the amount of time that is allowed to elapse between sampling of the constraint functions during access computations. Uses Time Dimension.
Objects	Get the collection of objects in the chain.
Sampling	Sampling method used for access calculations.
TimeConvergence	The time convergence for determining access intervals when computing the chain. Uses Time Dimension.
TimePeriod	The time period for the chain.
TimePeriodType	Get the option used to specify the time period for the chain.
VO	Get the 3D graphics properties of the chain.

Example

Create a chain (on the current scenario central body)

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// Create the Chain on the current scenario central body (use 

// NewOnCentralBody to specify explicitly the central body) 

IAgChain chain = root.CurrentScenario.Children.New(AgESTKObjectType.eChain, "MyChain") as IAgChain;

Define and compute a chain (basic)

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// Add some objects to chain (using STK path) 

chain.Objects.Add("Facility/fac1"); 

chain.Objects.Add("Satellite/sat1"); 

chain.Objects.Add("Satellite/sat2"); 

chain.Objects.Add("Aircraft/air1"); 

 

// Compute the chain 

chain.ComputeAccess();

Define and compute a chain (advance)

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// Remove all previous accesses 

chain.ClearAccess(); 

 

// Add some objects to chain 

chain.Objects.Add("Facility/fac1"); 

chain.Objects.Add("Satellite/sat1"); 

chain.Objects.Add("Satellite/sat2"); 

chain.Objects.Add("Aircraft/air1"); 

 

// Configure chain parameters 

chain.AutoRecompute = false; 

chain.EnableLightTimeDelay = false; 

chain.TimeConvergence = 0.001; 

chain.DataSaveMode = AgEDataSaveMode.eSaveAccesses; 

 

// Specify our own time period 

chain.SetTimePeriodType(AgEChTimePeriodType.eUserSpecifiedTimePeriod); 

 

// Get chain time period interface 

IAgChUserSpecifiedTimePeriod chainUserTimePeriod = chain.TimePeriod as IAgChUserSpecifiedTimePeriod; 

chainUserTimePeriod.SetTimePeriod("1 Jul 2005 12:00:00", "2 Jul 2005 12:00:00"); 

 

// Compute the chain 

chain.ComputeAccess();

Configure the chain compute time period.

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chain.SetTimePeriodType(AgEChTimePeriodType.eUserSpecifiedTimePeriod); 

IAgChUserSpecifiedTimePeriod userSpecifiedTimePeriod = chain.TimePeriod as IAgChUserSpecifiedTimePeriod; 

userSpecifiedTimePeriod.TimeInterval.SetExplicitInterval("1 May 2015 04:00:00.000", "1 May 2015 05:00:00.000");

Prints the strand intervals of chain object

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IAgStkObject chainAsStkObject = chain as IAgStkObject; 

 

// Compute the chain access if not done already. 

chain.ComputeAccess(); 

 

// Considered Start and Stop time 

Console.WriteLine("Chain considered start time: {0}", chainAsStkObject.Vgt.Events["ConsideredStartTime"].FindOccurrence().Epoch); 

Console.WriteLine("Chain considered stop time: {0}", chainAsStkObject.Vgt.Events["ConsideredStopTime"].FindOccurrence().Epoch); 

 

IAgCrdnEventIntervalCollection objectParticipationIntervals = chainAsStkObject.Vgt.EventIntervalCollections["StrandAccessIntervals"]; 

IAgCrdnIntervalsVectorResult intervalListResult = objectParticipationIntervals.FindIntervalCollection(); 

 

for (int i = 0; i < intervalListResult.IntervalCollections.Count; ++i) 

{ 

    if (intervalListResult.IsValid) 

    { 

        Console.WriteLine("Link Name: {0}", objectParticipationIntervals.Labels.GetValue(i)); 

        Console.WriteLine("--------------"); 

        for (int j = 0; j < intervalListResult.IntervalCollections[i].Count; ++j) 

        { 

            object startTime = intervalListResult.IntervalCollections[i][j].Start; 

            object stopTime = intervalListResult.IntervalCollections[i][j].Stop; 

            Console.WriteLine("Start: {0}, Stop: {1}", startTime, stopTime); 

        } 

    } 

}

Create a chain (on the current scenario central body)

[Visual Basic .NET] Copy Code

' Create the Chain on the current scenario central body (use
' NewOnCentralBody to specify explicitly the central body)
Dim chain As IAgChain = TryCast(root.CurrentScenario.Children.[New](AgESTKObjectType.eChain, "MyChain"), IAgChain)

Define and compute a chain (basic)

