BinaryOrbit Class Reference

Binary Orbit. More...

Inheritance diagram for BinaryOrbit:

Public Member Functions
void	Start ()
void	SetupOrbits ()
override bool	IsOnRails ()
	Check if body is configured at scene start to be fixed. (Allows objects to be optionally configured as not fixed, to allow e.g. Kepler eqn vs initial velocity in OrbitEllipse)
override void	PreEvolve (float physicalScale, float massScale)
	Called for each NBody object prior to evolution beginning. Allows a chance to setup internal state.
override void	Evolve (double physicsTime, GravityState gravityState, ref double[] r_new, ref double[] v_new, bool doCallbacks=true)
	In NBody mode, the center of mass NBody will run as a fixed object and determine it's new position each cycle. This ensures that it is up to date when used by OrbitPredictors to show the orbits of the binary pair.
double	MassForPredictor (NBody nbody)
	Determine the mass to set for an orbit predictor. May be called during OP Start() before Setup has been run, so needs to get nbody info to be safe.
override void	ApplyScale (float scale)
	Interface to apply the scale to the distance parameter of an orbit.
override void	ApplyXZChange ()
override void	InitNBody (float physicalScale, float massScale)
	Inits the N body. Called prior to evolution starting. Allows NBody object to adjust its position and velocity prior to evolution beginning.
override string	DumpInfo ()
	Create a string with info for display in GEConsole.
Public Member Functions inherited from OrbitUniversal
virtual void	InitNBody (float physicalScale, float massScale)
	Inits the N body. Called prior to evolution starting. Allows NBody object to adjust its position and velocity prior to evolution beginning.
void	InitFromActiveNBody (NBody activeNbody, NBody center, EvolveMode mode)
	Use an active NBody that is live in GE to initialize an orbit.
void	InitFromJplEphemeris (string data)
void	InitCOEFromTLEData ()
	Init the classical orbital element (COE) from Celestrak two-line element (TLE) information.
string	TLEStartEpoch ()
void	Init ()
void	Reset ()
	Reset the OrbitPredictor init mode.
void	SetMajorAxisInspector (double a)
	For ellipses can specify size using major-axis. Typically used by editor script, but may have other uses.
double	GetMajorAxisInspector ()
	Get the major axis for the orbit using the inspector value (world units).
double	GetMajorAxis ()
	Get the Major Axis is internal physical units. If the orbit is an ellipse the major axis is valid. If the orbit is a hyperbola, then the value of p will be negative and there is no major axis value.
double	GetApogeeInspector ()
	Get the apogee (point of greatest distance from focus) for the orbit in Scaled units (e.g. ORBITAL). This is typically used in the inspector prior to the game starting.
double	GetApogee ()
	Determine the orbit apogee (apoapsis) is internal physics units.
double	GetSemiParam ()
SGP4toGE	GetSGP4ToGE ()
double	GetEnergy ()
	Compute a real-time value for the orbital energy based on (r,v)
double	GetPerigeeInspector ()
	Get the perigee (point of closest approach to the focus) for the orbit in Scaled units (e.g. ORBITAL). This is typically used in the inspector prior to the game starting.
double	GetPerigee ()
	Determine the orbit preigee (periapsis) is internal physics units.
void	SetSizeWithApogeePerigee (double apogee, double perigee)
	Set the size and eccentricity of the ellipse by using values for apogee and perigee. (To be precise really should call them apoapsis and periapsis, but more people will know apogee/perigee).
void	SetSizeWithEccPerigee (double ecc, double perigee)
void	SetOrbitPredictor (bool flag)
delegate void	SGP4ErrorCallback (OrbitUniversal ou, int error)
	In SGP4 propagation the satellite can decay to the point where it should not be propagated. Users may wish to trigger a callback on this event. This allows for a callback to be registered.
void	AddSGP4ErrorCallback (SGP4ErrorCallback errorCallback)
	Callback for when an SGP4 satellite decays.
double	GetMu ()
void	SetMu (double mu)
	Set the mass of the orbit system. This is intended for use when OrbitU is not attached to an NBody e.g. in the case of a DustOrbit.
void	InitMu ()
	Init the value of mu from the nbody elements. Typically used by OrbitPredictor.
NBody	GetNBody ()
Vector3d	GetAxis ()
	Get the normal vector to the orbital plane (normalized).
void	InitFromOrbitData (OrbitData od, double time)
	Initialize the Orbit from orbital elements contained in an OrbitData object.
void	CopyFromOrbitUniversal (OrbitUniversal fromOrbit)
