Admin tsn le 27 novembre 2025 à 09:34

2025-11-27T09:34:46Z

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	* A <code>PVCoordinateProvider</code>: retrieve position and velocity at any time		* A <code>PVCoordinateProvider</code>: retrieve position and velocity at any time

	=== ~~Body shapes~~ ===		==== BodyShape====
	The ~~one-axis ellipsoid~~ is ~~a good approximate model~~ for ~~most planet-size~~ and ~~larger natural bodies~~. ~~It is~~ the ~~equilibrium~~ shape ~~reached~~ by a ~~fluid~~ body ~~under its own gravity field when it rotates~~. The ~~symmetry axis~~ is the ~~rotation or polar axis~~.
			The BodyShape interface carries servals features common to body shapes such as its name, frame, intersection point computation, distance to a line, closest point computation, body point transformation.
			A couple of getter/setter allows to configure the LLHCoordinatesSystem associated to the shape, which can be ELLIPSODETIC, BODYCENTRIC_RADIAL or BODYCENTRIC_NORMAL. This coordinates system is used for instance by closest point computation or body point transformation.
			The interface extends the PVCoordinatesProvider and ApparentRadiusProvider interfaces. The first carry the service to determine the PVCoordinates of the body at any date and the second describes two related features:
			* Compute the apparent radius of the occulting body from the spacecraft (observer) position. Given a plane containing the spacecraft position, the center of the occulting body (the body shape) and the center of the occulted body, and given a line contained within this plane, passing by the spacecraft position and tangent to the mesh of the occulting body, the apparent radius corresponds to the length of the line starting from the center of the occulting body, perpendicular to the first given line and ending at the intersection of the two lines.
			* Compute the apparent radius in a plane containing the spacecraft position, the center of the occulting body and a specified direction instead of the occulted body position. The rest of the behavior stays identical.
			Note: The apparent radius is computed in one direction from the frame origin of the body to the perpendicular tangent line. In case of dissymmetric shape, this definition it might introduce some limitations as the radius computed in the other direction would be different.

	==== OneAxisEllipsoid ====		==== OneAxisEllipsoid ====

	This type is used to represent the shape of a planet. One very useful implementation represents an ellipsoid (OneAxisEllipsoid). It is constructed from an equatorial radius, a flattening coefficient, and a reference frame that will be used to localize Geodetic points on the shape.		This type is used to represent the shape of a planet. One very useful implementation represents an ellipsoid (OneAxisEllipsoid). It is constructed from an equatorial radius, a flattening coefficient, and a reference frame that will be used to localize Geodetic points on the shape.

			The one-axis ellipsoid is a good approximate model for most planet-size and larger natural bodies. It is the equilibrium shape reached by a fluid body under its own gravity field when it rotates. The symmetry axis is the rotation or polar axis.

	It could be interesting to obtain the intersection point of a line from the satellite to the surface of the body for a given altitude. To that purpose, one can use the method getIntersectionPoint(Line, Vector3D, Frame, AbsoluteDate, double) of the interface BodyShape.		It could be interesting to obtain the intersection point of a line from the satellite to the surface of the body for a given altitude. To that purpose, one can use the method getIntersectionPoint(Line, Vector3D, Frame, AbsoluteDate, double) of the interface BodyShape.
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	Note: The ThreeAxisEllipsoid class shares many features with the OneAxisEllipsoid and allows to define an ellipsoid fully defined by its three axis radius (along the directions (0, 0, 1) ; (0, 1, 0) ; (0, 0, 1)).		Note: The ThreeAxisEllipsoid class shares many features with the OneAxisEllipsoid and allows to define an ellipsoid fully defined by its three axis radius (along the directions (0, 0, 1) ; (0, 1, 0) ; (0, 0, 1)).

	~~==== BodyShape and OneAxisEllipsoid ====~~		OneAxisEllipsoid extends the AbstractEllipsoidBodyShape class (also extended by ThreeAxisEllipsoid) and AbstractEllipsoidBodyShape implements the EllipsoidBodyShape interface, which extends the StarConvexBodyShape interface, which, at its turn, extends the BodyShape interface (already introduced).

