O_SESSAME Namespace Reference

Detailed Description

Warning:: NOT VERIFIED

Todo:: Add test cases

Compounds

class Attitude

Class encapsulating the rotational attitude of a rigid body frame with respect to another frame. More...

class AttitudeState

class ASCIIConverter

Class for importing and exporting data to ASCII. More...

class AttitudeHistory

Class for storing a time history of attitude states. More...

class BinaryConverter

Class for importing and exporting data to ASCII. More...

class Command

Class interface for creating commands in Open-SESSAME. More...

class SimpleCommand

Interface for creating simple, templated commands in Open-SESSAME. More...

class ConversionForm

Class interface for importing and exporting data to various external formats. More...

class Converter

Class interface for importing and exporting data to various external formats. More...

class History

Base class for histories storing state variables, also stores time states. More...

class MatlabExporter

Class for exporting data to MatLab. More...

class MatrixConversionForm

Class interface for importing and exporting data to various external formats. More...

class OrbitHistory

Class for storing a time history of orbital states. More...

class Spacecraft

class AnalyticPropagator

Encapsulation of the propagation of the spacecraft dynamics (attitude, orbital, etc.). More...

class AttitudeNumericPropagator

class CombinedNumericPropagator

class NumericPropagator

class Propagator

Encapsulation of the propagation of the spacecraft dynamics (attitude, orbital, etc.). More...

class CentralBody

Abstract representation of a central body. More...

class EarthCentralBody

struct MagneticFieldCoefficients

Structure to hold typical magnetic model coefficients. More...

class MagneticModel

The MagneticModel class encapsulates a magnetic model of a central body. More...

class TiltedDipoleMagneticModel

Define the model of a magnetic field using a tilted dipole model. More...

class EnvFunction

class Environment

Encapsulation of a spacecraft environment (disturbance forces, torques, central body, etc.). More...

class Orbit

class OrbitState

Encapsulation of an Orbit State, including its coordinate type and reference frame. More...

struct tleStruct

class Keplerian

Keplerian orbital element representation of the orbital position. More...

class OrbitStateRepresentation

Abstract base type of the orbit state representation. More...

class PositionVelocity

Position & Velocity representation of the orbital position. More...

class DirectionCosineMatrix

3x3 direction cosine matrix attitude representation. More...

class ModifiedRodriguezParameters

3x1 Modified Rodriguez Parameters attitude representation. More...

class Quaternion

The non-singular, redundant Euler parameter (quaternion) vector. More...

class Rotation

A generalized rotation class to represent any attitude coordinate transformation. More...

class Functor

Abstract class to hold the pointer to an force calculating functor. More...

class SpecificFunctor

derived template class More...

class ObjectFunctor

derived template class More...

class Integrator

Interface class to the Integrator algorithm strategies. More...

class Interpolator

Abstract interface to the set of interpolators. More...

class LinearInterpolator

Interpolates between a given set of data points to create a linear functional approximation. More...

class NaturalCubicSplineInterpolator

Interpolates between a given set of data points to create a smooth function. More...

class Plot

A Plot object is used to display data in a 2-D or 3-D plot. More...

class RungeKuttaFehlbergIntegrator

Runge-Kutta-Fehlberg integrator. More...

class RungeKuttaIntegrator

Implementation of a Runge-Kutta (Fourth Order) Integrator. More...

class ssfTime

Simulation Time object. More...

Typedefs

typedef void(* IntegratedAttitudeStateConversionFunction )(const Matrix &_meshPoint, AttitudeState &_convertedAttitudeState)

Defined function pointer to integrated attitude state conversion function.

typedef int AttitudeFrame

typedef vector< void * > EnvFuncParamaterType

typedef Vector(* pt2EnvFunc )(const ssfTime &_currentTime, const OrbitState &_currentOrbitState, const AttitudeState &_currentAttitudeState, const EnvFuncParamaterType &_parameterList)

typedef CAMdoubleMatrix Matrix

typedef CAMdoubleVector Vector

typedef void(* IntegratedOrbitStateConversionFunction )(const Matrix &_meshPoint, OrbitState &_convertedOrbitState)

Defined function pointer to integrated orbital state conversion function.

typedef Vector(* vectorFuncPtr )(const Vector &_vectorFuncPtrParams)

A generalized pointer to a function that takes a vector as a parameter and returns a vector.

