Description

AgAccessConstraint used to access the AccessConstraint attributes

Public Properties

ConstraintName	Property used to access the constraint name.
ConstraintType	Property used to access the constraint type.
ExclIntvl	Exclude Time Intervals
IsPlugin	This property is deprecated. It is now read-only.
MaxRelMotion	Maximum relative motion used in adaptive sampling.
MaxTimeStep	Maximum time step used in adaptive sampling.

Example

Return a list of available constraints

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% IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
constraintArray = accessConstraints.AvailableConstraints; 
 
disp('List of Available Constraints:'); 
for i=1:length(constraintArray) 
   disp(constraintArray{i,1}); 
end

Add and configure a lighting condition access constraint

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% IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
 
% Condition constraint 
light = accessConstraints.AddConstraint('eCstrLighting'); 
light.Condition = 'eDirectSun';

Add and configure a LOS sun exclusion access constraint

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% IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
 
% Angle constraint 
cnstrAngle = accessConstraints.AddConstraint('eCstrLOSSunExclusion'); 
cnstrAngle.Angle = 176.0;

Add and configure a lunar elevation angle access constraint

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% IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
 
minmax = accessConstraints.AddConstraint('eCstrLunarElevationAngle'); 
minmax.EnableMin = true; 
minmax.Min = 11.1; 
minmax.EnableMax = true; 
minmax.Max = 88.8;

Add and configure a sun elevation angle access constraint

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% IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
 
minmax = accessConstraints.AddConstraint('eCstrSunElevationAngle'); 
minmax.EnableMin = true; 
minmax.Min = 22.2; 
minmax.EnableMax = true; 
minmax.Max = 77.7;

Add and configure a third body obstruction access constraint

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% IAgAccessConstraintCollection accessconstraints: Access Constraint collection 
% Get IAgAccessCnstrThirdBody interface 
thirdBodyConstraint = accessConstraints.AddConstraint('eCstrThirdBodyObstruction'); 
 
% AvailableObstructions returns a one dimensional array of obstruction paths 
availableArray = thirdBodyConstraint.AvailableObstructions; 
 
% In this example add all available obstructions 
disp('Available obstructions'); 
for i=1:length(availableArray) 
   disp(availableArray{i,1}); 
   thirdBodyConstraint.AddObstruction(availableArray{i,1}); 
end 
 
% AssignedObstructions returns a one dimensional array of obstruction paths 
assignedArray = thirdBodyConstraint.AssignedObstructions; 
 
disp('Assigned obstructions'); 
for i=1:length(assignedArray) 
    disp(assignedArray{i,1}); 
end

Add and configure an altitude access constraint

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% IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
 
% Attitude constraint 
altitude = accessConstraints.AddConstraint('eCstrAltitude'); 
altitude.EnableMin = true; 
altitude.Min = 20.5;    % km

Add multiple access constraints of the same type to an STK Object

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% IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
 
% Add constraints 
% Only the eCstrApparentTime, eCstrDuration, eCstrGMT, eCstrIntervals, eCstrLocalTime constraint 
% types can be added multiple times to the constraint collection. 
time1 = accessConstraints.AddConstraint('eCstrLocalTime'); 
time1.Min = '00:00:00.000'; 
time1.Max = '23:00:00.000';

Add a Exclusion Zone access constraint

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% IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
excludeZone = accessConstraints.AddNamedConstraint('ExclusionZone'); 
excludeZone.MaxLat = 45; 
excludeZone.MinLat = 15; 
excludeZone.MinLon = -75; 
excludeZone.MaxLon = -35;

Remove all access constraints except for LOS

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% IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
for i=accessConstraints.Count - 1:-1:0 
    constraint = accessConstraints.Item(i).ConstraintName; 
 
    if (strcmp(constraint,'LineOfSight')) == false 
        if (strcmp(constraint,'ThirdBodyObstruction')) 
            thirdBodyConstraint = accessConstraints.GetActiveNamedConstraint('ThirdBodyObstruction'); 
            assignedArray = thirdBodyConstraint.AssignedObstructions; 
 
            for j=1:length(assignedArray) 
                thirdBodyConstraint.RemoveObstruction(assignedArray{j}); 
            end 
 
        elseif (strcmp(constraint,'ExclusionZone')) 
            accessConstraints.GetActiveNamedConstraint('ExclusionZone').RemoveAll; 
 
        else 
            accessConstraints.RemoveNamedConstraint(constraint); 
        end 
    end 
end

Configure the access interval to the availability time span of the object where access is being computed to.

