Detailed Description

Models the EOM and integration/propagation of state.

The Equations of Motion (EOM) for JSBSim are integrated to propagate the state of the vehicle given the forces and moments that act on it. The integration accounts for a rotating Earth.

Integration of rotational and translation position and rate can be customized as needed or frozen by the selection of no integrator. The selection of which integrator to use is done through the setting of the associated property. There are four properties which can be set:

simulation/integrator/rate/rotational
simulation/integrator/rate/translational
simulation/integrator/position/rotational
simulation/integrator/position/translational

Each of the integrators listed above can be set to one of the following values:

No integrator (Freeze)
Rectangular Euler
Trapezoidal
Adams Bashforth 2
Adams Bashforth 3
Adams Bashforth 4

Author: Jon S. Berndt, Mathias Froehlich, Bertrand Coconnier

Definition at line 93 of file FGPropagate.h.

#include <FGPropagate.h>

Inheritance diagram for FGPropagate:

Collaboration diagram for FGPropagate:

Classes
struct	Inputs

struct	VehicleState
	The current vehicle state vector structure contains the translational and angular position, and the translational and angular velocity. More...

Public Types
enum	eIntegrateType { eNone = 0, eRectEuler, eTrapezoidal, eAdamsBashforth2, eAdamsBashforth3, eAdamsBashforth4, eBuss1, eBuss2, eLocalLinearization, eAdamsBashforth5 }
	These define the indices use to select the various integrators.

Public Types inherited from FGJSBBase
enum	{ eL = 1, eM, eN }
	Moments L, M, N.

enum	{ eP = 1, eQ, eR }
	Rates P, Q, R.

enum	{ eU = 1, eV, eW }
	Velocities U, V, W.

enum	{ eX = 1, eY, eZ }
	Positions X, Y, Z.

enum	{ ePhi = 1, eTht, ePsi }
	Euler angles Phi, Theta, Psi.

enum	{ eDrag = 1, eSide, eLift }
	Stability axis forces, Drag, Side force, Lift.

enum	{ eRoll = 1, ePitch, eYaw }
	Local frame orientation Roll, Pitch, Yaw.

enum	{ eNorth = 1, eEast, eDown }
	Local frame position North, East, Down.

enum	{ eLat = 1, eLong, eRad }
	Locations Radius, Latitude, Longitude.

enum	{ inNone = 0, inDegrees, inRadians, inMeters, inFeet }
	Conversion specifiers.

Public Member Functions
	FGPropagate (FGFDMExec *Executive)
	Constructor. More...

	~FGPropagate ()
	Destructor.

void	DumpState (void)

double	GetAltitudeASL (void) const
	Returns the current altitude above sea level. More...

double	GetAltitudeASLmeters (void) const
	Returns the current altitude above sea level. More...

double	GetCosEuler (int idx) const
	Retrieves the cosine of a vehicle Euler angle component. More...

double	GetDistanceAGL (void) const

double	GetDistanceAGLKm (void) const

double	GetEarthPositionAngle (void) const
	Returns the Earth position angle. More...

double	GetEarthPositionAngleDeg (void) const
	Returns the Earth position angle in degrees. More...

double	GetECEFVelocity (int idx) const
	Calculates and retrieves the velocity vector relative to the earth centered earth fixed (ECEF) frame for a particular axis.

FGColumnVector3	GetECEFVelocity (void) const
	Calculates and retrieves the velocity vector relative to the earth centered earth fixed (ECEF) frame.

double	GetEuler (int axis) const
	Retrieves a vehicle Euler angle component. More...

const FGColumnVector3 &	GetEuler (void) const
	Retrieves the Euler angles that define the vehicle orientation. More...

double	GetEulerDeg (int axis) const
	Retrieves a vehicle Euler angle component in degrees. More...

FGColumnVector3	GetEulerDeg (void) const
	Retrieves the Euler angles (in degrees) that define the vehicle orientation. More...

double	GetGeodeticAltitude (void) const

double	GetGeodeticAltitudeKm (void) const

double	GetGeodLatitudeDeg (void) const

double	GetGeodLatitudeRad (void) const

double	Gethdot (void) const
	Returns the current altitude rate. More...

double	GetInertialPosition (int i) const

const FGColumnVector3 &	GetInertialPosition (void) const
	Retrieves the inertial position vector.

double	GetInertialVelocity (int i) const

const FGColumnVector3 &	GetInertialVelocity (void) const
	Retrieves the inertial velocity vector in ft/sec.

double	GetInertialVelocityMagnitude (void) const
	Retrieves the total inertial velocity in ft/sec.

double	GetLatitude (void) const

double	GetLatitudeDeg (void) const

double	GetLocalTerrainRadius (void) const
	Returns the "constant" LocalTerrainRadius. More...

double	GetLocation (int i) const

const FGLocation &	GetLocation (void) const

double	GetLongitude (void) const

double	GetLongitudeDeg (void) const

double	GetNEDVelocityMagnitude (void) const
	Retrieves the total local NED velocity in ft/sec.

double	GetPQR (int axis) const
	Retrieves a body frame angular velocity component relative to the ECEF frame. More...

const FGColumnVector3 &	GetPQR (void) const
	Retrieves the body angular rates vector, relative to the ECEF frame. More...

double	GetPQRi (int axis) const
	Retrieves a body frame angular velocity component relative to the ECI (inertial) frame. More...

