An abstract observer location. More...

#include <supernovas.h>

Inheritance diagram for supernovas::Observer:

Public Member Functions
virtual	~Observer ()
const observer *	_novas_observer () const
	Returns the underlying NOVAS C observer data structure.
virtual const Observer *	copy () const
	Returns a newly allocated copy of this observer.
virtual bool	equals (const Observer &other) const
	Checks if this observer is essentially the same as the other, within the tolerances associated to their defining components.
Frame	frame_at (const Time &time, enum novas_accuracy accuracy=NOVAS_FULL_ACCURACY) const
	Returns an observing frame for this observer at the specified time and optionally with a specified accuracy.
virtual bool	is_geocentric () const
	Checks if this observer can be cast to a GeocentricObserver.
virtual bool	is_geodetic () const
	Checks if this observer can be cast to a GeodeticObserver.
bool	operator!= (const Observer &other) const
	Checks if two observers differ given standard tolerances associated to their defining components.
bool	operator== (const Observer &other) const
	Checks if two observers are essentially the same within the tolerances associated to their defining components.
Frame	reduced_accuracy_frame_at (const Time &time) const
	Returns a reduced accuracy observing frame for this observer at the specified time.
Interferometric	to_interferometric (const Apparent &phase_center, enum novas_reference_system system=NOVAS_ICRS) const
	Returns projected u,v,w coordinates for an interferometer station.
virtual std::string	to_string () const
	Returns a string representation of this observer.
enum novas_observer_place	type () const
	Returns the observer type.
Public Member Functions inherited from supernovas::Validating
bool	is_valid () const
	Returns the previously set 'valid' stae of the implementing instance.
	operator bool () const
	Objects that implement Validating can be used in conditionals directly, without explicitly calling is_valid().

Static Public Member Functions
static GeocentricObserver	at_geocenter ()
	Returns a fictitious observer placed at the location of the geocenter.
static SolarSystemObserver	at_ssb ()
	Returns a fictitious observer placed at the location of the Solar-System Barycenter (SSB).
static GeocentricObserver	in_earth_orbit (const Position &pos, const Velocity &vel)
	Returns a new observer orbiting the Earth.
static SolarSystemObserver	in_solar_system (const Position &pos, const Velocity &vel)
	Returns a new observer in some Solar-system location.
static GeodeticObserver	moving_on_earth (const Site &site, const EOP &eop, const ScalarVelocity &horizontal, const Angle &direction, const ScalarVelocity &vertical=ScalarVelocity::stationary())
	Instantiates a new observer that is moving relative to Earth's surface, such as an airborne observer.
static GeodeticObserver	moving_on_earth (const Site &site, const Velocity &itrs_vel, const EOP &eop=EOP::undefined())
	Returns a new observer that is moving, at some velocitym relative to Earth's surface, such as an airborne aircraft or balloon based observatory.
static GeodeticObserver	on_earth (const Site &site, const EOP &eop=EOP::undefined())
	Returns a new observer located at a fixed observing site.
static const Observer &	undefined ()
	Returns a reference to a statically defined standard invalid observer.

Protected Member Functions
	Observer (enum novas_observer_place type, const Site &site=Site::undefined(), const Position &pos=Position::origin(), const Velocity &vel=Velocity::stationary())
virtual Position	gcrs_position_at (const Time &time, enum novas_accuracy accuracy=NOVAS_FULL_ACCURACY) const
	Returns the geocentric geometric position vector for this observer, in the GCRS, at the specified time and accuracy.
virtual Velocity	gcrs_velocity_at (const Time &time, enum novas_accuracy accuracy=NOVAS_FULL_ACCURACY) const
	Returns the geocentric geometric velocity vector for this observer, in the GCRS, at the specified time and accuracy.
Protected Member Functions inherited from supernovas::Validating
	Validating ()
	dummy constructor;

Protected Attributes
observer	_observer = {}
	stored observer data
Protected Attributes inherited from supernovas::Validating
bool	_valid = false
	the state variable.

Detailed Description

An abstract observer location.

Both Earth-bound (geodetic sites, airborne, or Earth-orbit) locations, and locations elsewhere in the Solar-system are supported. See the static methods of this class for instantiating different subclasses as appropriate.

