agi.foundation.propagators

(agi.foundation.models-2024r2.jar)

Class WalkerConstellation

java.lang.Object

agi.foundation.propagators.WalkerConstellation

public final class WalkerConstellation
extends Object

Supports the creation of Walker constellations of satellites.

Constructor Summary

Constructors

Constructor and Description
WalkerConstellation(WalkerConstellationPattern patternType, boolean phaseByMean, int numberOfPlanes, int numberOfSatellitesPerPlane, int slotOffset, ModifiedKeplerianElements seedElements) Creates a Walker constellation from the orbital elements of a seed satellite and other standard Walker constellation input parameters.

Method Summary

Modifier and Type	Method and Description
WalkerConstellationResult<J2Propagator>	createJ2Propagator(JulianDate orbitEpoch, ReferenceFrame referenceFrame, double j2UnnormalizedValue, double referenceDistance) Creates a nested collection of satellite propagators.
WalkerConstellationResult<J4Propagator>	createJ4Propagator(JulianDate orbitEpoch, ReferenceFrame referenceFrame, double j2UnnormalizedValue, double j4UnnormalizedValue, double referenceDistance) Creates a nested collection of satellite propagators.
WalkerConstellationResult<TwoBodyPropagator>	createTwoBodyPropagator(JulianDate orbitEpoch, ReferenceFrame referenceFrame) Creates a nested collection of satellite propagators.
int	getNumberOfPlanes() Gets the number of planes in the Walker constellation.
int	getNumberOfSatellitesPerPlane() Gets the number of satellites per plane of the Walker constellation.
WalkerConstellationPattern	getPatternType() Gets the pattern type of the Walker constellation.
boolean	getPhaseByMean() Gets a value indicating whether the mean anomaly or true anomaly is used to phase the Walker constellation.
ModifiedKeplerianElements	getSeedElements() Gets the ModifiedKeplerianElements of the seed satellite of the Walker constellation.
int	getSlotOffset() Gets the slot offset (interplane phasing) of the Walker constellation.
void	setNumberOfPlanes(int value) Sets the number of planes in the Walker constellation.
void	setNumberOfSatellitesPerPlane(int value) Sets the number of satellites per plane of the Walker constellation.
void	setPatternType(WalkerConstellationPattern value) Sets the pattern type of the Walker constellation.
void	setPhaseByMean(boolean value) Sets a value indicating whether the mean anomaly or true anomaly is used to phase the Walker constellation.
void	setSeedElements(ModifiedKeplerianElements value) Sets the ModifiedKeplerianElements of the seed satellite of the Walker constellation.
void	setSlotOffset(int value) Sets the slot offset (interplane phasing) of the Walker constellation.

Methods inherited from class java.lang.Object

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

Constructor Detail

WalkerConstellation

public WalkerConstellation(@Nonnull
                           WalkerConstellationPattern patternType,
                           boolean phaseByMean,
                           int numberOfPlanes,
                           int numberOfSatellitesPerPlane,
                           int slotOffset,
                           ModifiedKeplerianElements seedElements)

Creates a Walker constellation from the orbital elements of a seed satellite and other standard Walker constellation input parameters.

Parameters:

patternType - The Walker constellation has either a delta pattern or a star pattern.

phaseByMean - If true, then the satellites are distributed evenly by mean anomaly increments within each orbital plane. If false, then the satellites are distributed evenly by true anomaly increments within each orbital plane.

numberOfPlanes - The number of distinct orbital planes that the satellites are divided among.

numberOfSatellitesPerPlane - The number of satellites within each orbital plane.

slotOffset - Defines the interplane phasing of mean or true anomaly. The first satellite in each plane after the first has an anomaly value that is the seed satellite's anomaly value plus the slot offset times the number of preceding planes times 360 degrees divided by the total number of satellites in the entire constellation. The slot offset must be non-negative and less than the number of planes.

seedElements - Provides the ModifiedKeplerianElements of the seed satellite of the Walker constellation.