const FGColumnVector3 &	GetPQRi (void) const
	Retrieves the body angular rates vector, relative to the ECI (inertial) frame. More...

const FGQuaternion	GetQuaternion (void) const
	Returns the quaternion that goes from Local to Body.

const FGQuaternion &	GetQuaterniondot (void) const
	Retrieves the time derivative of the body orientation quaternion. More...

const FGQuaternion	GetQuaternionECEF (void) const
	Returns the quaternion that goes from ECEF to Body.

const FGQuaternion	GetQuaternionECI (void) const
	Returns the quaternion that goes from ECI to Body.

double	GetRadius (void) const

double	GetSinEuler (int idx) const
	Retrieves the sine of a vehicle Euler angle component. More...

const FGMatrix33 &	GetTb2ec (void) const
	Retrieves the body-to-ECEF transformation matrix. More...

const FGMatrix33 &	GetTb2i (void) const
	Retrieves the body-to-ECI transformation matrix. More...

const FGMatrix33 &	GetTb2l (void) const
	Retrieves the body-to-local transformation matrix. More...

const FGMatrix33 &	GetTec2b (void) const
	Retrieves the ECEF-to-body transformation matrix. More...

const FGMatrix33 &	GetTec2i (void) const
	Retrieves the ECEF-to-ECI transformation matrix. More...

const FGMatrix33 &	GetTec2l (void) const
	Retrieves the ECEF-to-local transformation matrix. More...

const FGColumnVector3 &	GetTerrainAngularVelocity (void) const

double	GetTerrainElevation (void) const

const FGColumnVector3 &	GetTerrainVelocity (void) const

const FGMatrix33 &	GetTi2b (void) const
	Retrieves the ECI-to-body transformation matrix. More...

const FGMatrix33 &	GetTi2ec (void) const
	Retrieves the ECI-to-ECEF transformation matrix. More...

const FGMatrix33 &	GetTi2l (void) const
	Retrieves the inertial-to-local transformation matrix. More...

const FGMatrix33 &	GetTl2b (void) const
	Retrieves the local-to-body transformation matrix. More...

const FGMatrix33 &	GetTl2ec (void) const
	Retrieves the local-to-ECEF transformation matrix. More...

const FGMatrix33 &	GetTl2i (void) const
	Retrieves the local-to-inertial transformation matrix. More...

double	GetUVW (int idx) const
	Retrieves a body frame velocity component. More...

const FGColumnVector3 &	GetUVW (void) const
	Retrieves the body frame vehicle velocity vector. More...

double	GetVel (int idx) const
	Retrieves a Local frame velocity component. More...

const FGColumnVector3 &	GetVel (void) const
	Retrieves the velocity vector. More...

const VehicleState &	GetVState (void) const

void	InitializeDerivatives ()

bool	InitModel (void)
	Initializes the FGPropagate class after instantiation and prior to first execution. More...

void	NudgeBodyLocation (const FGColumnVector3 &deltaLoc)

void	RecomputeLocalTerrainVelocity ()

bool	Run (bool Holding)
	Runs the state propagation model; called by the Executive Can pass in a value indicating if the executive is directing the simulation to Hold. More...

void	SetAltitudeASL (double altASL)

void	SetAltitudeASLmeters (double altASL)

void	SetDistanceAGL (double tt)

void	SetDistanceAGLKm (double tt)

void	SetEarthPositionAngle (double EPA)
	Sets the Earth position angle. More...

void	SetHoldDown (bool hd)
	Sets the property forces/hold-down. More...

void	SetInertialOrientation (const FGQuaternion &Qi)

void	SetInertialRates (const FGColumnVector3 &vRates)

void	SetInertialVelocity (const FGColumnVector3 &Vi)

void	SetInitialState (const FGInitialCondition *)

void	SetLatitude (double lat)

void	SetLatitudeDeg (double lat)

void	SetLocation (const FGColumnVector3 &lv)

void	SetLocation (const FGLocation &l)

void	SetLongitude (double lon)

void	SetLongitudeDeg (double lon)

void	SetPosition (const double Lon, const double Lat, const double Radius)

void	SetPQR (unsigned int i, double val)

void	SetRadius (double r)

void	SetTerrainElevation (double tt)

void	SetUVW (unsigned int i, double val)

void	SetVState (const VehicleState &vstate)

Public Member Functions inherited from FGModel
	FGModel (FGFDMExec *)
	Constructor.

	~FGModel () override
	Destructor.

virtual SGPath	FindFullPathName (const SGPath &path) const

FGFDMExec *	GetExec (void)

const std::string &	GetName (void)

unsigned int	GetRate (void)
	Get the output rate for the model in frames.

virtual bool	Load (Element *el)

void	SetPropertyManager (FGPropertyManager *fgpm)

void	SetRate (unsigned int tt)
	Set the ouput rate for the model in frames.

Public Member Functions inherited from FGModelFunctions
std::string	GetFunctionStrings (const std::string &delimeter) const
	Gets the strings for the current set of functions. More...

std::string	GetFunctionValues (const std::string &delimeter) const
	Gets the function values. More...