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% IAgStkObjectRoot root: STK Object Model root 
 
satellite = root.GetObjectFromPath('/Satellite/MySatellite'); 
facility = root.GetObjectFromPath('/Facility/MyFacility'); 
access = satellite.GetAccessToObject(facility); 
 
access.AccessTimePeriod = 'eUserSpecAccessTime'; 
accessTimePeriod = access.AccessTimePeriodData; 
 
if (satellite.Vgt.EventIntervals.Contains('AvailabilityTimeSpan')) 
    availabilityTimeSpan = satellite.Vgt.EventIntervals.Item('AvailabilityTimeSpan'); 
    accessTimePeriod.AccessInterval.SetImplicitInterval(availabilityTimeSpan); 
end

GetAccessBetweenObjectsByPath using the output of GetExistingAccesses

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% IAgStkObjectRoot root: STK Object Model root 
scenario = root.CurrentScenario; 
accesses = scenario.GetExistingAccesses(); 
 
[row, col] = size(accesses);  % number of accesses 
 
object1 = accesses{1,1};   % e.g. "Satellite/MySatellite" 
object2 = accesses{1,2};  % e.g.  "Facility/MyFacility" 
computed = accesses{1,3};          % e.g. true  (if access has been computed) 
 
access = scenario.GetAccessBetweenObjectsByPath(object1, object2);

Return a list of available constraints

[Python] Copy Code

# IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
constraintArray = accessConstraints.AvailableConstraints() 
 
print('List of Available Constraints:') 
for i in range(0,len(constraintArray)): 
   print(constraintArray[i])

Add and configure a lighting condition access constraint

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# IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
 
# Condition constraint 
light = accessConstraints.AddConstraint(25) # eCstrLighting 
light.Condition = 0 # eDirectSun

Add and configure a LOS sun exclusion access constraint

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# IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
 
# Angle constraint 
cnstrAngle = accessConstraints.AddConstraint(29) # eCstrLOSSunExclusion 
cnstrAngle.Angle = 176.0

Add and configure a lunar elevation angle access constraint

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# IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
 
minmax = accessConstraints.AddConstraint(30) # eCstrLunarElevationAngle 
minmax.EnableMin = True 
minmax.Min = 11.1 
minmax.EnableMax = True 
minmax.Max = 88.8

Add and configure a sun elevation angle access constraint

[Python] Copy Code

# IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
 
minmax = accessConstraints.AddConstraint(58) # eCstrSunElevationAngle 
minmax.EnableMin = True 
minmax.Min = 22.2 
minmax.EnableMax = True 
minmax.Max = 77.7

Add and configure a third body obstruction access constraint

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# IAgAccessConstraintCollection accessconstraints: Access Constraint collection 
# Get IAgAccessCnstrThirdBody interface 
thirdBodyConstraint = accessConstraints.AddConstraint(61) # eCstrThirdBodyObstruction 
 
# AvailableObstructions returns a one dimensional array of obstruction paths 
availableArray = thirdBodyConstraint.AvailableObstructions 
 
# In this example add all available obstructions 
print('Available obstructions') 
for i in range(0,len(availableArray)): 
   print(availableArray[i]) 
   thirdBodyConstraint.AddObstruction(availableArray[i]) 
 
# AssignedObstructions returns a one dimensional array of obstruction paths 
assignedArray = thirdBodyConstraint.AssignedObstructions 
 
print('Assigned obstructions') 
for i in range(0,len(assignedArray)): 
    print(assignedArray[i])