typedef Vector(* odeFunc )(const double &_time, const Vector &_state, const Matrix &_parameters, vectorFuncPtr _funcPtr)

defines a pointer to an integrator's right-hand side (RHS) function

typedef Vector(* odeFunctor )(const ssfTime &_time, const Vector &_integratingState, Orbit *_pOrbit, Attitude *_pAttitude, const Matrix &_parameters, const Functor &_forceFunctorPtr)

defines a pointer to an integrator's right-hand side (RHS) function using a functor for the arbitrary vector function

typedef double Angle

Representation of an angle in radians. Currently the angle representation is assumed to be radians, and can be used in any of the other Trigonometry functions to convert to Degrees or Degrees-Minutes-Seconds. In the future, the Angle should be a class that is unit independent and include the appropriate conversion functions.

typedef double ssfSeconds

typedef double ssfJulianDate

Enumerations

enum RotationType {
DCM_Type, EulerAngle_Type, EulerAxisAngle_Type, MRP_Type,
Quaternion_Type
}

Various representations of a rotation. More...

enum RotationSense { LEFT_HAND = -1, RIGHT_HAND = 1 }

The Sense, or "handedness" of a rotation system. More...

Functions

Matrix eye (int _rowColumns)

Creates an square identity matrix of specified size.

double trace (const Matrix &_inMatrix)

Calculates the trace of matrix (sum of elements along diagonal).

double norm2 (const Vector &_inVector)

Calculates the 2-norm of the vector (square-root of the sum of the squares).

void normalize (Vector &_inVector)

Normalizes a vector.

double normInf (const Vector &_inVector)

Calculates the Infinity-norm of the vector (largest value of the components).

Matrix skew (const Vector &_inVector)

Calculates the skew-symmetric matrix of a vector.

Vector crossP (const Vector &_v1, const Vector &_v2)

Calculates the cross product of 2 vectors.

DirectionCosineMatrix R1 (const Angle &_Angle)

Calculates the principal rotation of the angle about the 1-axis. DirectionCosineMatrix.

DirectionCosineMatrix R2 (const Angle &_Angle)

Calculates the principal rotation of the angle about the 2-axis. DirectionCosineMatrix.

DirectionCosineMatrix R3 (const Angle &_Angle)

Calculates the principal rotation of the angle about the 3-axis. DirectionCosineMatrix.

double DMS2Deg (const double &_Degrees, const double &_Minutes, const double &_Seconds)

Converts an angle from Degrees, Minutes, Seconds (^o,','') to a single quantity in degrees and fractions of a degree.

void Deg2DMS (const double &_Angle, double &Degrees, double &Minutes, double &Seconds)

Converts an angle from a single quantity in degrees and fractions of a degree to Degrees, Minutes, Seconds (^o,','').

Angle DMS2Rad (const double &_Degrees, const double &_Minutes, const double &_Seconds)

Converts an angle from Degrees, Minutes, Seconds (^o,','') to radians.

Angle Deg2Rad (const Angle &_Degrees)

Converts an angle from Degrees to radians.

void Rad2DMS (const Angle &_Radians, double &Degrees, double &Minutes, double &Seconds)

Converts an angle from radians to degrees, minutes, second format.

Angle Rad2Deg (const Angle &_Radians)

Converts an angle from radians to degrees.

Angle atanh (const double &_z)

void Plot2D (const Matrix &_data)

Use GnuPlot to plot the data in a matrix.

void Plot3D (const Matrix &_data)

void DayofYear2YMD (int _dayOfYear, int _year, int &_month, int &_day)

ostream & operator<< (ostream &s, ssfTime &t)

ssfTime tockTime (-1)

void tick ()

Variables

const double GRAVITATIONAL_CONSTANT = 6.669 * pow(10.0,-11.0)

const double deg2rad = (float)PI / 180.0

const int MatrixIndexBase = 1

const int VectorIndexBase = 1

const int MatrixRowsIndex = 1

const int MatrixColsIndex = 2

const int SEMIMAJOR_AXIS = VectorIndexBase + 0

const int ECCENTRICITY = VectorIndexBase + 1

const int INCLINATION = VectorIndexBase + 2

const int LONG_ASC_NODE = VectorIndexBase + 3

const int ARG_PERIGEE = VectorIndexBase + 4

const int TRUE_ANOMALY = VectorIndexBase + 5

const int QUATERNION_SIZE = 4

Number of elements in a quaternion vector.