FGFunction *	GetPreFunction (const std::string &name)
	Get one of the "pre" function. More...

bool	Load (Element el, FGFDMExec fdmex, std::string prefix="")

void	PostLoad (Element el, FGFDMExec fdmex, std::string prefix="")

void	PreLoad (Element el, FGFDMExec fdmex, std::string prefix="")

void	RunPostFunctions (void)

void	RunPreFunctions (void)

Public Member Functions inherited from FGJSBBase
	FGJSBBase ()
	Constructor for FGJSBBase.

virtual	~FGJSBBase ()
	Destructor for FGJSBBase.

void	PutMessage (const Message &msg)
	Places a Message structure on the Message queue. More...

void	PutMessage (const std::string &text)
	Creates a message with the given text and places it on the queue. More...

void	PutMessage (const std::string &text, bool bVal)
	Creates a message with the given text and boolean value and places it on the queue. More...

void	PutMessage (const std::string &text, int iVal)
	Creates a message with the given text and integer value and places it on the queue. More...

void	PutMessage (const std::string &text, double dVal)
	Creates a message with the given text and double value and places it on the queue. More...

int	SomeMessages (void) const
	Reads the message on the queue (but does not delete it). More...

void	ProcessMessage (void)
	Reads the message on the queue and removes it from the queue. More...

Message *	ProcessNextMessage (void)
	Reads the next message on the queue and removes it from the queue. More...

void	disableHighLighting (void)
	Disables highlighting in the console output.

Public Attributes
struct JSBSim::FGPropagate::Inputs	in

Additional Inherited Members
Static Public Member Functions inherited from FGJSBBase
static const std::string &	GetVersion (void)
	Returns the version number of JSBSim. More...

static constexpr double	KelvinToFahrenheit (double kelvin)
	Converts from degrees Kelvin to degrees Fahrenheit. More...

static constexpr double	CelsiusToRankine (double celsius)
	Converts from degrees Celsius to degrees Rankine. More...

static constexpr double	RankineToCelsius (double rankine)
	Converts from degrees Rankine to degrees Celsius. More...

static constexpr double	KelvinToRankine (double kelvin)
	Converts from degrees Kelvin to degrees Rankine. More...

static constexpr double	RankineToKelvin (double rankine)
	Converts from degrees Rankine to degrees Kelvin. More...

static constexpr double	FahrenheitToCelsius (double fahrenheit)
	Converts from degrees Fahrenheit to degrees Celsius. More...

static constexpr double	CelsiusToFahrenheit (double celsius)
	Converts from degrees Celsius to degrees Fahrenheit. More...

static constexpr double	CelsiusToKelvin (double celsius)
	Converts from degrees Celsius to degrees Kelvin. More...

static constexpr double	KelvinToCelsius (double kelvin)
	Converts from degrees Kelvin to degrees Celsius. More...

static constexpr double	FeetToMeters (double measure)
	Converts from feet to meters. More...

static double	PitotTotalPressure (double mach, double p)
	Compute the total pressure in front of the Pitot tube. More...

static double	MachFromImpactPressure (double qc, double p)
	Compute the Mach number from the differential pressure (qc) and the static pressure. More...

static double	VcalibratedFromMach (double mach, double p)
	Calculate the calibrated airspeed from the Mach number. More...

static double	MachFromVcalibrated (double vcas, double p)
	Calculate the Mach number from the calibrated airspeed.Based on the formulas in the US Air Force Aircraft Performance Flight Testing Manual (AFFTC-TIH-99-01). More...

static bool	EqualToRoundoff (double a, double b)
	Finite precision comparison. More...

static bool	EqualToRoundoff (float a, float b)
	Finite precision comparison. More...

static bool	EqualToRoundoff (float a, double b)
	Finite precision comparison. More...

static bool	EqualToRoundoff (double a, float b)
	Finite precision comparison. More...

static constexpr double	Constrain (double min, double value, double max)
	Constrain a value between a minimum and a maximum value.

static constexpr double	sign (double num)

static double	GaussianRandomNumber (void)

Static Public Attributes inherited from FGJSBBase
static char	highint [5] = {27, '[', '1', 'm', '\0' }
	highlights text

static char	halfint [5] = {27, '[', '2', 'm', '\0' }
	low intensity text

static char	normint [6] = {27, '[', '2', '2', 'm', '\0' }
	normal intensity text

static char	reset [5] = {27, '[', '0', 'm', '\0' }
	resets text properties

static char	underon [5] = {27, '[', '4', 'm', '\0' }
	underlines text

static char	underoff [6] = {27, '[', '2', '4', 'm', '\0' }
	underline off

static char	fgblue [6] = {27, '[', '3', '4', 'm', '\0' }
	blue text

static char	fgcyan [6] = {27, '[', '3', '6', 'm', '\0' }
	cyan text

static char	fgred [6] = {27, '[', '3', '1', 'm', '\0' }
	red text

static char	fggreen [6] = {27, '[', '3', '2', 'm', '\0' }
	green text

static char	fgdef [6] = {27, '[', '3', '9', 'm', '\0' }
	default text

static short	debug_lvl = 1

Protected Member Functions inherited from FGModel
bool	Upload (Element *el, bool preLoad)
	Uploads this model in memory. More...