Method Detail

getPatternType

@Nonnull
public final WalkerConstellationPattern getPatternType()

Gets the pattern type of the Walker constellation.

setPatternType

public final void setPatternType(@Nonnull
                                 WalkerConstellationPattern value)

Sets the pattern type of the Walker constellation.

getPhaseByMean

public final boolean getPhaseByMean()

Gets a value indicating whether the mean anomaly or true anomaly is used to phase the Walker constellation.

setPhaseByMean

public final void setPhaseByMean(boolean value)

Sets a value indicating whether the mean anomaly or true anomaly is used to phase the Walker constellation.

getNumberOfPlanes

public final int getNumberOfPlanes()

Gets the number of planes in the Walker constellation.

setNumberOfPlanes

public final void setNumberOfPlanes(int value)

Sets the number of planes in the Walker constellation.

getNumberOfSatellitesPerPlane

public final int getNumberOfSatellitesPerPlane()

Gets the number of satellites per plane of the Walker constellation.

setNumberOfSatellitesPerPlane

public final void setNumberOfSatellitesPerPlane(int value)

Sets the number of satellites per plane of the Walker constellation.

getSlotOffset

public final int getSlotOffset()

Gets the slot offset (interplane phasing) of the Walker constellation.

setSlotOffset

public final void setSlotOffset(int value)

Sets the slot offset (interplane phasing) of the Walker constellation.

getSeedElements

public final ModifiedKeplerianElements getSeedElements()

Gets the ModifiedKeplerianElements of the seed satellite of the Walker constellation.

setSeedElements

public final void setSeedElements(ModifiedKeplerianElements value)

Sets the ModifiedKeplerianElements of the seed satellite of the Walker constellation.

createTwoBodyPropagator

public final WalkerConstellationResult<TwoBodyPropagator> createTwoBodyPropagator(@Nonnull
                                                                                  JulianDate orbitEpoch,
                                                                                  @Nonnull
                                                                                  ReferenceFrame referenceFrame)

Creates a nested collection of satellite propagators.

Parameters:

orbitEpoch - The orbit epoch of the created TwoBodyPropagator objects.

referenceFrame - The ReferenceFrame of the created TwoBodyPropagator objects.

Returns:

A WalkerConstellationResult that contains WalkerConstellationPlane objects for each plane that, in turn, contain TwoBodyPropagator objects for each satellite in each plane.

Throws:

ArgumentNullException - Thrown when the reference frame is null.

PropertyInvalidException - Thrown when the number of planes or the number of satellites per plane are not positive, the slot offset is less than zero or greater than or equal to the number of planes, or the seed satellite's eccentricity is less than zero or greater than or equal to one. (The seed satellite's eccentricity is greater than or equal to one when its inverse semi-major axis is zero or less.)

createJ2Propagator

public final WalkerConstellationResult<J2Propagator> createJ2Propagator(@Nonnull
                                                                        JulianDate orbitEpoch,
                                                                        ReferenceFrame referenceFrame,
                                                                        double j2UnnormalizedValue,
                                                                        double referenceDistance)

Creates a nested collection of satellite propagators.

Parameters:

orbitEpoch - The orbit epoch of the created J2Propagator objects.

referenceFrame - The ReferenceFrame of the created J2Propagator objects.

j2UnnormalizedValue - The non-normalized j2 parameter of the central body.

referenceDistance - A reference distance associated with the gravity field of the central body. (Usually, the equatorial radius of the central body.)

Returns:

A WalkerConstellationResult that contains WalkerConstellationPlane objects for each plane that, in turn, contain J2Propagator objects for each satellite in each plane.

Throws:

ArgumentNullException - Thrown when the reference frame is null.

PropertyInvalidException - Thrown when the number of planes or the number of satellites per plane are not positive, the slot offset is less than zero or greater than or equal to the number of planes, or the seed satellite's eccentricity is less than zero or greater than or equal to one. (The seed satellite's eccentricity is greater than or equal to one when its inverse semi-major axis is zero or less.)

createJ4Propagator

public final WalkerConstellationResult<J4Propagator> createJ4Propagator(@Nonnull
                                                                        JulianDate orbitEpoch,
                                                                        ReferenceFrame referenceFrame,
                                                                        double j2UnnormalizedValue,
                                                                        double j4UnnormalizedValue,
                                                                        double referenceDistance)

Creates a nested collection of satellite propagators.

Parameters:

orbitEpoch - The orbit epoch of the created J4Propagator objects.

referenceFrame - The ReferenceFrame of the created J4Propagator objects.

j2UnnormalizedValue - The non-normalized J2 parameter of the central body.

j4UnnormalizedValue - The non-normalized J4 parameter of the central body.

referenceDistance - A reference distance associated with the gravity field of the central body. (Usually, the equatorial radius of the central body.)

Returns:

A WalkerConstellationResult that contains WalkerConstellationPlane objects for each plane that, in turn, contain J4Propagator objects for each satellite in each plane.

Throws:

ArgumentNullException - Thrown when the reference frame is null.

PropertyInvalidException - Thrown when the number of planes or the number of satellites per plane are not positive, the slot offset is less than zero or greater than or equal to the number of planes, or the seed satellite's eccentricity is less than zero or greater than or equal to one. (The seed satellite's eccentricity is greater than or equal to one when its inverse semi-major axis is zero or less.)