Since: 1.6

See also: Frame

Constructor & Destructor Documentation

◆ Observer()

supernovas::Observer::Observer	(	enum novas_observer_place	type,
		const Site &	site = Site::undefined(),
		const Position &	pos = Position::origin(),
		const Velocity &	vel = Velocity::stationary() )

explicitprotected

References _observer, supernovas::Site::_on_surface(), supernovas::Unit::AU, supernovas::Unit::AU_per_day, supernovas::Unit::km, supernovas::Unit::km_per_s, NOVAS_SOLAR_SYSTEM_OBSERVER, and type().

◆ ~Observer()

virtual supernovas::Observer::~Observer ( )

inlinevirtual

Member Function Documentation

◆ _novas_observer()

const observer * supernovas::Observer::_novas_observer ( ) const

Returns the underlying NOVAS C observer data structure.

Returns: pointer to the underlying C observer data structure.

Since: 1.6

References _novas_observer(), and _observer.

Referenced by supernovas::Frame::Frame(), and _novas_observer().

◆ at_geocenter()

GeocentricObserver supernovas::Observer::at_geocenter ( )

static

Returns a fictitious observer placed at the location of the geocenter.

Returns: a new fictitious observer located at the geocenter.

Since: 1.6

See also: on_earth(), in_earth_orbit(), in_solar_system(), at_ssb()

References at_geocenter().

Referenced by at_geocenter().

◆ at_ssb()

SolarSystemObserver supernovas::Observer::at_ssb ( )

static

Returns a fictitious observer placed at the location of the Solar-System Barycenter (SSB).

Returns: a new fictitious observer located at the Solar-System Barycenter (SSB).

Since: 1.6

See also: in_solar_system(), at_geocenter(), on_earth(), in_earth_orbit()

References at_ssb().

Referenced by at_ssb(), and supernovas::SolarSystemSource::barycentric_at().

◆ copy()

const Observer * supernovas::Observer::copy ( ) const

virtual

Returns a newly allocated copy of this observer.

The default implementation returns an invalid observer, but concrete subclasses should override that to return their onw copies.

Returns: a copy of this observer class, which may be an invalid observer (default).

Since: 1.6

Reimplemented in supernovas::GeocentricObserver, supernovas::GeodeticObserver, and supernovas::SolarSystemObserver.

References copy().

Referenced by copy(), and supernovas::Frame::operator=().

◆ equals()

bool supernovas::Observer::equals ( const Observer & other ) const

virtual

Checks if this observer is essentially the same as the other, within the tolerances associated to their defining components.

Note, that an observer may not equal itself if it contains NAN or infinite components.

Parameters

other the other observer

Returns: true if both observers effectively describe the same observing location, within tolerances, or else false.

Since: 1.7

See also: operator==(), operator!=()

Reimplemented in supernovas::GeodeticObserver.

References _observer, equals(), and novas_equals_observer().

Referenced by supernovas::GeodeticObserver::equals(), equals(), operator!=(), and operator==().

◆ gcrs_position_at()

Position supernovas::Observer::gcrs_position_at	(	const Time &	time,
		enum novas_accuracy	accuracy = NOVAS_FULL_ACCURACY ) const

protectedvirtual

Returns the geocentric geometric position vector for this observer, in the GCRS, at the specified time and accuracy.

Parameters

Time of observation and astronomical timescales	Astrometric time of observation
accuracy	(optional) NOVAS_FULL_ACCURACY (default) or NOVAS_REDUCED_ACCURACY.

Returns: The ICRS geometric geocentric position vector of this observer at the specified time.

Since: 1.6

See also: gcrs_velocity_at()

Reimplemented in supernovas::GeodeticObserver.

References supernovas::Time::_novas_timespec(), _observer, supernovas::Unit::AU, gcrs_position_at(), geo_posvel(), supernovas::Time::jd(), supernovas::Position::undefined(), and novas_timespec::ut1_to_tt.

Referenced by gcrs_position_at(), and to_interferometric().