Static Protected Member Functions inherited from FGJSBBase
static std::string	CreateIndexedPropertyName (const std::string &Property, int index)

Protected Attributes inherited from FGModel
unsigned int	exe_ctr

FGFDMExec *	FDMExec

std::string	Name

FGPropertyManager *	PropertyManager

unsigned int	rate

Protected Attributes inherited from FGModelFunctions
FGPropertyReader	LocalProperties

std::vector< FGFunction * >	PostFunctions

std::vector< FGFunction * >	PreFunctions

Static Protected Attributes inherited from FGJSBBase
static Message	localMsg

static std::queue< Message >	Messages

static unsigned int	messageId = 0

static constexpr double	radtodeg = 180. / M_PI

static constexpr double	degtorad = M_PI / 180.

static constexpr double	hptoftlbssec = 550.0

static constexpr double	psftoinhg = 0.014138

static constexpr double	psftopa = 47.88

static constexpr double	ktstofps = 1.68781

static constexpr double	fpstokts = 1.0 / ktstofps

static constexpr double	inchtoft = 1.0/12.0

static constexpr double	fttom = 0.3048

static constexpr double	m3toft3 = 1.0/(fttomfttomfttom)

static constexpr double	in3tom3 = inchtoftinchtoftinchtoft/m3toft3

static constexpr double	inhgtopa = 3386.38

static constexpr double	slugtolb = 32.174049
	Note that definition of lbtoslug by the inverse of slugtolb and not to a different constant you can also get from some tables will make lbtoslug*slugtolb == 1 up to the magnitude of roundoff. More...

static constexpr double	lbtoslug = 1.0/slugtolb

static constexpr double	kgtolb = 2.20462

static constexpr double	kgtoslug = 0.06852168

static const std::string	needed_cfg_version = "2.0"

static const std::string	JSBSim_version = JSBSIM_VERSION " " __DATE__ " " __TIME__

static int	gaussian_random_number_phase = 0

Constructor & Destructor Documentation

◆ FGPropagate()

FGPropagate ( FGFDMExec * Executive )

explicit

Constructor.

The constructor initializes several variables, and sets the initial set of integrators to use as follows:

integrator, rotational rate = Adams Bashforth 2
integrator, translational rate = Adams Bashforth 2
integrator, rotational position = Trapezoidal
integrator, translational position = Trapezoidal
Parameters

Executive a pointer to the parent executive object

These define the indices use to select the various integrators.

Definition at line 82 of file FGPropagate.cpp.

   : FGModel(fdmex)
 {
   Debug(0);
   Name = "FGPropagate";
  
   Inertial = FDMExec->GetInertial();
  
   // eNone = 0, eRectEuler, eTrapezoidal, eAdamsBashforth2, eAdamsBashforth3, eAdamsBashforth4};
  
   integrator_rotational_rate = eRectEuler;
   integrator_translational_rate = eAdamsBashforth2;
   integrator_rotational_position = eRectEuler;
   integrator_translational_position = eAdamsBashforth3;
  
   VState.dqPQRidot.resize(5, FGColumnVector3(0.0,0.0,0.0));
   VState.dqUVWidot.resize(5, FGColumnVector3(0.0,0.0,0.0));
   VState.dqInertialVelocity.resize(5, FGColumnVector3(0.0,0.0,0.0));
   VState.dqQtrndot.resize(5, FGQuaternion(0.0,0.0,0.0));
  
   epa = 0.0;
  
   bind();
   Debug(0);
 }

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Member Function Documentation

◆ GetAltitudeASL()

double GetAltitudeASL ( void ) const

Returns the current altitude above sea level.

This function returns the altitude above sea level. units ft

Returns: The current altitude above sea level in feet.

Definition at line 523 of file FGPropagate.cpp.

 {
   return VState.vLocation.GetRadius() - VState.vLocation.GetSeaLevelRadius();
 }

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◆ GetAltitudeASLmeters()

double GetAltitudeASLmeters ( void ) const

inline

Returns the current altitude above sea level.

This function returns the altitude above sea level. units meters

Returns: The current altitude above sea level in meters.

Definition at line 335 of file FGPropagate.h.

335 { return GetAltitudeASL()*fttom;}

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◆ GetCosEuler()

double GetCosEuler ( int idx ) const

inline

Retrieves the cosine of a vehicle Euler angle component.

Retrieves the cosine of an Euler angle (Phi, Theta, or Psi) from the quaternion that stores the vehicle orientation relative to the Local frame. The order of rotations used is Yaw-Pitch-Roll. The Euler angle with subscript (1) is Phi. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the Euler angle referred to in this call are, ePhi=1, eTht=2, ePsi=3 (e.g. GetCosEuler(eTht) returns cos(theta)). units none

Returns: The cosine of an Euler angle.

Definition at line 397 of file FGPropagate.h.

397 { return VState.qAttitudeLocal.GetCosEuler(idx); }

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◆ GetEarthPositionAngle()

double GetEarthPositionAngle ( void ) const

inline

Returns the Earth position angle.

Returns: Earth position angle in radians.

Definition at line 429 of file FGPropagate.h.

429 { return epa; }

◆ GetEarthPositionAngleDeg()

double GetEarthPositionAngleDeg ( void ) const

inline

Returns the Earth position angle in degrees.

Returns: Earth position angle in degrees.

Definition at line 434 of file FGPropagate.h.

434 { return epa*radtodeg;}

◆ GetEuler() [1/2]

double GetEuler ( int axis ) const

inline

Retrieves a vehicle Euler angle component.