	OneAxisEllipsoid extends the AbstractEllipsoidBodyShape class (also extended by ThreeAxisEllipsoid) and AbstractEllipsoidBodyShape implements the EllipsoidBodyShape interface, which extends the StarConvexBodyShape interface, which, at its turn, extends the BodyShape interface.
	~~See the [MIS_SENSORS_PatriusBodySpheroid specific page] for more details~~.

	==== Facet celestial body ====		==== Facet celestial body ====
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	* <code>getIntersection(Line, Vector3D, Frame, AbsoluteDate)</code> and similar which return an <code>Intersection</code> object.This object contains the intersection point as well as the <code>Triangle</code> containing the intersection point. This method is recursive and is in O(log(n)).		* <code>getIntersection(Line, Vector3D, Frame, AbsoluteDate)</code> and similar which return an <code>Intersection</code> object.This object contains the intersection point as well as the <code>Triangle</code> containing the intersection point. This method is recursive and is in O(log(n)).
	* <code>buildPoint(LLHCoordinatesSystem, double, double, double, String)</code> and similar which return the facet point associated to the specified corrinates in the given LLH coordinates system.		* <code>buildPoint(LLHCoordinatesSystem, double, double, double, String)</code> and similar which return the facet point associated to the specified corrinates in the given LLH coordinates system.
	* <code>getApparentRadius()</code> methods which provides the local radius ~~from~~ an ~~object and~~ an occulted body using an approximate iterative algorithm. This method is ~~to be~~ used ~~only~~ by ~~<code>~~EclipseDetector~~</code>~~.		* <code>getApparentRadius</code> / <code>getApparentRadiusDirection</code> methods which provides the local radius of the body shape seen by an observer in the direction of an occulted body or a specified direction using an approximate iterative algorithm. This method is used by EclipseDetector for instance.
	* <code>resize(MarginType, double)</code> method which returns a resized body shape.		* <code>resize(MarginType, double)</code> method which returns a resized body shape.
	* <code>closestPointTo</code> methods which return the two closest points between the line given in input and the current facet body shape. One of the two points belongs to the line, the other to the facet body shape.		* <code>closestPointTo</code> methods which return the two closest points between the line given in input and the current facet body shape. One of the two points belongs to the line, the other to the facet body shape.
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	! scope="col"\| Summary		! scope="col"\| Summary
	! scope="col"\| Javadoc		! scope="col"\| Javadoc
			\|-
			\|'''ApparentRadiusProvider'''
			\|Interface representing apparent radius providers.
			\|[{{JavaDoc4.17}}/fr/cnes/sirius/patrius/bodies/ApparentRadiusProvider.html ...]
	\|-		\|-
	\|'''BodyShape'''		\|'''BodyShape'''
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	\|Modeling of a one-axis ellipsoid.		\|Modeling of a one-axis ellipsoid.
	\|[{{JavaDoc4.17}}/fr/cnes/sirius/patrius/bodies/OneAxisEllipsoid.html ...]		\|[{{JavaDoc4.17}}/fr/cnes/sirius/patrius/bodies/OneAxisEllipsoid.html ...]
			\|-
			\|'''ThreeAxisEllipsoid'''
			\|Modeling of a tri-axis ellipsoid.
			\|[{{JavaDoc4.17}}/fr/cnes/sirius/patrius/bodies/ThreeAxisEllipsoid.html ...]
	\|-		\|-
	\|'''MeeusSun'''		\|'''MeeusSun'''

Admin tsn : Page créée avec « NOTOC == Introduction == === Scope === The celestial bodies are described by their main features : position and geometry. The positions are ephemeris that must be loaded from models, the geometries are created as one axis ellipsoids or facet bodies. The package provides a factory able to create any celestial body of the solar system. === Javadoc === The classes for bodies description are available in the package `bodies` of Patrius. {| class="wi... »

2025-11-26T13:50:47Z

Page créée avec « __NOTOC__ == Introduction == === Scope === The celestial bodies are described by their main features : position and geometry. The positions are ephemeris that must be loaded from models, the geometries are created as one axis ellipsoids or facet bodies. The package provides a factory able to create any celestial body of the solar system. === Javadoc === The classes for bodies description are available in the package <code>bodies</code> of Patrius. {| class="wi... »

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User Manual 4.17 Celestial bodies - Historique des versions

Admin tsn le 27 novembre 2025 à 09:34