Gravity.hpp File Reference

Different Gravity Models. More...

Go to the source code of this file.

Enumerations
enum class	NAV::GravitationModel : int {   None ,   WGS84 ,   WGS84_Skydel ,   Somigliana ,   EGM96 ,   COUNT }
	Available Gravitation Models. More...

Functions
bool	NAV::ComboGravitationModel (const char *label, GravitationModel &gravitationModel)
	Shows a ComboBox to select the gravitation model.
template<typename Derived >
Eigen::Vector3< typename Derived::Scalar >	NAV::n_calcGravitation (const Eigen::MatrixBase< Derived > &lla_position, GravitationModel gravitationModel=GravitationModel::EGM96)
	Calculates the gravitation (acceleration due to mass attraction of the Earth)
template<typename Derived >
Eigen::Vector3< typename Derived::Scalar >	NAV::n_calcGravitation_EGM96 (const Eigen::MatrixBase< Derived > &lla_position, size_t ndegree=10)
	Calculates the gravitation (acceleration due to mass attraction of the Earth) at the WGS84 reference ellipsoid using the EGM96 spherical harmonic model (up to order 10)
template<typename Scalar , typename = std::enable_if_t<std::is_floating_point_v<Scalar>>>
Eigen::Vector3< Scalar >	NAV::n_calcGravitation_SomiglianaAltitude (const Scalar &latitude, const Scalar &altitude)
	Calculates the gravitation (acceleration due to mass attraction of the Earth) at the WGS84 reference ellipsoid using the Somigliana model and makes corrections for altitude.
template<typename Scalar , typename = std::enable_if_t<std::is_floating_point_v<Scalar>>>
Eigen::Vector3< Scalar >	NAV::n_calcGravitation_WGS84 (const Scalar &latitude, const Scalar &altitude)
	Calculates the gravitation (acceleration due to mass attraction of the Earth) at the WGS84 reference ellipsoid using gravity as derived from the gravity potential.
template<typename Scalar , typename = std::enable_if_t<std::is_floating_point_v<Scalar>>>
Eigen::Vector3< Scalar >	NAV::n_calcGravitation_WGS84_Skydel (const Scalar &latitude, const Scalar &altitude)
	Calculates the gravitation (acceleration due to mass attraction of the Earth) at the WGS84 reference ellipsoid using gravity as derived from the gravity potential. However, the north component of the centrifugal acceleration is neglected in order to match the implementation of Skydel's 'ImuPlugin'.
const char *	NAV::to_string (GravitationModel gravitationModel)
	Converts the enum to a string.

Detailed Description

Different Gravity Models.

Author

T. Topp (topp@.nosp@m.ins..nosp@m.uni-s.nosp@m.tutt.nosp@m.gart..nosp@m.de)

M. Maier (marce.nosp@m.l.ma.nosp@m.ier@i.nosp@m.ns.u.nosp@m.ni-st.nosp@m.uttg.nosp@m.art.d.nosp@m.e)

Date

2020-09-15

Enumeration Type Documentation

GravitationModel

enum class NAV::GravitationModel : int

strong

Available Gravitation Models.

Enumerator
None	Gravity Model turned off.
WGS84	World Geodetic System 1984.
WGS84_Skydel	World Geodetic System 1984 implemented by the Skydel Simulator // FIXME: Remove after Skydel uses the same as Instinct.
Somigliana	Somigliana gravity model.
EGM96	Earth Gravitational Model 1996.
COUNT	Amount of items in the enum.

Function Documentation

ComboGravitationModel()

bool NAV::ComboGravitationModel	(	const char *	label,
		GravitationModel &	gravitationModel )

Shows a ComboBox to select the gravitation model.