Retrieves an Euler angle (Phi, Theta, or Psi) from the quaternion that stores the vehicle orientation relative to the Local frame. The order of rotations used is Yaw-Pitch-Roll. The Euler angle with subscript (1) is Phi. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the Euler angle returned by this call are, ePhi=1, eTht=2, ePsi=3 (e.g. GetEuler(eTht) returns Theta). units radians

Returns: An Euler angle.

Definition at line 373 of file FGPropagate.h.

373 { return VState.qAttitudeLocal.GetEuler(axis); }

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◆ GetEuler() [2/2]

const FGColumnVector3& GetEuler ( void ) const

inline

Retrieves the Euler angles that define the vehicle orientation.

Extracts the Euler angles from the quaternion that stores the orientation in the Local frame. The order of rotation used is Yaw-Pitch-Roll. The vector returned is represented by an FGColumnVector reference. The vector for the Euler angles is organized (Phi, Theta, Psi). The vector is 1-based, so that the first element can be retrieved using the "()" operator. In other words, the returned vector item with subscript (1) is Phi. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the vector returned by this call are, ePhi=1, eTht=2, ePsi=3. units radians

Returns: The Euler angle vector, where the first item in the vector is the angle about the X axis, the second is the angle about the Y axis, and the third item is the angle about the Z axis (Phi, Theta, Psi).

Definition at line 251 of file FGPropagate.h.

251 { return VState.qAttitudeLocal.GetEuler(); }

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◆ GetEulerDeg() [1/2]

double GetEulerDeg ( int axis ) const

inline

Retrieves a vehicle Euler angle component in degrees.

Retrieves an Euler angle (Phi, Theta, or Psi) from the quaternion that stores the vehicle orientation relative to the Local frame. The order of rotations used is Yaw-Pitch-Roll. The Euler angle with subscript (1) is Phi. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the Euler angle returned by this call are, ePhi=1, eTht=2, ePsi=3 (e.g. GetEuler(eTht) returns Theta). units degrees

Returns: An Euler angle in degrees.

Definition at line 385 of file FGPropagate.h.

385 { return VState.qAttitudeLocal.GetEuler(axis) * radtodeg; }

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◆ GetEulerDeg() [2/2]

FGColumnVector3 GetEulerDeg ( void ) const

Retrieves the Euler angles (in degrees) that define the vehicle orientation.

Extracts the Euler angles from the quaternion that stores the orientation in the Local frame. The order of rotation used is Yaw-Pitch-Roll. The vector returned is represented by an FGColumnVector reference. The vector for the Euler angles is organized (Phi, Theta, Psi). The vector is 1-based, so that the first element can be retrieved using the "()" operator. In other words, the returned vector item with subscript (1) is Phi. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the vector returned by this call are, ePhi=1, eTht=2, ePsi=3. units degrees

Returns: The Euler angle vector, where the first item in the vector is the angle about the X axis, the second is the angle about the Y axis, and the third item is the angle about the Z axis (Phi, Theta, Psi).

Definition at line 643 of file FGPropagate.cpp.

 {
   return VState.qAttitudeLocal.GetEuler() * radtodeg;
 }

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◆ Gethdot()

double Gethdot ( void ) const

inline

Returns the current altitude rate.

Returns the current altitude rate (rate of climb). units ft/sec

Returns: The current rate of change in altitude.

Definition at line 416 of file FGPropagate.h.

416 { return -vVel(eDown); }

◆ GetLocalTerrainRadius()

double GetLocalTerrainRadius ( void ) const

Returns the "constant" LocalTerrainRadius.

The LocalTerrainRadius parameter is set by the calling application or set to sea level + terrain elevation if JSBSim is running in standalone mode. units feet

Returns: distance of the local terrain from the center of the earth.

Definition at line 567 of file FGPropagate.cpp.

 {
   FGLocation contact;
   FGColumnVector3 vDummy;
   Inertial->GetContactPoint(VState.vLocation, contact, vDummy, vDummy, vDummy);
   return contact.GetRadius();
 }

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◆ GetPQR() [1/2]

double GetPQR ( int axis ) const

inline

Retrieves a body frame angular velocity component relative to the ECEF frame.

Retrieves a body frame angular velocity component. The angular velocity returned is extracted from the vPQR vector (an FGColumnVector). The vector for the angular velocity in Body frame is organized (P, Q, R). The vector is 1-based. In other words, GetPQR(1) returns P (roll rate). Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the angular velocity returned by this call are, eP=1, eQ=2, eR=3. units rad/sec

Parameters

axis	the index of the angular velocity component desired (1-based).

Returns: The body frame angular velocity component.

Definition at line 348 of file FGPropagate.h.

348 {return VState.vPQR(axis);}

◆ GetPQR() [2/2]

const FGColumnVector3& GetPQR ( void ) const

inline

Retrieves the body angular rates vector, relative to the ECEF frame.

Retrieves the body angular rates (p, q, r), which are calculated by integration of the angular acceleration. The vector returned is represented by an FGColumnVector3 reference. The vector for the angular velocity in Body frame is organized (P, Q, R). The vector is 1-based, so that the first element can be retrieved using the "()" operator. In other words, vPQR(1) is P. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the vector returned by this call are, eP=1, eQ=2, eR=3. units rad/sec

Returns: The body frame angular rates in rad/sec.

Definition at line 209 of file FGPropagate.h.