	Init from another OrbitUniversal.
void	InitFromRVT (Vector3d r, Vector3d v, double time, NBody center, bool relativePos, bool updateState=false)
	Initialize the orbit using position, velocity and time.
void	SetDejitterCOE (bool value)
void	ReInitForOrbitPredictor (Vector3d r, Vector3d v, double time)
	OrbitPredictor does not need to do a full re-init, just use RV to set new COE.
OrbitUtils.OrbitElements.TypeOrbit	PredictedOrbitType ()
	When this OrbitU is being used as an orbit predictor report the last type that was determined by the RVtoCOE.
void	InitFromSolarBody (SolarBody sbody)
	Inits from solar body. This will always be an ellipse.
OrbitUtils.OrbitElements	GetPKeplerCOE ()
virtual void	ApplyScale (float scale)
	Interface to apply the scale to the distance parameter of an orbit.
virtual void	ApplyXZChange ()
virtual bool	IsOnRails ()
	Check if body is configured at scene start to be fixed. (Allows objects to be optionally configured as not fixed, to allow e.g. Kepler eqn vs initial velocity in OrbitEllipse)
virtual void	PreEvolve (float physicalScale, float massScale)
	Called for each NBody object prior to evolution beginning. Allows a chance to setup internal state.
virtual void	Evolve (double physicsTime, GravityState gravityState, ref double[] r_new, ref double[] v_new, bool isQuery=false)
	Evolve the NBody. Implementating method uses physics time and scale to compute the new position, placing it in r. Velocity is also updated so that GetVelocity() can request it if it is of interest.
virtual void	EvolveSGP4 (double physicsTime, GravityState gravityState, double[] r_new, double[] v_new, bool isQuery=false)
	Evolve using the Simplified General Pertubation propagator model V4.
void	SetSGP4BlendTime (double time)
void	LockAtTime (double lockTime)
	Use in On-Rails mode to lock an object at a specific time. Any evolve calls will not re-compute the position/velocity but instead leave them unchanged.
void	UnlockTime ()
Vector3d	GetLockedPosVel ()
double	GetPeriod ()
double	GetAngularVelocity ()
double	GetStartTime ()
void	GetRVT (ref Vector3d r0, ref Vector3d v0, ref double time0)
	Get the intial conditions for the orbit. R0 and V0 are always relative to the center body. If the center is not at (0,0,0) and/or moving, need to adjust values outside.
bool	RVT_Equal (ref Vector3d r0, ref Vector3d v0, ref double time0, double tol)
	Utility function (used by e.g. OrbitPredictor) to see if the orbit initial conditions have changed. Used to determine when an OP needs to recompute the orbit in KEPLER mode.
void	GetRVTAbsolute (ref Vector3d r0, ref Vector3d v0, ref double time0)
void	GEUpdate (GravityEngine ge)
	Perform and update of the world game object position and velocity based on the internal state.
void	Move (Vector3 position)
	Move in response to a GE.MoveAll() call. (Not called from outside GE).
void	SetNBody (NBody nbody)
	Set the NBody that the orbit element will evolve. This is not commonly used, since the NBody is typically attached to the same game object as the FixedOrbit. The exception is when fixed orbit segments are part of a KeplerSequence (patched-conic evolution).
Vector3[]	OrbitPositions (int numPoints, Vector3 centerPos, bool doSceneMapping)
Vector3[]	OrbitPositions (int numPoints, Vector3 centerPos, bool doSceneMapping, float hyperRadius)
Vector3	PositionForPhase (float phaseDeg)
	Get the position for the specified phase in physics co-ordinates.
Vector3	VelocityForPhaseRelative (float phaseDeg)
Vector3	VelocityForPosition (Vector3 position)
	Given a position on the orbit (or a position that is used to establish a phase wrt the center) determine the velocity vector at that point on the orbit.
bool	CanApplyImpulse ()
NBody	GetCenterNBody ()
	Return the center NBody for the fixed orbit.
void	UpdatePositionAndVelocity (Vector3 pos, Vector3 vel)
	Set a new start position for orbit evolution with respect to the current center object.
void	SetNewCenter (NBody newCenter)
	Set a new center object. Used when doing Kepler ("on-rails") evolution and the object enters the sphere of influence of a new body. The inital conditions (r0,v0, t0) are updated to be with respect to the new center object allowing Kepler evolution wrt the new center.
void	ChangeEvolveMode (EvolveMode newMode)
	Change the evolve mode between KEPLER and GRAVITY_ENGINE. i.e. go from off-rails to on-rails.
Vector3	ApplyImpulse (Vector3 impulse)