[Visual Basic .NET] Copy Code

' Add some objects to chain (using STK path)
 chain.Objects.Add("Facility/fac1")
 chain.Objects.Add("Satellite/sat1")
 chain.Objects.Add("Satellite/sat2")
 chain.Objects.Add("Aircraft/air1")

' Compute the chain
 chain.ComputeAccess()

Define and compute a chain (advance)

[Visual Basic .NET] Copy Code

' Remove all previous accesses
 chain.ClearAccess()

' Add some objects to chain
 chain.Objects.Add("Facility/fac1")
 chain.Objects.Add("Satellite/sat1")
 chain.Objects.Add("Satellite/sat2")
 chain.Objects.Add("Aircraft/air1")

' Configure chain parameters
 chain.AutoRecompute = False
 chain.EnableLightTimeDelay = False
 chain.TimeConvergence = 0.001
 chain.DataSaveMode = AgEDataSaveMode.eSaveAccesses

' Specify our own time period
 chain.SetTimePeriodType(AgEChTimePeriodType.eUserSpecifiedTimePeriod)

' Get chain time period interface
Dim chainUserTimePeriod As IAgChUserSpecifiedTimePeriod = TryCast(chain.TimePeriod, IAgChUserSpecifiedTimePeriod)
 chainUserTimePeriod.SetTimePeriod("1 Jul 2005 12:00:00", "2 Jul 2005 12:00:00")

' Compute the chain
 chain.ComputeAccess()

Configure the chain compute time period.

[Visual Basic .NET] Copy Code

chain.SetTimePeriodType(AgEChTimePeriodType.eUserSpecifiedTimePeriod)
Dim userSpecifiedTimePeriod As IAgChUserSpecifiedTimePeriod = TryCast(chain.TimePeriod, IAgChUserSpecifiedTimePeriod)
 userSpecifiedTimePeriod.TimeInterval.SetExplicitInterval("1 May 2015 04:00:00.000", "1 May 2015 05:00:00.000")

Prints the strand intervals of chain object

[Visual Basic .NET] Copy Code

Dim chainAsStkObject As IAgStkObject = TryCast(chain, IAgStkObject)

' Compute the chain access if not done already.
 chain.ComputeAccess()

' Considered Start and Stop time
 Console.WriteLine("Chain considered start time: {0}", chainAsStkObject.Vgt.Events("ConsideredStartTime").FindOccurrence().Epoch)
 Console.WriteLine("Chain considered stop time: {0}", chainAsStkObject.Vgt.Events("ConsideredStopTime").FindOccurrence().Epoch)

Dim objectParticipationIntervals As IAgCrdnEventIntervalCollection = chainAsStkObject.Vgt.EventIntervalCollections("StrandAccessIntervals")
Dim intervalListResult As IAgCrdnIntervalsVectorResult = objectParticipationIntervals.FindIntervalCollection()

Dim i As Integer = 0
While i <>
     If intervalListResult.IsValid Then
         Console.WriteLine("Link Name: {0}", objectParticipationIntervals.Labels.GetValue(i))
         Console.WriteLine("--------------")
         Dim j As Integer = 0
         While j <>
             Dim startTime As Object = intervalListResult.IntervalCollections(i)(j).Start
             Dim stopTime As Object = intervalListResult.IntervalCollections(i)(j).[Stop]
             Console.WriteLine("Start: {0}, Stop: {1}", startTime, stopTime)
             System.Threading.Interlocked.Increment(j)
         End While
     End If
     System.Threading.Interlocked.Increment(i)
End While

Create a chain (on the current scenario central body)

[MATLAB] Copy Code

% IAgStkObjectRoot root: STK Object Model Root 
% Create the Chain on the current scenario central body (use 
% NewOnCentralBody to specify explicitly the central body) 
chain = root.CurrentScenario.Children.New('eChain', 'MyChain');

Define and compute a chain (basic)

[MATLAB] Copy Code

% IAgChain chain: Chain object 
 
% Add some objects to chain (using STK path) 
chain.Objects.Add('Facility/MyFacility'); 
chain.Objects.Add('Satellite/MySatellite'); 
 
% Compute the chain 
chain.ComputeAccess();

Define and compute a chain (advance)

[MATLAB] Copy Code

% IAgChain chain: Chain object 
% IAgSatellite satellite: Satellite object 
 
% Remove all previous accesses 
chain.ClearAccess(); 
 
% Add some objects to chain 
chain.Objects.Add('Facility/MyFacility'); 
chain.Objects.AddObject(satellite); 
 
% Configure chain parameters 
chain.AutoRecompute = false; 
chain.EnableLightTimeDelay = false; 
chain.TimeConvergence = 0.001; 
chain.DataSaveMode = 'eSaveAccesses'; 
 