const int MRP_SIZE = 3

Number of elements in a MRP vector.

const int DCM_SIZE = 3

Number of elements in a DCM row or column.

const int EULERAXIS_SIZE = 3

Number of elements in an euler axis.

const int EULERANGLES_SIZE = 3

Number of elements in an euler angle sequence.

int DaysInMonth [12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}

const ssfTime c_GreenwichSiderealEpochTime = ssfTime(1970,1,1,0,0,0)

time used as epoch for measuring Greenwich sidereal time.

const Angle c_GreenwichSiderealTimeAtEpoch = 1.74933340

Typedef Documentation

typedef int O_SESSAME::AttitudeFrame

Definition at line 20 of file AttitudeState.h.

typedef vector<void*> O_SESSAME::EnvFuncParamaterType

specification of the parameter list type to be used for environmental function pointers
Definition at line 45 of file Environment.h.

typedef Vector(* O_SESSAME::pt2EnvFunc)(const ssfTime &_currentTime, const OrbitState &_currentOrbitState, const AttitudeState &_currentAttitudeState, const EnvFuncParamaterType &_parameterList)

defines a pointer to a Environmental disturbance calculating function
Definition at line 47 of file Environment.h.

typedef CAMdoubleMatrix O_SESSAME::Matrix

< Encapsulation of CAMdoubleMatrix class
Definition at line 24 of file Matrix.h.

typedef CAMdoubleVector O_SESSAME::Vector

< Encapsulation of CAMdoubleVector class
Definition at line 25 of file Matrix.h.

Function Documentation

Matrix eye ( int _rowColumns )

Creates an square identity matrix of specified size.

Parameters:

_rowColumns Number of rows and columns to size matrix (will be a square matrix).

Todo:
Implement eye as part of Vector or CAMdoubleVector class

Definition at line 31 of file Matrix.h.

double trace ( const Matrix & _inMatrix )

Calculates the trace of matrix (sum of elements along diagonal).

Parameters:

_inMatrix Matrix to have trace calculated.

Todo:
Implement trace as part of Vector or CAMdoubleVector class

Definition at line 44 of file Matrix.h.

double norm2 ( const Vector & _inVector )

Calculates the 2-norm of the vector (square-root of the sum of the squares).

Todo:
Implement norm2 as part of Vector or CAMdoubleVector class

Parameters:

_inVector Vector to calculate the 2-norm of.

Returns:
Square-root of the sum of squares of elements in vector.

Definition at line 57 of file Matrix.h.

void normalize ( Vector & _inVector )

Normalizes a vector.

Parameters:

_inVector Vector to be normalized.

Todo:
Implement normalize as part of Vector or CAMdoubleVector class

Definition at line 69 of file Matrix.h.

double normInf ( const Vector & _inVector )

Calculates the Infinity-norm of the vector (largest value of the components).

Parameters:

_inVector Vector to calculate the 2-norm of.

Returns:
Absolute value of maximum component in vector.

Todo:
Implement normInf as part of Vector or CAMdoubleVector class

Definition at line 80 of file Matrix.h.

Matrix skew ( const Vector & _inVector )

Calculates the skew-symmetric matrix of a vector.
Equation: /f[ {v^{}} = {bmatrix} 0 & -v_3 & v_2\ v_3 & 0 & -v_1\ -v_2 & v_1 & 0 {bmatrix} /f]
Parameters:

_inVector Vector to calculate the skew-symmetric matrix of.

Returns:
Skew-symmetric matrix (3x3).

Todo:
Implement skew as part of Vector or CAMdoubleVector class

Definition at line 99 of file Matrix.h.

Vector crossP ( const Vector & _v1,

const Vector & _v2

)

Calculates the cross product of 2 vectors.
Equation: /f$ v_3 = v_1 v_2 = v_1/f$
Parameters:

_inVector Vector to calculate the 2-norm of.

Returns:
Cross product of 2 vectors.

Todo:
Implement crossP as part of Vector or CAMdoubleVector class

Definition at line 124 of file Matrix.h.

void Plot2D ( const Matrix & _data ) [static]

Use GnuPlot to plot the data in a matrix.

