Class InterSatDirectViewDetector
- java.lang.Object
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- org.orekit.propagation.events.AbstractDetector<InterSatDirectViewDetector>
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- org.orekit.propagation.events.InterSatDirectViewDetector
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- All Implemented Interfaces:
EventDetector
public class InterSatDirectViewDetector extends AbstractDetector<InterSatDirectViewDetector>
Detector for inter-satellites direct view (i.e. no masking by central body limb).As this detector needs two satellites, it embeds one
coordinates provider
for the secondary satellite and is registered as an event detector in the propagator of the primary satellite. The secondary satellite provider will therefore be driven by this detector (and hence by the propagator in which this detector is registered).In order to avoid infinite recursion, care must be taken to have the secondary satellite provider being completely independent from anything else. In particular, if the provider is a propagator, it should not be run together in a
propagators parallelizer
with the propagator this detector is registered in. It is fine however to configure two separate propagators PsA and PsB with similar settings for the secondary satellite and one propagator Pm for the primary satellite and then use Psa in this detector registered within Pm while Pm and Psb are run in the context of apropagators parallelizer
.For efficiency reason during the event search loop, it is recommended to have the secondary provider be an analytical propagator or an ephemeris. A numerical propagator as a secondary propagator works but is expected to be computationally costly.
The
g
function of this detector is positive when satellites can see each other directly and negative when the central body limb is in between and blocks the direct view.This detector only checks masking by central body limb, it does not take into account satellites antenna patterns. If these patterns must be considered, then this detector can be
and combined
with thelogical not
offield of view detectors
.- Since:
- 9.3
- Author:
- Luc Maisonobe
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Field Summary
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Fields inherited from class org.orekit.propagation.events.AbstractDetector
DEFAULT_MAX_ITER, DEFAULT_MAXCHECK, DEFAULT_THRESHOLD
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Constructor Summary
Constructors Modifier Constructor Description protected
InterSatDirectViewDetector(OneAxisEllipsoid body, double skimmingAltitude, PVCoordinatesProvider secondary, AdaptableInterval maxCheck, double threshold, int maxIter, EventHandler handler)
Private constructor.InterSatDirectViewDetector(OneAxisEllipsoid body, PVCoordinatesProvider secondary)
simple constructor.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected InterSatDirectViewDetector
create(AdaptableInterval newMaxCheck, double newThreshold, int newMaxIter, EventHandler newHandler)
Build a new instance.double
g(SpacecraftState state)
Compute the value of the switching function.OneAxisEllipsoid
getCentralBody()
Get the central body.PVCoordinatesProvider
getSecondary()
Get the provider for the secondary satellite.double
getSkimmingAltitude()
Get the skimming altitude.InterSatDirectViewDetector
withSkimmingAltitude(double newSkimmingAltitude)
Setup the skimming altitude.-
Methods inherited from class org.orekit.propagation.events.AbstractDetector
create, getDetectionSettings, getHandler, getMaxCheckInterval, getMaxIterationCount, getThreshold, init, isForward, withDetectionSettings, withHandler, withMaxCheck, withMaxCheck, withMaxIter, withThreshold
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface org.orekit.propagation.events.EventDetector
finish
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Constructor Detail
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InterSatDirectViewDetector
public InterSatDirectViewDetector(OneAxisEllipsoid body, PVCoordinatesProvider secondary)
simple constructor.- Parameters:
body
- central bodysecondary
- provider for the secondary satellite
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InterSatDirectViewDetector
protected InterSatDirectViewDetector(OneAxisEllipsoid body, double skimmingAltitude, PVCoordinatesProvider secondary, AdaptableInterval maxCheck, double threshold, int maxIter, EventHandler handler)
Private constructor.- Parameters:
body
- central bodyskimmingAltitude
- skimming altitude at which events are triggeredsecondary
- provider for the secondary satellitemaxCheck
- maximum checking intervalthreshold
- convergence threshold (s)maxIter
- maximum number of iterations in the event time searchhandler
- event handler to call at event occurrences- Since:
- 12.0
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Method Detail
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getCentralBody
public OneAxisEllipsoid getCentralBody()
Get the central body.- Returns:
- central body
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getSkimmingAltitude
public double getSkimmingAltitude()
Get the skimming altitude.- Returns:
- skimming altitude at which events are triggered
- Since:
- 12.0
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getSecondary
public PVCoordinatesProvider getSecondary()
Get the provider for the secondary satellite.- Returns:
- provider for the secondary satellite
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create
protected InterSatDirectViewDetector create(AdaptableInterval newMaxCheck, double newThreshold, int newMaxIter, EventHandler newHandler)
Build a new instance.- Specified by:
create
in classAbstractDetector<InterSatDirectViewDetector>
- Parameters:
newMaxCheck
- maximum checking interval (s)newThreshold
- convergence threshold (s)newMaxIter
- maximum number of iterations in the event time searchnewHandler
- event handler to call at event occurrences- Returns:
- a new instance of the appropriate sub-type
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withSkimmingAltitude
public InterSatDirectViewDetector withSkimmingAltitude(double newSkimmingAltitude)
Setup the skimming altitude.The skimming altitude is the lowest altitude of the path between satellites at which events should be triggered. If set to 0.0, events are triggered exactly when the path passes just at central body limb.
- Parameters:
newSkimmingAltitude
- skimming altitude (m)- Returns:
- a new detector with updated configuration (the instance is not changed)
- Since:
- 12.0
- See Also:
getSkimmingAltitude()
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g
public double g(SpacecraftState state)
Compute the value of the switching function. This function must be continuous (at least in its roots neighborhood), as the integrator will need to find its roots to locate the events.The
g
function of this detector is the difference between the minimum altitude of intermediate points along the line of sight between satellites and theskimming altitude
. It is therefore positive when all intermediate points are above the skimming altitude, meaning satellites can see each other and it is negative when some intermediate points (which may be either endpoints) dive below this altitude, meaning satellites cannot see each other.- Parameters:
state
- the current state information: date, kinematics, attitude- Returns:
- value of the switching function
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