209 {return VState.vPQR;}

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◆ GetPQRi() [1/2]

double GetPQRi ( int axis ) const

inline

Retrieves a body frame angular velocity component relative to the ECI (inertial) frame.

Retrieves a body frame angular velocity component. The angular velocity returned is extracted from the vPQR vector (an FGColumnVector). The vector for the angular velocity in Body frame is organized (P, Q, R). The vector is 1-based. In other words, GetPQR(1) returns P (roll rate). Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the angular velocity returned by this call are, eP=1, eQ=2, eR=3. units rad/sec

Parameters

axis	the index of the angular velocity component desired (1-based).

Returns: The body frame angular velocity component.

Definition at line 361 of file FGPropagate.h.

361 {return VState.vPQRi(axis);}

◆ GetPQRi() [2/2]

const FGColumnVector3& GetPQRi ( void ) const

inline

Retrieves the body angular rates vector, relative to the ECI (inertial) frame.

Retrieves the body angular rates (p, q, r), which are calculated by integration of the angular acceleration. The vector returned is represented by an FGColumnVector reference. The vector for the angular velocity in Body frame is organized (P, Q, R). The vector is 1-based, so that the first element can be retrieved using the "()" operator. In other words, vPQR(1) is P. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the vector returned by this call are, eP=1, eQ=2, eR=3. units rad/sec

Returns: The body frame inertial angular rates in rad/sec.

Definition at line 223 of file FGPropagate.h.

223 {return VState.vPQRi;}

◆ GetQuaterniondot()

const FGQuaternion& GetQuaterniondot ( void ) const

inline

Retrieves the time derivative of the body orientation quaternion.

Retrieves the time derivative of the body orientation quaternion based on the rate of change of the orientation between the body and the ECI frame. The quaternion returned is represented by an FGQuaternion reference. The quaternion is 1-based, so that the first element can be retrieved using the "()" operator. units rad/sec^2

Returns: The time derivative of the body orientation quaternion.

Definition at line 234 of file FGPropagate.h.

234 {return VState.vQtrndot;}

◆ GetSinEuler()

double GetSinEuler ( int idx ) const

inline

Retrieves the sine of a vehicle Euler angle component.

Retrieves the sine of an Euler angle (Phi, Theta, or Psi) from the quaternion that stores the vehicle orientation relative to the Local frame. The order of rotations used is Yaw-Pitch-Roll. The Euler angle with subscript (1) is Phi. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the Euler angle referred to in this call are, ePhi=1, eTht=2, ePsi=3 (e.g. GetSinEuler(eTht) returns sin(theta)). units none

Returns: The sine of an Euler angle.

Definition at line 409 of file FGPropagate.h.

409 { return VState.qAttitudeLocal.GetSinEuler(idx); }

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◆ GetTb2ec()

const FGMatrix33& GetTb2ec ( void ) const

inline

Retrieves the body-to-ECEF transformation matrix.

Returns: a reference to the body-to-ECEF matrix.

Definition at line 479 of file FGPropagate.h.

479 { return Tb2ec; }

◆ GetTb2i()

const FGMatrix33& GetTb2i ( void ) const

inline

Retrieves the body-to-ECI transformation matrix.

Returns: a reference to the body-to-ECI matrix.

Definition at line 487 of file FGPropagate.h.

487 { return Tb2i; }

◆ GetTb2l()

const FGMatrix33& GetTb2l ( void ) const

inline

Retrieves the body-to-local transformation matrix.

The quaternion class, being the means by which the orientation of the vehicle is stored, manages the body-to-local transformation matrix.

Returns: a reference to the body-to-local matrix.

Definition at line 471 of file FGPropagate.h.

471 { return Tb2l; }

◆ GetTec2b()

const FGMatrix33& GetTec2b ( void ) const

inline

Retrieves the ECEF-to-body transformation matrix.

Returns: a reference to the ECEF-to-body transformation matrix.

Definition at line 475 of file FGPropagate.h.

475 { return Tec2b; }

◆ GetTec2i()

const FGMatrix33& GetTec2i ( void ) const

inline

Retrieves the ECEF-to-ECI transformation matrix.

Returns: a reference to the ECEF-to-ECI transformation matrix.

See also: SetEarthPositionAngle

Definition at line 492 of file FGPropagate.h.

492 { return Tec2i; }

◆ GetTec2l()

const FGMatrix33& GetTec2l ( void ) const

inline

Retrieves the ECEF-to-local transformation matrix.

Retrieves the ECEF-to-local transformation matrix. Note that the so-called local from is also know as the NED frame (for North, East, Down).

Returns: a reference to the ECEF-to-local matrix.

Definition at line 503 of file FGPropagate.h.

503 { return Tec2l; }

◆ GetTi2b()

const FGMatrix33& GetTi2b ( void ) const

inline

Retrieves the ECI-to-body transformation matrix.

Returns: a reference to the ECI-to-body transformation matrix.

Definition at line 483 of file FGPropagate.h.

483 { return Ti2b; }

◆ GetTi2ec()

const FGMatrix33& GetTi2ec ( void ) const

inline

Retrieves the ECI-to-ECEF transformation matrix.

Returns: a reference to the ECI-to-ECEF matrix.

See also: SetEarthPositionAngle

Definition at line 497 of file FGPropagate.h.