◆ gcrs_velocity_at()

Velocity supernovas::Observer::gcrs_velocity_at	(	const Time &	time,
		enum novas_accuracy	accuracy = NOVAS_FULL_ACCURACY ) const

protectedvirtual

Returns the geocentric geometric velocity vector for this observer, in the GCRS, at the specified time and accuracy.

Parameters

Time of observation and astronomical timescales	Astrometric time of observation
accuracy	(optional) NOVAS_FULL_ACCURACY (default) or NOVAS_REDUCED_ACCURACY.

Returns: The ICRS geometric geocentric velocity vector of this observer at the specified time.

Since: 1.6

See also: gcrs_position_at()

Reimplemented in supernovas::GeodeticObserver.

References supernovas::Time::_novas_timespec(), _observer, supernovas::Unit::AU, gcrs_velocity_at(), geo_posvel(), supernovas::Time::jd(), supernovas::Velocity::undefined(), and novas_timespec::ut1_to_tt.

Referenced by gcrs_velocity_at(), and to_interferometric().

◆ in_earth_orbit()

GeocentricObserver supernovas::Observer::in_earth_orbit	(	const Position &	pos,
		const Velocity &	vel )

static

Returns a new observer orbiting the Earth.

Parameters

pos	momentary position of the observer relative to the geocenter.
vel	momentary velocity of the observer relative to the geocenter.

Returns: a new observer instance for the observer in Earth orbit.

Since: 1.6

See also: on_earth(), in_solar_system(), at_geocenter(), at_ssb()

References in_earth_orbit(), and supernovas::Validating::is_valid().

Referenced by in_earth_orbit().

◆ in_solar_system()

SolarSystemObserver supernovas::Observer::in_solar_system	(	const Position &	pos,
		const Velocity &	vel )

static

Returns a new observer in some Solar-system location.

Parameters

pos	momentary position of the observer relative to the Solar-system Barycenter (SSB).
vel	momentary velocity of the observer relative to the Solar-system Barycenter (SSB).

Returns: a new observer instance for the given Solar-system location.

Since: 1.6

See also: at_ssb(), at_geocenter(), on_earth(), in_earth_orbit()

References in_solar_system(), and supernovas::Validating::is_valid().

Referenced by in_solar_system().

◆ is_geocentric()

bool supernovas::Observer::is_geocentric ( ) const

virtual

Checks if this observer can be cast to a GeocentricObserver.

Returns: true if this observer is an instance of GeocentricObserver, otherwise false.

Since: 1.6

See also: GeocentricObserver, is_geodetic()

Reimplemented in supernovas::GeocentricObserver.

References is_geocentric().

Referenced by is_geocentric().

◆ is_geodetic()

bool supernovas::Observer::is_geodetic ( ) const

virtual

Checks if this observer can be cast to a GeodeticObserver.

Returns: true is this observer is an instance of GeodeticObserver, otherwise false.

Since: 1.6

See also: GeodeticObserver, is_geocentric()

Reimplemented in supernovas::GeodeticObserver.

References is_geodetic().

Referenced by supernovas::Frame::Frame(), supernovas::GeodeticObserver::equals(), supernovas::Source::horizontal_track(), and is_geodetic().

◆ moving_on_earth() [1/2]

GeodeticObserver supernovas::Observer::moving_on_earth	(	const Site &	site,
		const EOP &	eop,
		const ScalarVelocity &	horizontal,
		const Angle &	direction,
		const ScalarVelocity &	vertical = ScalarVelocity::stationary() )

static

Instantiates a new observer that is moving relative to Earth's surface, such as an airborne observer.

Parameters

site	the momentary geodetic location of the observer.
eop	Mean (preferably interpolated) Earth Orientation Parameters (EOP) appropriate around the time of observation, such as obtained from the IERS bulletins or data service, or EOP::undefined() to let Frame fetch polar offsets from IERS as needed
horizontal	momentary horizontal speed of moving observer.
direction	azimuthal direction of motion (from North, measured to the East).
vertical	(optional) momentary vertical speed of observer (default: 0).

Since: 1.6

See also: Site::enu_to_itrf()

References supernovas::Validating::is_valid(), and moving_on_earth().