	Apply an impulse to change the on-rails evolution (Kepler or SGP4). OrbitUniversal supports seamless changes from ellipse to parabola to hyperbola. This updates the initial conditions and start time (r0, v0, time0)
double	TimeOfFlight (Vector3d r0, Vector3d r1)
	Determine the time of flight in physics time units (GE internal time) that it takes for the body in orbit to go from relative position r0 to position r1.
double	TimeOfFlightEllipse (Vector3d r0, Vector3d r1)
	Find the time of flight from position r0 to r1 when the orbit is elliptical.
bool	IsCircular ()
Quaternion	GetConicOrientation ()
Vector3[]	HyperSegmentSymmetric (int numPoints, Vector3 centerPos, float radiusOrZero, bool doSceneMapping)
	Calculate points suitable for a line renderer that show a segment of the hyperbola for a specified radius with respect to the center.
Vector3[]	EllipseSegment (int numPoints, Vector3 centerPos, Vector3 pos, Vector3 destPoint, bool shortPath)
	Generate the points for an ellipse segment given the start and end positions. If shortPath then the short path between the points will be shown, otherwise the long way around.
Vector3[]	EllipseSegmentProRetro (int numPoints, Vector3 centerPos, Vector3 pos, Vector3 destPoint, bool retrograde)
	Generate the points for an ellipse segment given the start and end positions.
virtual string	DumpInfo ()
	Create a string with info for display in GEConsole.
Vector3	GetPositionForThetaRadians (float thetaRadians, Vector3 centerPos)
	Determine orbit position in physics space (with rotation and center offset) for the specified angle in the orbit (in radians)
Vector3d	GetPositionDForThetaRadians (double thetaRadians, bool relative)
	Determine orbit position in physics space (with rotation and center offset) for the specified angle in the orbit (in radians)
Vector3d	GetVelocityDForThetaRadians (double theta, bool relative)
Vector3[]	GetPositionsForRadius (double radius, Vector3 centerPos)
	Get the positions where the orbit is at a specified radius. In general there are two. The result is positions in world space. These can then be used in e.g. TimeOfFlight.
float	GetPhaseDegForRadius (double radius)
	Get the phase for the specified radius/altitude.
OrbitUtils.OrbitElements	GetCurrentOrbitalElements ()
	Get the current orbital elements using the live position and velocity from GE.
double	GetCurrentPhase ()
	Get the current phase (degrees) of the body based on the position and velocity retreived from GE.
Vector3[]	GetPositionsForRadius (double radius)
	Get the positions where the orbit is at a specified radius. In general there are two. The result is positions in world space. These can then be used in e.g. TimeOfFlight.
void	SetPositionDouble (Vector3d pos)
void	InitNBody (float physicalScale, float massScale)
	Inits the N body. Called prior to evolution starting. Allows NBody object to adjust its position and velocity prior to evolution beginning.
bool	IsOnRails ()
	Check if body is configured at scene start to be fixed. (Allows objects to be optionally configured as not fixed, to allow e.g. Kepler eqn vs initial velocity in OrbitEllipse)
void	PreEvolve (float physicalScale, float massScale)
	Called for each NBody object prior to evolution beginning. Allows a chance to setup internal state.
void	Evolve (double physicsTime, GravityState gravityState, ref double[] r, ref double[] v, bool isQuery=false)
	Evolve the NBody. Implementating method uses physics time and scale to compute the new position, placing it in r. Velocity is also updated so that GetVelocity() can request it if it is of interest.
void	GEUpdate (GravityEngine ge)
	Perform and update of the world game object position and velocity based on the internal state.
void	Move (Vector3 position)
	Handle dynamic origin shift.
void	SetNBody (NBody nbody)
	Set the NBody that the orbit element will evolve. This is not commonly used, since the NBody is typically attached to the same game object as the FixedOrbit. The exception is when fixed orbit segments are part of a KeplerSequence (patched-conic evolution).
Vector3	ApplyImpulse (Vector3 impulse)
	ApplyImpulse in Kepler mode. (Currently only OrbitUniversal does this)
NBody	GetCenterNBody ()
	Return the center NBody for the fixed orbit.
void	UpdatePositionAndVelocity (Vector3 pos, Vector3 vel)
	Update the position and velocity of the object in the orbit.
string	DumpInfo ()
	Create a string with info for display in GEConsole.
Vector3[]	OrbitPositions (int numPoints, Vector3 centerPos, bool doSceneMapping)
void	ApplyScale (float scale)
	Interface to apply the scale to the distance parameter of an orbit.
void	ApplyXZChange ()

