Spacecraft.CloseApproachRange(Variable, GroundStation, Variable) Method

Top

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 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

Spacecraft.CloseApproachRange(	Variable rangeLimit,
	GroundStation rangingStation,
	Variable Algorithm)

Arguments

rangeLimit
Description:	Range that specifies the distance inside of which the closest approach detection is desired and outside of which the greatest separation detection is desired.
Units:	km

rangingStation
Description:	GroundStation object with respect to which range is computed.

Algorithm

Description:

interpolationMethod.

Valid Values:

Value	Label
0	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.
1	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.

Return Value

Type:

string

Returns a sequential listing of events related to the proximity of two objects.

The FF_Preferences.IntervalEventReportingBehavior property controls whether the start and end of propagation are reported as events. 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. If the close approach extends past the end of the propagation span, FreeFlyer labels the end of propagation as the end of the close approach.

Syntax

myString1 = mySpacecraft1.CloseApproachRange(myVariable1, myGroundStation1, myVariable2);