497 { return Ti2ec; }

◆ GetTi2l()

const FGMatrix33& GetTi2l ( void ) const

inline

Retrieves the inertial-to-local transformation matrix.

Returns: a reference to the inertial-to-local matrix.

See also: SetEarthPositionAngle

Definition at line 519 of file FGPropagate.h.

519 { return Ti2l; }

◆ GetTl2b()

const FGMatrix33& GetTl2b ( void ) const

inline

Retrieves the local-to-body transformation matrix.

The quaternion class, being the means by which the orientation of the vehicle is stored, manages the local-to-body transformation matrix.

Returns: a reference to the local-to-body transformation matrix.

Definition at line 465 of file FGPropagate.h.

465 { return Tl2b; }

◆ GetTl2ec()

const FGMatrix33& GetTl2ec ( void ) const

inline

Retrieves the local-to-ECEF transformation matrix.

Retrieves the local-to-ECEF transformation matrix. Note that the so-called local from is also know as the NED frame (for North, East, Down).

Returns: a reference to the local-to-ECEF matrix.

Definition at line 509 of file FGPropagate.h.

509 { return Tl2ec; }

◆ GetTl2i()

const FGMatrix33& GetTl2i ( void ) const

inline

Retrieves the local-to-inertial transformation matrix.

Returns: a reference to the local-to-inertial transformation matrix.

See also: SetEarthPositionAngle

Definition at line 514 of file FGPropagate.h.

514 { return Tl2i; }

◆ GetUVW() [1/2]

double GetUVW ( int idx ) const

inline

Retrieves a body frame velocity component.

Retrieves a body frame velocity component. The velocity returned is extracted from the vUVW vector (an FGColumnVector). The vector for the velocity in Body frame is organized (Vx, Vy, Vz). The vector is 1-based. In other words, GetUVW(1) returns Vx. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the velocity returned by this call are, eX=1, eY=2, eZ=3. units ft/sec

Parameters

idx	the index of the velocity component desired (1-based).

Returns: The body frame velocity component.

Definition at line 281 of file FGPropagate.h.

281 { return VState.vUVW(idx); }

◆ GetUVW() [2/2]

const FGColumnVector3& GetUVW ( void ) const

inline

Retrieves the body frame vehicle velocity vector.

The vector returned is represented by an FGColumnVector3 reference. The vector for the velocity in Body frame is organized (Vx, Vy, Vz). The vector is 1-based, so that the first element can be retrieved using the "()" operator. In other words, vUVW(1) is Vx. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the vector returned by this call are, eX=1, eY=2, eZ=3. units ft/sec

Returns: The body frame vehicle velocity vector in ft/sec.

Definition at line 195 of file FGPropagate.h.

195 { return VState.vUVW; }

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◆ GetVel() [1/2]

double GetVel ( int idx ) const

inline

Retrieves a Local frame velocity component.

Retrieves a Local frame velocity component. The velocity returned is extracted from the vVel vector (an FGColumnVector). The vector for the velocity in Local frame is organized (Vnorth, Veast, Vdown). The vector is 1-based. In other words, GetVel(1) returns Vnorth. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the velocity returned by this call are, eNorth=1, eEast=2, eDown=3. units ft/sec

Parameters

idx	the index of the velocity component desired (1-based).

Returns: The body frame velocity component.

Definition at line 294 of file FGPropagate.h.

294 { return vVel(idx); }

◆ GetVel() [2/2]

const FGColumnVector3& GetVel ( void ) const

inline

Retrieves the velocity vector.

The vector returned is represented by an FGColumnVector reference. The vector for the velocity in Local frame is organized (Vnorth, Veast, Vdown). The vector is 1-based, so that the first element can be retrieved using the "()" operator. In other words, vVel(1) is Vnorth. Various convenience enumerators are defined in FGJSBBase. The relevant enumerators for the vector returned by this call are, eNorth=1, eEast=2, eDown=3. units ft/sec

Returns: The vehicle velocity vector with respect to the Earth centered frame, expressed in Local horizontal frame.

Definition at line 183 of file FGPropagate.h.

183 { return vVel; }

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◆ InitModel()

bool InitModel ( void )

virtual

Initializes the FGPropagate class after instantiation and prior to first execution.

The base class FGModel::InitModel is called first, initializing pointers to the other FGModel objects (and others).

Reimplemented from FGModel.

Definition at line 118 of file FGPropagate.cpp.

 {
   if (!FGModel::InitModel()) return false;
  
   // For initialization ONLY:
   VState.vLocation.SetEllipse(in.SemiMajor, in.SemiMinor);
   Inertial->SetAltitudeAGL(VState.vLocation, 4.0);
  
   VState.dqPQRidot.resize(5, FGColumnVector3(0.0,0.0,0.0));
   VState.dqUVWidot.resize(5, FGColumnVector3(0.0,0.0,0.0));
   VState.dqInertialVelocity.resize(5, FGColumnVector3(0.0,0.0,0.0));
   VState.dqQtrndot.resize(5, FGColumnVector3(0.0,0.0,0.0));
  
   integrator_rotational_rate = eRectEuler;
   integrator_translational_rate = eAdamsBashforth2;
   integrator_rotational_position = eRectEuler;
   integrator_translational_position = eAdamsBashforth3;
  
   epa = 0.0;
  
   return true;
 }

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◆ Run()

bool Run ( bool Holding )

virtual

Runs the state propagation model; called by the Executive Can pass in a value indicating if the executive is directing the simulation to Hold.