◆ moving_on_earth() [2/2]

GeodeticObserver supernovas::Observer::moving_on_earth	(	const Site &	geodetic,
		const Velocity &	itrs_vel,
		const EOP &	eop = EOP::undefined() )

static

Returns a new observer that is moving, at some velocitym relative to Earth's surface, such as an airborne aircraft or balloon based observatory.

Parameters

geodetic	the momentary geodetic location of the observer.
itrs_vel	the momentary velocity of the observer with respect to the surface (in ITRS).
eop	(optional) Mean (preferably interpolated) Earth Orientation Parameters (EOP) appropriate around the time of observation, such as obtained from the IERS bulletins or data service, or EOP::undefined() to let Frame fetch polar offsets from IERS as needed (default: undefined).

Returns: a new observer instance for the given moving observer.

Since: 1.6

See also: on_earth(), in_earth_orbit(), in_solar_system(), at_geocenter(), at_ssb()

References supernovas::Validating::is_valid(), and moving_on_earth().

Referenced by moving_on_earth(), and moving_on_earth().

◆ on_earth()

GeodeticObserver supernovas::Observer::on_earth	(	const Site &	site,
		const EOP &	eop = EOP::undefined() )

static

Returns a new observer located at a fixed observing site.

Parameters

site	the observing site
eop	(optional) Mean (preferably interpolated) Earth Orientation Parameters (EOP) appropriate around the time of observation, such as obtained from the IERS bulletins or data service, or EOP::undefined() to let Frame fetch polar offsets from IERS as needed (default: undefined).

Returns: a new observer instance for the given observing site.

Since: 1.6

See also: moving_on_earth(), in_earth_orbit(), in_solar_system(), at_geocenter(), at_ssb()

References supernovas::Validating::is_valid(), and on_earth().

Referenced by on_earth(), and supernovas::Site::to_observer().

◆ operator!=()

bool supernovas::Observer::operator!= ( const Observer & other ) const

Checks if two observers differ given standard tolerances associated to their defining components.

Same as !equals().

Parameters

other the other observer

Returns: true if this and the argument describe distinct observing locations, or else false.

Since: 1.7

See also: equals(), operator==()

References equals(), and operator!=().

Referenced by operator!=().

◆ operator==()

bool supernovas::Observer::operator== ( const Observer & other ) const

Checks if two observers are essentially the same within the tolerances associated to their defining components.

Same as equals().

Parameters

other the other observer

Returns: true if both observers effectively describe the same observing location, within tolerances, or else false.

Since: 1.7

See also: equals(), operator!=()

References equals(), and operator==().

Referenced by operator==().

◆ to_string()

std::string supernovas::Observer::to_string ( ) const

virtual

Returns a string representation of this observer.

Returns: a new string with a brief description of this observer.

Since: 1.6

Reimplemented in supernovas::GeocentricObserver, supernovas::GeodeticObserver, and supernovas::SolarSystemObserver.

References _observer, and to_string().

Referenced by to_string().

◆ type()

enum novas_observer_place supernovas::Observer::type ( ) const

Returns the observer type.

Returns: the observer type constant for this observer

Since: 1.6

References _observer, and type().

Referenced by Observer(), and type().

◆ undefined()

const Observer & supernovas::Observer::undefined ( )

static

Returns a reference to a statically defined standard invalid observer.

This invalid observer may be used inside any object that is invalid itself.

Since: 1.6

Returns: a reference to a static standard invalid observer.

References undefined().

Referenced by supernovas::GeocentricObserver::GeocentricObserver(), supernovas::SolarSystemObserver::SolarSystemObserver(), and undefined().

Member Data Documentation

◆ _observer

observer supernovas::Observer::_observer = {}

protected

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Observer()

◆ ~Observer()

Member Function Documentation

◆ _novas_observer()

◆ at_geocenter()

◆ at_ssb()

◆ copy()

◆ equals()

◆ gcrs_position_at()

◆ gcrs_velocity_at()

◆ in_earth_orbit()

◆ in_solar_system()

◆ is_geocentric()

◆ is_geodetic()

◆ moving_on_earth() [1/2]

◆ moving_on_earth() [2/2]

◆ on_earth()

◆ operator!=()

◆ operator==()

◆ to_string()

◆ type()

◆ undefined()

Member Data Documentation

◆ _observer