Description
Returns a sequential listing of events related to the proximity of the calling Spacecraft and the argument rangingStation using the specified Algorithm.
For more information on the ANCAS algorithms, please refer to: Alfano, Salvatore. Determining Satellite Close Approaches, Part II. Journal of the Astronautical Sciences 42.2. Apr-Jun 1994, 143-152.
Timing Precision Mode
This page describes functionality in millisecond timing precision mode. Millisecond timing precision mode is deprecated and will be removed in a future release. We recommend that you migrate your Mission Plans to nanosecond timing precision mode.
Click here to see the documentation for this object in nanosecond 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
Arguments
rangeLimit
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Description:
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Range that specifies the distance inside of which the closest approach detection is desired and outside of which the greatest separation detection is desired.
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Units:
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km
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rangingStation
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Description:
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GroundStation object with respect to which range is computed.
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Algorithm
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Description:
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interpolationMethod.
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Valid Values:
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Value
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Label
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0
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ANCAS 1 interpolation method. This method uses the position and velocity states from three data points to create a quintic polynomial approximating the range between the two objects over time.
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1
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ANCAS 2 interpolation method. This method uses the position, velocity, and acceleration states from two data points to create a quintic polynomial approximating the range between the two objects over time.
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EventTime
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Description:
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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 close approach starts before the beginning of the propagation span, FreeFlyer will label the start of the propagation as the start of the close approach.
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EventType
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Description:
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The type of the event that occurred.
Event Type == 1 is Range Limit Entry Detected.
Event Type == 2 is Range Limit Exit Detected.
Event Type == 3 is Minimum Range Detected.
Event Type == 4 is Maximum Range Detected.
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EventRange
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Description:
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The range between the two Objects' centers at the epoch when the event occurred.
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Return Value
Returns the number of elements filled into EventType and EventTime arrays.
Syntax
myVariable1 = mySpacecraft1.CloseApproachRange(myVariable2, myGroundStation1, myVariable3, myArray1, myArray2, myArray3);
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See also
Spacecraft Object
Spacecraft.CloseApproachRange
Spacecraft Propagation Guide
Coverage and Contact Analysis Guide
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