Consists of methods dealing with Earth geographic coordinates and locations. More...

#include "geographic-positions.h"

Collaboration diagram for ns3::GeographicPositions:

Public Types
enum	EarthSpheroidType { SPHERE , GRS80 , WGS84 }
	The possible Earth spheroid models. . More...

Static Public Member Functions
static Vector	CartesianToGeographicCoordinates (Vector pos, EarthSpheroidType sphType)
	Inverse of GeographicToCartesianCoordinates using [1].

static Vector	GeographicToCartesianCoordinates (double latitude, double longitude, double altitude, EarthSpheroidType sphType)
	Converts earth geographic/geodetic coordinates (latitude and longitude in degrees) with a given altitude above earth's surface (in meters) to Earth Centered Earth Fixed (ECEF) Cartesian coordinates (x, y, z in meters), where origin (0, 0, 0) is the center of the earth.

static Vector	GeographicToTopocentricCoordinates (Vector pos, Vector refPoint, EarthSpheroidType sphType)
	Conversion from geographic to topocentric coordinates.

static std::tuple< double, double, double >	GetRadiusEccentFlat (EarthSpheroidType type)

static std::list< Vector >	RandCartesianPointsAroundGeographicPoint (double originLatitude, double originLongitude, double maxAltitude, int numPoints, double maxDistFromOrigin, Ptr< UniformRandomVariable > uniRand)
	Generates uniformly distributed random points (in ECEF Cartesian coordinates) within a given altitude above earth's surface centered around a given origin point (on earth's surface, in geographic/geodetic coordinates) within a given distance radius (using arc length of earth's surface, not pythagorean distance).

static Vector	TopocentricToGeographicCoordinates (Vector pos, Vector refPoint, EarthSpheroidType sphType)
	Conversion from topocentric to geographic.

Static Public Attributes
static constexpr double	EARTH_GRS80_ECCENTRICITY = 0.0818191910428158
	Earth's first eccentricity as defined by GRS80 https://en.wikipedia.org/wiki/Geodetic_Reference_System_1980.

static constexpr double	EARTH_GRS80_FLATTENING = 0.003352810681183637418
	Earth's first flattening as defined by GRS80 https://en.wikipedia.org/wiki/Geodetic_Reference_System_1980.

static constexpr double	EARTH_SEMIMAJOR_AXIS = 6378137
	<Earth's semi-major axis in meters as defined by both GRS80 and WGS84 https://en.wikipedia.org/wiki/World_Geodetic_System

static constexpr double	EARTH_SPHERE_ECCENTRICITY = 0
	Earth's eccentricity if modeled as a perfect sphere.

static constexpr double	EARTH_SPHERE_FLATTENING = 0
	Earth's flattening if modeled as a perfect sphere.

static constexpr double	EARTH_SPHERE_RADIUS = 6371e3
	Spheroid model to use for earth: perfect sphere (SPHERE), Geodetic Reference System 1980 (GRS80), or World Geodetic System 1984 (WGS84)

static constexpr double	EARTH_WGS84_ECCENTRICITY = 0.0818191908426215
	Earth's first eccentricity as defined by https://en.wikipedia.org/wiki/World_Geodetic_System#WGS84.

static constexpr double	EARTH_WGS84_FLATTENING = 0.00335281
	Earth's first flattening as defined by WGS84 https://en.wikipedia.org/wiki/World_Geodetic_System#WGS84.

Detailed Description

Consists of methods dealing with Earth geographic coordinates and locations.

Definition at line 34 of file geographic-positions.h.

Member Enumeration Documentation

◆ EarthSpheroidType

enum ns3::GeographicPositions::EarthSpheroidType

The possible Earth spheroid models. .

Enumerator
SPHERE
GRS80
WGS84

Definition at line 79 of file geographic-positions.h.

Member Function Documentation

◆ CartesianToGeographicCoordinates()

Vector ns3::GeographicPositions::CartesianToGeographicCoordinates	(	Vector	pos,
		EarthSpheroidType	sphType
	)

static

Inverse of GeographicToCartesianCoordinates using [1].