Parameters:

_data Matrix of data, the first column is x, and each of the other columns will be plotted on the y-axis

Definition at line 51 of file Plot.h.

void Plot3D ( const Matrix & _data ) [static]

Definition at line 78 of file Plot.h.

void DayofYear2YMD ( int _dayOfYear,

int _year,

int & _month,

int & _day

)

Definition at line 45 of file Time.cpp.

ostream& operator<< ( ostream & s,

ssfTime & t

)

Definition at line 149 of file Time.cpp.

ssfTime tockTime ( - 1 ) [static]

void tick ( )

Definition at line 428 of file Time.h.

Variable Documentation

const double O_SESSAME::GRAVITATIONAL_CONSTANT = 6.669 * pow(10.0,-11.0)

Earth Radius [/f$m^3/kg-s^2/f$]
Definition at line 24 of file EarthCentralBody.h.

const double O_SESSAME::deg2rad = (float)PI / 180.0

Earth Radius [-]
Definition at line 26 of file EarthCentralBody.h.

const int O_SESSAME::MatrixIndexBase = 1

< Beginning index of Matrix class
Definition at line 20 of file Matrix.h.

const int O_SESSAME::VectorIndexBase = 1

< Beginning index of Vector class
Definition at line 21 of file Matrix.h.

const int O_SESSAME::MatrixRowsIndex = 1

< Value referring to the "rows" index
Definition at line 22 of file Matrix.h.

const int O_SESSAME::MatrixColsIndex = 2

< Value referring to the "columns" index
Definition at line 23 of file Matrix.h.

const int O_SESSAME::SEMIMAJOR_AXIS = VectorIndexBase + 0

position of the Semimajor axis, , in the element vector
Definition at line 31 of file Keplerian.h.

const int O_SESSAME::ECCENTRICITY = VectorIndexBase + 1

position of the eccentricity, , in the element vector
Definition at line 32 of file Keplerian.h.

const int O_SESSAME::INCLINATION = VectorIndexBase + 2

position of the inclination, , in the element vector
Definition at line 33 of file Keplerian.h.

const int O_SESSAME::LONG_ASC_NODE = VectorIndexBase + 3

position of the longitude of the ascending node, , in the element vector
Definition at line 34 of file Keplerian.h.

const int O_SESSAME::ARG_PERIGEE = VectorIndexBase + 4

position of the argument of perigee, , in the element vector
Definition at line 35 of file Keplerian.h.

const int O_SESSAME::TRUE_ANOMALY = VectorIndexBase + 5

position of the true anomaly, , in the element vector
Definition at line 36 of file Keplerian.h.

int O_SESSAME::DaysInMonth[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31} [static]

Definition at line 16 of file Time.cpp.

const ssfTime O_SESSAME::c_GreenwichSiderealEpochTime = ssfTime(1970,1,1,0,0,0) [static]

time used as epoch for measuring Greenwich sidereal time.

Definition at line 394 of file Time.h.

const Angle O_SESSAME::c_GreenwichSiderealTimeAtEpoch = 1.74933340 [static]

actual Greenwich sidereal time at the specified epoch, m_GreenwichSiderealEpochTime.
Definition at line 396 of file Time.h.