Add and configure an altitude access constraint

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# IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
 
# Attitude constraint 
altitude = accessConstraints.AddConstraint(2) # eCstrAltitude 
altitude.EnableMin = True 
altitude.Min = 20.5 # km

Add multiple access constraints of the same type to an STK Object

[Python] Copy Code

# IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
 
# Add constraints 
# Only the eCstrApparentTime (4), eCstrDuration (13), eCstrGMT (16), eCstrIntervals (22), eCstrLocalTime (27) constraint 
# types can be added multiple times to the constraint collection. 
time1 = accessConstraints.AddConstraint(27) # eCstrLocalTime 
time1.Min = '00:00:00.000' 
time1.Max = '23:00:00.000'

Add an Exclusion Zone access constraint

[Python] Copy Code

# IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
excludeZone = accessConstraints.AddNamedConstraint('ExclusionZone') 
excludeZone.MaxLat = 45 
excludeZone.MinLat = 15 
excludeZone.MinLon = -75 
excludeZone.MaxLon = -35

Remove all access constraints except for LOS

[Python] Copy Code

# IAgAccessConstraintCollection accessConstraints: Access Constraint collection 
for i in range(accessConstraints.Count-1,0,-1): 
    constraint = accessConstraints.Item(i).ConstraintName 
 
    if (constraint == 'LineOfSight') == False: 
        if (constraint == 'ThirdBodyObstruction'): 
            thirdBodyConstraint = accessConstraints.GetActiveNamedConstraint('ThirdBodyObstruction') 
            assignedArray = thirdBodyConstraint.AssignedObstructions 
 
            for j in range (0,len(assignedArray)): 
                thirdBodyConstraint.RemoveObstruction(assignedArray[j]) 
            end 
 
        elif (constraint == 'ExclusionZone'): 
            accessConstraints.GetActiveNamedConstraint('ExclusionZone').RemoveAll() 
 
        else: 
            accessConstraints.RemoveNamedConstraint(constraint)

Configure the access interval to the availability time span of the object where access is being computed to.

[Python] Copy Code

# IAgStkObjectRoot root: STK Object Model root 
 
satellite = root.GetObjectFromPath('/Satellite/MySatellite') 
facility = root.GetObjectFromPath('/Facility/MyFacility') 
access = satellite.GetAccessToObject(facility) 
 
access.AccessTimePeriod = 2 # eUserSpecAccessTime 
accessTimePeriod = access.AccessTimePeriodData 
 
if (satellite.Vgt.EventIntervals.Contains('AvailabilityTimeSpan')): 
    availabilityTimeSpan = satellite.Vgt.EventIntervals.Item('AvailabilityTimeSpan') 
    accessTimePeriod.AccessInterval.SetImplicitInterval(availabilityTimeSpan)

GetAccessBetweenObjectsByPath using the output of GetExistingAccesses

[Python] Copy Code

# IAgStkObjectRoot root: STK Object Model root 
scenario = root.CurrentScenario 
accesses = scenario.GetExistingAccesses() 
 
size = len(accesses)  # number of accesses 
 
object1 = accesses[0][0]   # e.g. "Satellite/MySatellite" 
object2 = accesses[0][1]  # e.g.  "Facility/MyFacility" 
computed = accesses[0][2]        # e.g. True  (if access has been computed) 
 
access = scenario.GetAccessBetweenObjectsByPath(object1, object2)

CoClasses that Implement IAgAccessConstraint

Name
AgAccessCnstrTimeSlipRange
AgAccessCnstrBackground
AgAccessCnstrGroundTrack
AgAccessCnstrMinMax
AgAccessCnstrCrdnCn
AgAccessCnstrCbObstruction
AgAccessCnstrAngle
AgAccessCnstrCondition
AgAccessCnstrIntervals
AgAccessCnstrObjExAngle
AgAccessCnstrZone
AgAccessCnstrThirdBody
AgAccessCnstrExclZonesCollection
AgAccessCnstrPluginMinMax
AgAccessCnstrAWBCollection
AgAccessCnstrAWB

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