% Specify our own time period 
chain.SetTimePeriodType('eUserSpecifiedTimePeriod'); 
 
% Get chain time period interface 
chainUserTimePeriod = chain.TimePeriod; 
chainUserTimePeriod.SetTimePeriod(root.CurrentScenario.StartTime, root.CurrentScenario.StopTime); % Set to scenario period 
 
% Compute the chain 
chain.ComputeAccess();

Prints the strand intervals of chain object

[MATLAB] Copy Code

% IAgChain chain: Chain Object 
% Compute the chain access if not done already. 
chain.ComputeAccess(); 
 
% Considered Start and Stop time 
disp(['Chain considered start time: ' chain.Vgt.Events.Item('ConsideredStartTime').FindOccurrence.Epoch]); 
disp(['Chain considered stop time: ', chain.Vgt.Events.Item('ConsideredStopTime').FindOccurrence.Epoch]); 
 
objectParticipationIntervals = chain.Vgt.EventIntervalCollections.Item('StrandAccessIntervals'); 
intervalListResult = objectParticipationIntervals.FindIntervalCollection(); 
 
for i = 0:intervalListResult.IntervalCollections.Count -1 
 
    if intervalListResult.IsValid 
 
        disp(['Link Name: ' objectParticipationIntervals.Labels(i+1)]); 
        disp('--------------'); 
        for j = 0:intervalListResult.IntervalCollections.Item(i).Count - 1 
 
            startTime = intervalListResult.IntervalCollections.Item(i).Item(j).Start; 
            stopTime = intervalListResult.IntervalCollections.Item(i).Item(j).Stop; 
            disp(['Start: ' startTime ' Stop: ' stopTime]); 
        end 
    end 
end

Create a chain (on the current scenario central body)

[Python] Copy Code

# IAgStkObjectRoot root: STK Object Model Root 
# Create the Chain on the current scenario central body (use 
# NewOnCentralBody to specify explicitly the central body) 
chain = root.CurrentScenario.Children.New(4, 'MyChain') # eChain

Define and compute a chain (basic)

[Python] Copy Code

# IAgChain chain: Chain object 
 
# Add some objects to chain (using STK path) 
chain.Objects.Add('Facility/MyFacility') 
chain.Objects.Add('Satellite/MySatellite') 
 
# Compute the chain 
chain.ComputeAccess()

Define and compute a chain (advanced)

[Python] Copy Code

# IAgChain chain: Chain object 
# IAgSatellite satellite: Satellite object 
 
# Remove all previous accesses 
chain.ClearAccess() 
 
# Add some objects to chain 
chain.Objects.Add('Facility/MyFacility') 
chain.Objects.AddObject(satellite) 
 
# Configure chain parameters 
chain.AutoRecompute = False 
chain.EnableLightTimeDelay = False 
chain.TimeConvergence = 0.001 
chain.DataSaveMode = 2 # eSaveAccesses 
 
# Specify our own time period 
chain.SetTimePeriodType(2) # eUserSpecifiedTimePeriod 
 
# Get chain time period interface 
chainUserTimePeriod = chain.TimePeriod 
chainUserTimePeriod.SetTimePeriod(root.CurrentScenario.StartTime, root.CurrentScenario.StopTime) # Set to scenario period 
 
# Compute the chain 
chain.ComputeAccess()

Prints the strand intervals of chain object

[Python] Copy Code

# IAgChain chain: Chain Object 
# Compute the chain access if not done already. 
chain.ComputeAccess() 
 
# Considered Start and Stop time 
print('Chain considered start time: #s' # chain.Vgt.Events.Item('ConsideredStartTime').FindOccurrence().Epoch) 
print('Chain considered stop time: #s' # chain.Vgt.Events.Item('ConsideredStopTime').FindOccurrence().Epoch) 
 
objectParticipationIntervals = chain.Vgt.EventIntervalCollections.Item('StrandAccessIntervals') 
intervalListResult = objectParticipationIntervals.FindIntervalCollection() 
 
for i in range(0,intervalListResult.IntervalCollections.Count): 
 
    if intervalListResult.IsValid: 
 
        print('Link Name: #s' # objectParticipationIntervals.Labels(i+1)) 
        print('--------------') 
        for j in range(0,intervalListResult.IntervalCollections.Item(i).Count): 
 
            startTime = intervalListResult.IntervalCollections.Item(i).Item(j).Start 
            stopTime = intervalListResult.IntervalCollections.Item(i).Item(j).Stop 
            print('Start: #s Stop: #s' # (startTime, stopTime))

CoClasses that Implement IAgChain

Name
AgChain

AGI STK Objects 11	Send comments on this topic.
IAgChain Interface