This function iteratively converts cartesian (ECEF) coordinates to geographic coordinates. The residual delta is 1 m, which is approximately 1 / 30 arc seconds or 9.26e-6 deg.

Parameters

pos	a vector representing the Cartesian coordinates (x, y, z referenced in meters) of the point (origin (0, 0, 0) is center of earth)
sphType	earth spheroid model to use for conversion

Returns: Vector position where x = latitude (deg), y = longitude (deg), z = altitude above the ellipsoid (m)

[1] "Ellipsoidal and Cartesian Coordinates Conversion", Navipedia, European Space Agency, Jul 8, 2019. https://gssc.esa.int/navipedia/index.php/Ellipsoidal_and_Cartesian_Coordinates_Conversion

Definition at line 73 of file geographic-positions.cc.

References ns3::CalculateDistance(), ns3::DegreesToRadians(), GetRadiusEccentFlat(), NS_ASSERT_MSG, NS_LOG_FUNCTION, and ns3::RadiansToDegrees().

Referenced by CartesianToGeoTestCase::DoRun(), and ns3::GeocentricConstantPositionMobilityModel::DoSetGeocentricPosition().

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◆ GeographicToCartesianCoordinates()

Vector ns3::GeographicPositions::GeographicToCartesianCoordinates	(	double	latitude,
		double	longitude,
		double	altitude,
		EarthSpheroidType	sphType
	)

static

Converts earth geographic/geodetic coordinates (latitude and longitude in degrees) with a given altitude above earth's surface (in meters) to Earth Centered Earth Fixed (ECEF) Cartesian coordinates (x, y, z in meters), where origin (0, 0, 0) is the center of the earth.

Parameters

latitude	earth-referenced latitude (in degrees) of the point
longitude	earth-referenced longitude (in degrees) of the point
altitude	height of the point (in meters) above earth's surface
sphType	earth spheroid model to use for conversion

Returns: a vector representing the Cartesian coordinates (x, y, z referenced in meters) of the point (origin (0, 0, 0) is center of earth)

Definition at line 52 of file geographic-positions.cc.

References ns3::DegreesToRadians(), GetRadiusEccentFlat(), and NS_LOG_FUNCTION_NOARGS.

Referenced by ns3::GeocentricConstantPositionMobilityModel::DoGetDistanceFrom(), ns3::GeocentricConstantPositionMobilityModel::DoGetGeocentricPosition(), GeoToCartesianTestCase::DoRun(), CartesianToGeoTestCase::DoRun(), RandCartAroundGeoTestCase::DoRun(), and RandCartesianPointsAroundGeographicPoint().

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◆ GeographicToTopocentricCoordinates()

Vector ns3::GeographicPositions::GeographicToTopocentricCoordinates	(	Vector	pos,
		Vector	refPoint,
		EarthSpheroidType	sphType
	)

static

Conversion from geographic to topocentric coordinates.

Conversion formulas taken from [1, Sec. 4.1.3 "Geographic/topocentric conversions"]. [1] IOGP. Geomatics guidance note 7, part 2: coordinate conversions & transformations including formulas. IOGP Publication 373-7-2, International Association For Oil And Gas Producers, Sep. 2019 https://www.iogp.org/bookstore/product/coordinate-conversions-and-transformation-including-formulas/

Parameters

pos	a vector representing the Geographic coordinates (latitude, longitude, altitude) in degrees (lat/lon) and meters (altitude).
refPoint	a vector representing the reference point (latitude, longitude, altitude) in degrees (lat/lon) and meters (altitude). Default is (0,0,0)
sphType	earth spheroid model to use for conversion

Returns: Vector position in meters and using planar Cartesian coordinates, i.e., ns-3's defaults

Definition at line 130 of file geographic-positions.cc.

References ns3::DegreesToRadians(), GetRadiusEccentFlat(), and NS_LOG_FUNCTION.