Parameters

[in]	label	Label to show beside the combo box. This has to be a unique id for ImGui.
[in]	gravitationModel	Reference to the gravitation model to select

n_calcGravitation()

template<typename Derived >

Eigen::Vector3< typename Derived::Scalar > NAV::n_calcGravitation	(	const Eigen::MatrixBase< Derived > &	lla_position,
		GravitationModel	gravitationModel = GravitationModel::EGM96 )

Calculates the gravitation (acceleration due to mass attraction of the Earth)

Parameters

[in]	lla_position	[ϕ, λ, h] Latitude, Longitude, Altitude in [rad, rad, m]
[in]	gravitationModel	Gravitation model to use

Returns

Gravitation vector in local-navigation frame coordinates in [m/s^2]

n_calcGravitation_EGM96()

template<typename Derived >

Eigen::Vector3< typename Derived::Scalar > NAV::n_calcGravitation_EGM96	(	const Eigen::MatrixBase< Derived > &	lla_position,
		size_t	ndegree = 10 )

Calculates the gravitation (acceleration due to mass attraction of the Earth) at the WGS84 reference ellipsoid using the EGM96 spherical harmonic model (up to order 10)

Parameters

[in]	lla_position	[ϕ, λ, h] Latitude, Longitude, Altitude in [rad, rad, m]
[in]	ndegree	Degree of the EGM96 (1 <= ndegree <= 10)

Returns

Gravitation vector in local-navigation frame coordinates in [m/s^2]

Note

See Groves (2013) Chapter 2.4.3 and 'GUT User Guide' (2018) Chapter 7.4

n_calcGravitation_SomiglianaAltitude()

template<typename Scalar , typename = std::enable_if_t<std::is_floating_point_v<Scalar>>>

Eigen::Vector3< Scalar > NAV::n_calcGravitation_SomiglianaAltitude	(	const Scalar &	latitude,
		const Scalar &	altitude )

Calculates the gravitation (acceleration due to mass attraction of the Earth) at the WGS84 reference ellipsoid using the Somigliana model and makes corrections for altitude.

Parameters

[in]	latitude	Latitude in [rad]
[in]	altitude	Altitude in [m]

Returns

Gravitation vector in local-navigation frame coordinates in [m/s^2]

Note

See S. Gleason (2009) - GNSS Applications and Methods (Chapter 6.2.3.2 - eq. 6.16)

n_calcGravitation_WGS84()

template<typename Scalar , typename = std::enable_if_t<std::is_floating_point_v<Scalar>>>

Eigen::Vector3< Scalar > NAV::n_calcGravitation_WGS84	(	const Scalar &	latitude,
		const Scalar &	altitude )

Calculates the gravitation (acceleration due to mass attraction of the Earth) at the WGS84 reference ellipsoid using gravity as derived from the gravity potential.

Parameters

[in]	latitude	Latitude in [rad]
[in]	altitude	Altitude in [m]

Returns

Gravitation vector in local-navigation frame coordinates in [m/s^2]

Note

See 'INS-Projects/INSTINCT/SpecificLiterature/GravityPotentialWGS84' in NC folder (eq. (3) derived after 'r')

n_calcGravitation_WGS84_Skydel()

template<typename Scalar , typename = std::enable_if_t<std::is_floating_point_v<Scalar>>>

Eigen::Vector3< Scalar > NAV::n_calcGravitation_WGS84_Skydel	(	const Scalar &	latitude,
		const Scalar &	altitude )

Calculates the gravitation (acceleration due to mass attraction of the Earth) at the WGS84 reference ellipsoid using gravity as derived from the gravity potential. However, the north component of the centrifugal acceleration is neglected in order to match the implementation of Skydel's 'ImuPlugin'.

Parameters

[in]	latitude	Latitude in [rad]
[in]	altitude	Altitude in [m]

Returns

Gravitation vector in local-navigation frame coordinates in [m/s^2]

Note

See Skydel API plug-in 'skydel_plugin/source/library/inertial_math/Sources/source/gravity.cpp'

to_string()

const char * NAV::to_string

(

GravitationModel

gravitationModel

)

Converts the enum to a string.

Parameters

[in]

gravitationModel

Enum value to convert into text

Returns

String representation of the enum