Parameters

Holding if true, the executive has been directed to hold the sim from advancing time. Some models may ignore this flag, such as the Input model, which may need to be active to listen on a socket for the "Resume" command to be given.

Returns: false if no error

Reimplemented from FGModel.

Definition at line 218 of file FGPropagate.cpp.

 {
   if (FGModel::Run(Holding)) return true;  // Fast return if we have nothing to do ...
   if (Holding) return false;
  
   double dt = in.DeltaT * rate;  // The 'stepsize'
  
   // Propagate rotational / translational velocity, angular /translational position, respectively.
  
   if (!FDMExec->IntegrationSuspended()) {
     Integrate(VState.qAttitudeECI,      VState.vQtrndot,      VState.dqQtrndot,          dt, integrator_rotational_position);
     Integrate(VState.vPQRi,             in.vPQRidot,          VState.dqPQRidot,          dt, integrator_rotational_rate);
     Integrate(VState.vInertialPosition, VState.vInertialVelocity, VState.dqInertialVelocity, dt, integrator_translational_position);
     Integrate(VState.vInertialVelocity, in.vUVWidot,          VState.dqUVWidot,          dt, integrator_translational_rate);
   }
  
   // CAUTION : the order of the operations below is very important to get
   // transformation matrices that are consistent with the new state of the
   // vehicle
  
   // 1. Update the Earth position angle (EPA)
   epa += in.vOmegaPlanet(eZ)*dt;
  
   // 2. Update the Ti2ec and Tec2i transforms from the updated EPA
   double cos_epa = cos(epa);
   double sin_epa = sin(epa);
   Ti2ec = { cos_epa, sin_epa, 0.0,
             -sin_epa, cos_epa, 0.0,
             0.0, 0.0, 1.0 };
   Tec2i = Ti2ec.Transposed();          // ECEF to ECI frame transform
  
   // 3. Update the location from the updated Ti2ec and inertial position
   VState.vLocation = Ti2ec*VState.vInertialPosition;
  
   // 4. Update the other "Location-based" transformation matrices from the
   //    updated vLocation vector.
   UpdateLocationMatrices();
  
   // 5. Update the "Orientation-based" transformation matrices from the updated
   //    orientation quaternion and vLocation vector.
   UpdateBodyMatrices();
  
   // Translational position derivative (velocities are integrated in the
   // inertial frame)
   CalculateUVW();
  
   // Set auxilliary state variables
   RecomputeLocalTerrainVelocity();
  
   VState.vPQR = VState.vPQRi - Ti2b * in.vOmegaPlanet;
  
   // Angular orientation derivative
   CalculateQuatdot();
  
   VState.qAttitudeLocal = Tl2b.GetQuaternion();
  
   // Compute vehicle velocity wrt ECEF frame, expressed in Local horizontal
   // frame.
   vVel = Tb2l * VState.vUVW;
  
   Debug(2);
   return false;
 }

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◆ SetEarthPositionAngle()

void SetEarthPositionAngle ( double EPA )

inline

Sets the Earth position angle.

This is the relative angle around the Z axis of the ECEF frame with respect to the inertial frame.

Parameters

EPA	Earth position angle in radians.

Definition at line 530 of file FGPropagate.h.

530 {epa = EPA;}

◆ SetHoldDown()

void SetHoldDown ( bool hd )

Sets the property forces/hold-down.

This allows to do hard 'hold-down' such as for rockets on a launch pad with engines ignited.

Parameters

hd	enables the 'hold-down' function if non-zero

Definition at line 284 of file FGPropagate.cpp.

 {
   if (hd) {
     VState.vUVW.InitMatrix();
     CalculateInertialVelocity();
     VState.vPQR.InitMatrix();
     VState.vPQRi = Ti2b * in.vOmegaPlanet;
     CalculateQuatdot();
     InitializeDerivatives();
   }
 }

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

Detailed Description

Classes

Public Types

Public Member Functions

Public Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ FGPropagate()

Member Function Documentation

◆ GetAltitudeASL()

◆ GetAltitudeASLmeters()

◆ GetCosEuler()

◆ GetEarthPositionAngle()

◆ GetEarthPositionAngleDeg()

◆ GetEuler() [1/2]

◆ GetEuler() [2/2]

◆ GetEulerDeg() [1/2]

◆ GetEulerDeg() [2/2]

◆ Gethdot()

◆ GetLocalTerrainRadius()

◆ GetPQR() [1/2]

◆ GetPQR() [2/2]

◆ GetPQRi() [1/2]

◆ GetPQRi() [2/2]

◆ GetQuaterniondot()

◆ GetSinEuler()

◆ GetTb2ec()

◆ GetTb2i()

◆ GetTb2l()

◆ GetTec2b()

◆ GetTec2i()

◆ GetTec2l()

◆ GetTi2b()

◆ GetTi2ec()

◆ GetTi2l()

◆ GetTl2b()

◆ GetTl2ec()

◆ GetTl2i()

◆ GetUVW() [1/2]

◆ GetUVW() [2/2]

◆ GetVel() [1/2]

◆ GetVel() [2/2]

◆ InitModel()

◆ Run()

◆ SetEarthPositionAngle()

◆ SetHoldDown()