Package org.orekit.orbits

Class WalkerConstellation

java.lang.Object

org.orekit.orbits.WalkerConstellation

public class WalkerConstellation
extends Object

Builder for orbits of satellites forming a Walker constellation.

It manages the 2 patterns:

• Delta, with ascending nodes distributed over 360°
• Star, with ascending nodes distributed over 180°

Since:

12.1

Author:

Luc Maisonobe

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	WalkerConstellation.Pattern	Enumerate for Walker constellation design patterns.

Constructor Summary

Constructors

Constructor	Description
WalkerConstellation(int t, int p, int f)	Default constructor for Walker Delta constellation.
WalkerConstellation(int t, int p, int f, WalkerConstellation.Pattern pattern)	Complete constructor with the choice of the pattern.

Method Summary

Modifier and Type	Method	Description
<O extends Orbit> WalkerConstellationSlot<O>	buildReferenceSlot(O referenceOrbit)	Create the reference slot, which is satellite 0 in plane 0.
<O extends Orbit> List<List<WalkerConstellationSlot<O>>>	buildRegularSlots(O referenceOrbit)	Create the regular slots.
<O extends Orbit> WalkerConstellationSlot<O>	buildSlot(WalkerConstellationSlot<O> existingSlot, int plane, double satellite)	Create one offset slot from an already existing slot.
int	getF()	Get the phasing parameter.
int	getP()	Get the number of orbital planes.
WalkerConstellation.Pattern	getPattern()	Get the constellation pattern.
int	getT()	Get the total number of satellites.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

WalkerConstellation

public WalkerConstellation(int t,
 int p,
 int f)

Default constructor for Walker Delta constellation.

Parameters:

t - total number of satellites

p - number of orbital planes

f - phasing parameter

WalkerConstellation

public WalkerConstellation(int t,
 int p,
 int f,
 WalkerConstellation.Pattern pattern)

Complete constructor with the choice of the pattern.

Parameters:

t - total number of satellites

p - number of orbital planes

f - phasing parameter

pattern - constellation pattern

Method Details

getT

public int getT()

Get the total number of satellites.

Returns:

total number of satellites

getP

public int getP()

Get the number of orbital planes.

Returns:

number of orbital planes

getF

public int getF()

Get the phasing parameter.

Returns:

phasing parameter

getPattern

public WalkerConstellation.Pattern getPattern()

Get the constellation pattern.

Returns:

constellation pattern

buildRegularSlots

public <O extends Orbit>
List<List<WalkerConstellationSlot<O>>> buildRegularSlots(O referenceOrbit)

Create the regular slots.

This method builds the T regular satellite, with integer satellite indices. If additional in-orbit spare satellites must be created, the buildSlot method must be called explicitly.

The various orbits are built from the referenceOrbit using plane rotations and shifts. This implies that if orbit does not include non-Keplerian derivatives, a simple Keplerian motion is assumed, which is the intended use case.

Type Parameters:

O - type of the orbits

Parameters:

referenceOrbit - orbit of the reference satellite, in plane 0 and at WalkerConstellationSlot.getSatellite() satellite index} 0

Returns:

built orbits as a list of list, organized by planes

See Also:

• buildReferenceSlot(Orbit)
• buildSlot(WalkerConstellationSlot, int, double)

buildReferenceSlot

public <O extends Orbit> WalkerConstellationSlot<O> buildReferenceSlot(O referenceOrbit)

Create the reference slot, which is satellite 0 in plane 0.

Type Parameters:

O - type of the orbits

Parameters:

referenceOrbit - orbit of the reference satellite, in plane 0 and at WalkerConstellationSlot.getSatellite() satellite index} 0

Returns:

build reference slot

See Also:

• buildRegularSlots(Orbit)
• buildSlot(WalkerConstellationSlot, int, double)

buildSlot

public <O extends Orbit> WalkerConstellationSlot<O> buildSlot(WalkerConstellationSlot<O> existingSlot,
 int plane,
 double satellite)

Create one offset slot from an already existing slot.

Type Parameters:

O - type of the orbits

Parameters:

existingSlot - existing slot (may be the reference slot or not)

plane - plane index of the new slot (may be non-integer for in-orbit spare satellites)

satellite - new slot satellite index in plane (may be non-integer if needed)

Returns:

built slot

See Also:

• buildRegularSlots(Orbit)
• buildReferenceSlot(Orbit)