Referenced by ns3::GeocentricConstantPositionMobilityModel::DoGetPosition(), and GeoToAndFromTopocentricTestCase::TestReferencePoint().

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◆ GetRadiusEccentFlat()

std::tuple< double, double, double > ns3::GeographicPositions::GetRadiusEccentFlat ( EarthSpheroidType type )

static

Parameters

type	the type of model which is used to model the Earth

Returns: the corresponding radius (in meters), first eccentricity and first flattening values

Definition at line 299 of file geographic-positions.cc.

References EARTH_GRS80_ECCENTRICITY, EARTH_GRS80_FLATTENING, EARTH_SEMIMAJOR_AXIS, EARTH_SPHERE_ECCENTRICITY, EARTH_SPHERE_FLATTENING, EARTH_SPHERE_RADIUS, EARTH_WGS84_ECCENTRICITY, EARTH_WGS84_FLATTENING, GRS80, NS_FATAL_ERROR, SPHERE, and WGS84.

Referenced by CartesianToGeographicCoordinates(), GeographicToCartesianCoordinates(), GeographicToTopocentricCoordinates(), and TopocentricToGeographicCoordinates().

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◆ RandCartesianPointsAroundGeographicPoint()

std::list< Vector > ns3::GeographicPositions::RandCartesianPointsAroundGeographicPoint	(	double	originLatitude,
		double	originLongitude,
		double	maxAltitude,
		int	numPoints,
		double	maxDistFromOrigin,
		Ptr< UniformRandomVariable >	uniRand
	)

static

Generates uniformly distributed random points (in ECEF Cartesian coordinates) within a given altitude above earth's surface centered around a given origin point (on earth's surface, in geographic/geodetic coordinates) within a given distance radius (using arc length of earth's surface, not pythagorean distance).

Distance radius is measured as if all generated points are on earth's surface (with altitude = 0). Assumes earth is a perfect sphere.

Parameters

originLatitude	origin point latitude in degrees
originLongitude	origin point longitude in degrees
maxAltitude	maximum altitude in meters above earth's surface with which random points can be generated
numPoints	number of points to generate
maxDistFromOrigin	max distance in meters from origin with which random transmitters can be generated (all transmitters are less than or equal to this distance from the origin, relative to points being on earth's surface)
uniRand	pointer to the uniform random variable to use for random location and altitude generation

Returns: a list containing the vectors (x, y, z location referenced in meters from origin at center of earth) of each point generated

Definition at line 208 of file geographic-positions.cc.

References ns3::DegreesToRadians(), EARTH_SPHERE_RADIUS, GeographicToCartesianCoordinates(), NS_LOG_FUNCTION_NOARGS, NS_LOG_WARN, ns3::RadiansToDegrees(), and SPHERE.

Referenced by ns3::TvSpectrumTransmitterHelper::CreateRegionalTvTransmitters(), and RandCartAroundGeoTestCase::DoRun().

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◆ TopocentricToGeographicCoordinates()

Vector ns3::GeographicPositions::TopocentricToGeographicCoordinates	(	Vector	pos,
		Vector	refPoint,
		EarthSpheroidType	sphType
	)

static

Conversion from topocentric to geographic.

Conversion formulas taken from [1, Sec. 4.1.3 "Geographic/topocentric conversions"]. [1] IOGP. Geomatics guidance note 7, part 2: coordinate conversions & transformations including formulas. IOGP Publication 373-7-2, International Association For Oil And Gas Producers, Sep. 2019 https://www.iogp.org/bookstore/product/coordinate-conversions-and-transformation-including-formulas/

Parameters

pos	a vector representing the topocentric coordinates (u, v, w) in meters, which represent the cartesian coordinates along the xEast, yNorth and zUp axes, respectively..
refPoint	a vector representing the reference point (latitude, longitude, altitude) in degrees (lat/lon) and meters (altitude). Default is (0,0,0)
sphType	earth spheroid model to use for conversion