Generated on Wed Aug 6 12:59:12 2003 for Open-Sessame Framework by

1.3


Compounds
class	Attitude
	Class encapsulating the rotational attitude of a rigid body frame with respect to another frame. More...
class	AttitudeState
class	ASCIIConverter
	Class for importing and exporting data to ASCII. More...
class	AttitudeHistory
	Class for storing a time history of attitude states. More...
class	BinaryConverter
	Class for importing and exporting data to ASCII. More...
class	Command
	Class interface for creating commands in Open-SESSAME. More...
class	SimpleCommand
	Interface for creating simple, templated commands in Open-SESSAME. More...
class	ConversionForm
	Class interface for importing and exporting data to various external formats. More...
class	Converter
	Class interface for importing and exporting data to various external formats. More...
class	History
	Base class for histories storing state variables, also stores time states. More...
class	MatlabExporter
	Class for exporting data to MatLab. More...
class	MatrixConversionForm
	Class interface for importing and exporting data to various external formats. More...
class	OrbitHistory
	Class for storing a time history of orbital states. More...
class	Spacecraft
class	AnalyticPropagator
	Encapsulation of the propagation of the spacecraft dynamics (attitude, orbital, etc.). More...
class	AttitudeNumericPropagator
class	CombinedNumericPropagator
class	NumericPropagator
class	Propagator
	Encapsulation of the propagation of the spacecraft dynamics (attitude, orbital, etc.). More...
class	CentralBody
	Abstract representation of a central body. More...
class	EarthCentralBody
struct	MagneticFieldCoefficients
	Structure to hold typical magnetic model coefficients. More...
class	MagneticModel
	The MagneticModel class encapsulates a magnetic model of a central body. More...
class	TiltedDipoleMagneticModel
	Define the model of a magnetic field using a tilted dipole model. More...
class	EnvFunction
class	Environment
	Encapsulation of a spacecraft environment (disturbance forces, torques, central body, etc.). More...
class	Orbit
class	OrbitState
	Encapsulation of an Orbit State, including its coordinate type and reference frame. More...
struct	tleStruct
class	Keplerian
	Keplerian orbital element representation of the orbital position. More...
class	OrbitStateRepresentation
	Abstract base type of the orbit state representation. More...
class	PositionVelocity
	Position & Velocity representation of the orbital position. More...
class	DirectionCosineMatrix
	3x3 direction cosine matrix attitude representation. More...
class	ModifiedRodriguezParameters
	3x1 Modified Rodriguez Parameters attitude representation. More...
class	Quaternion
	The non-singular, redundant Euler parameter (quaternion) vector. More...
class	Rotation
	A generalized rotation class to represent any attitude coordinate transformation. More...
class	Functor
	Abstract class to hold the pointer to an force calculating functor. More...
class	SpecificFunctor
	derived template class More...
class	ObjectFunctor
	derived template class More...
class	Integrator
	Interface class to the Integrator algorithm strategies. More...
class	Interpolator
	Abstract interface to the set of interpolators. More...
class	LinearInterpolator
	Interpolates between a given set of data points to create a linear functional approximation. More...
class	NaturalCubicSplineInterpolator
	Interpolates between a given set of data points to create a smooth function. More...
class	Plot
	A Plot object is used to display data in a 2-D or 3-D plot. More...
class	RungeKuttaFehlbergIntegrator
	Runge-Kutta-Fehlberg integrator. More...
class	RungeKuttaIntegrator
	Implementation of a Runge-Kutta (Fourth Order) Integrator. More...
class	ssfTime
	Simulation Time object. More...
Typedefs
typedef void(*	IntegratedAttitudeStateConversionFunction )(const Matrix &_meshPoint, AttitudeState &_convertedAttitudeState)
	Defined function pointer to integrated attitude state conversion function.
typedef int	AttitudeFrame
typedef vector< void * >	EnvFuncParamaterType
typedef Vector(*	pt2EnvFunc )(const ssfTime &_currentTime, const OrbitState &_currentOrbitState, const AttitudeState &_currentAttitudeState, const EnvFuncParamaterType &_parameterList)
typedef CAMdoubleMatrix	Matrix
typedef CAMdoubleVector	Vector
typedef void(*	IntegratedOrbitStateConversionFunction )(const Matrix &_meshPoint, OrbitState &_convertedOrbitState)
	Defined function pointer to integrated orbital state conversion function.
typedef Vector(*	vectorFuncPtr )(const Vector &_vectorFuncPtrParams)