Public Attributes
Vector3	initialPosition
	Velocity of center of mass of the binary pair.
Vector3	velocity
Public Attributes inherited from OrbitUniversal
EvolveMode	evolveMode
double	p = 10.0
double	p_inspector = 10.0
	Value of semi-parameter p from inspector (i.e. in GE selected units such as ORBITAL or SOLAR)
double	eccentricity
double	inclination
	inclinataion in degrees (0..180)
double	omega_uc
	Omega in degress (0..360)
double	omega_lc
	omega in degress (0..360)
double	phase = 0
	Phase in orbit in degrees.
double	sgp4_no
double	sgp4_bstar
double	pkepler_ndot = 0
double	pkepler_nddot = 0
NBody	centerNbody
	Object influencing this bodies motion.
InputMode	inputMode = InputMode.DOUBLE
string	jplEphemeris = ""
string	tleName = ""
string	tleLine1 =""
string	tleLine2 =""
bool	dejitterCOE = false
	Vector3d

Additional Inherited Members
Public Types inherited from OrbitUniversal
enum	EvolveMode { GRAVITY_ENGINE , KEPLERS_EQN , SGP4_PROPAGATOR , PKEPLER_J2 }
	Mode for evolution; NBody simulation in GE or "on-rails" using Kepler equation.
enum	InputMode {   DOUBLE , DOUBLE_ELLIPSE , ELLIPSE_MAJOR_AXIS_A , ELLIPSE_APOGEE_PERIGEE ,   ECC_PERIGEE , TWO_LINE_ELEMENT_SET }
Protected Member Functions inherited from OrbitUniversal
void	CalculateRotation ()
Protected Attributes inherited from OrbitUniversal
Quaternion	conic_orientation
GravityEngine	ge

Detailed Description

Binary Orbit.

Configures the initial velocities for two roughly equal masses to establish their elliptical orbits around the center of mass of the pair.

Must have two NBody objects with OrbitUniversal as immediate children.

The BinaryPair object can optionally have a zero-mass NBody and OrbitUniversal component attached. This will be used to determine the initial conditions for the binary pair (position and velocity) so the binary pair can be placed in orbit around another body. This "dummy" NBody is only used during the setup. (It will continue to evolve but there is no model attached and nothing in the scene will be affected by its zero mass.)

Member Function Documentation

ApplyScale()

override void BinaryOrbit.ApplyScale

(

float

scale

)

Interface to apply the scale to the distance parameter of an orbit.

Parameters

scale

Scale.

Implements IOrbitScalable.

ApplyXZChange()

override void BinaryOrbit.ApplyXZChange

(

)

Implements IOrbitScalable.

DumpInfo()

override string BinaryOrbit.DumpInfo ( )

virtual

Create a string with info for display in GEConsole.

Returns

Reimplemented from OrbitUniversal.

Evolve()

override void BinaryOrbit.Evolve ( double  physicsTime, GravityState  gravityState, ref double[]  r_new, ref double[]  v_new, bool  doCallbacks = true  )

virtual

In NBody mode, the center of mass NBody will run as a fixed object and determine it's new position each cycle. This ensures that it is up to date when used by OrbitPredictors to show the orbits of the binary pair.

If the CM has an OrbitUniversal attached, then it will let that OU move the CM.

Parameters

physicsTime
gravityState
r_new
v_new

Reimplemented from OrbitUniversal.

InitNBody()

override void BinaryOrbit.InitNBody ( float  physicalScale, float  massScale  )

virtual

Inits the N body. Called prior to evolution starting. Allows NBody object to adjust its position and velocity prior to evolution beginning.

Parameters

physicalScale

Physical scale.

Reimplemented from OrbitUniversal.

IsOnRails()

override bool BinaryOrbit.IsOnRails ( )

virtual

Check if body is configured at scene start to be fixed. (Allows objects to be optionally configured as not fixed, to allow e.g. Kepler eqn vs initial velocity in OrbitEllipse)

Returns

true if this instance is fixed; otherwise, false.

Reimplemented from OrbitUniversal.

MassForPredictor()

double BinaryOrbit.MassForPredictor

(

NBody

nbody

)

Determine the mass to set for an orbit predictor. May be called during OP Start() before Setup has been run, so needs to get nbody info to be safe.

Parameters

nbody

Returns

PreEvolve()

override void BinaryOrbit.PreEvolve ( float  physicalScale, float  massScale  )

virtual

Called for each NBody object prior to evolution beginning. Allows a chance to setup internal state.

Parameters

physicalScale	Physical scale.
massScale	Mass scale.

Reimplemented from OrbitUniversal.

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The documentation for this class was generated from the following file:

• C:/Users/musgr/Documents/Unity/gravityengine/Assets/GravityEngine/Scripts/Orbits/BinaryOrbit.cs