	A generalized pointer to a function that takes a vector as a parameter and returns a vector.
typedef Vector(*	odeFunc )(const double &_time, const Vector &_state, const Matrix &_parameters, vectorFuncPtr _funcPtr)
	defines a pointer to an integrator's right-hand side (RHS) function
typedef Vector(*	odeFunctor )(const ssfTime &_time, const Vector &_integratingState, Orbit _pOrbit, Attitude _pAttitude, const Matrix &_parameters, const Functor &_forceFunctorPtr)
	defines a pointer to an integrator's right-hand side (RHS) function using a functor for the arbitrary vector function
typedef double	Angle
	Representation of an angle in radians. Currently the angle representation is assumed to be radians, and can be used in any of the other Trigonometry functions to convert to Degrees or Degrees-Minutes-Seconds. In the future, the Angle should be a class that is unit independent and include the appropriate conversion functions.
typedef double	ssfSeconds
typedef double	ssfJulianDate
Enumerations
enum	RotationType { DCM_Type, EulerAngle_Type, EulerAxisAngle_Type, MRP_Type, Quaternion_Type }
	Various representations of a rotation. More...
enum	RotationSense { LEFT_HAND = -1, RIGHT_HAND = 1 }
	The Sense, or "handedness" of a rotation system. More...
Functions
Matrix	eye (int _rowColumns)
	Creates an square identity matrix of specified size.
double	trace (const Matrix &_inMatrix)
	Calculates the trace of matrix (sum of elements along diagonal).
double	norm2 (const Vector &_inVector)
	Calculates the 2-norm of the vector (square-root of the sum of the squares).
void	normalize (Vector &_inVector)
	Normalizes a vector.
double	normInf (const Vector &_inVector)
	Calculates the Infinity-norm of the vector (largest value of the components).
Matrix	skew (const Vector &_inVector)
	Calculates the skew-symmetric matrix of a vector.
Vector	crossP (const Vector &_v1, const Vector &_v2)
	Calculates the cross product of 2 vectors.
DirectionCosineMatrix	R1 (const Angle &_Angle)
	Calculates the principal rotation of the angle about the 1-axis. DirectionCosineMatrix.
DirectionCosineMatrix	R2 (const Angle &_Angle)
	Calculates the principal rotation of the angle about the 2-axis. DirectionCosineMatrix.
DirectionCosineMatrix	R3 (const Angle &_Angle)
	Calculates the principal rotation of the angle about the 3-axis. DirectionCosineMatrix.
double	DMS2Deg (const double &_Degrees, const double &_Minutes, const double &_Seconds)
	Converts an angle from Degrees, Minutes, Seconds (^o,','') to a single quantity in degrees and fractions of a degree.
void	Deg2DMS (const double &_Angle, double &Degrees, double &Minutes, double &Seconds)
	Converts an angle from a single quantity in degrees and fractions of a degree to Degrees, Minutes, Seconds (^o,','').
Angle	DMS2Rad (const double &_Degrees, const double &_Minutes, const double &_Seconds)
	Converts an angle from Degrees, Minutes, Seconds (^o,','') to radians.
Angle	Deg2Rad (const Angle &_Degrees)
	Converts an angle from Degrees to radians.
void	Rad2DMS (const Angle &_Radians, double &Degrees, double &Minutes, double &Seconds)
	Converts an angle from radians to degrees, minutes, second format.
Angle	Rad2Deg (const Angle &_Radians)
	Converts an angle from radians to degrees.
Angle	atanh (const double &_z)
void	Plot2D (const Matrix &_data)
	Use GnuPlot to plot the data in a matrix.
void	Plot3D (const Matrix &_data)
void	DayofYear2YMD (int _dayOfYear, int _year, int &_month, int &_day)
ostream &	operator<< (ostream &s, ssfTime &t)
ssfTime	tockTime (-1)
void	tick ()
Variables
const double	GRAVITATIONAL_CONSTANT = 6.669 * pow(10.0,-11.0)
const double	deg2rad = (float)PI / 180.0
const int	MatrixIndexBase = 1
const int	VectorIndexBase = 1
const int	MatrixRowsIndex = 1
const int	MatrixColsIndex = 2
const int	SEMIMAJOR_AXIS = VectorIndexBase + 0
const int	ECCENTRICITY = VectorIndexBase + 1
const int	INCLINATION = VectorIndexBase + 2
const int	LONG_ASC_NODE = VectorIndexBase + 3
const int	ARG_PERIGEE = VectorIndexBase + 4
const int	TRUE_ANOMALY = VectorIndexBase + 5
const int	QUATERNION_SIZE = 4
	Number of elements in a quaternion vector.
const int	MRP_SIZE = 3
	Number of elements in a MRP vector.
const int	DCM_SIZE = 3
	Number of elements in a DCM row or column.
const int	EULERAXIS_SIZE = 3
	Number of elements in an euler axis.
const int	EULERANGLES_SIZE = 3
	Number of elements in an euler angle sequence.
int	DaysInMonth [12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
const ssfTime	c_GreenwichSiderealEpochTime = ssfTime(1970,1,1,0,0,0)
	time used as epoch for measuring Greenwich sidereal time.
const Angle	c_GreenwichSiderealTimeAtEpoch = 1.74933340