siderust::BodycentricParams Struct Reference

Parameters for a body-centric coordinate system. More...

#include <siderust/orbital_center.hpp>

Collaboration diagram for siderust::BodycentricParams:

Public Member Functions
	BodycentricParams (const KeplerianOrbit &orb, OrbitReferenceCenter center)
	Creates parameters for a body with the given orbit.
	BodycentricParams ()
	Default: circular 1 AU heliocentric orbit (placeholder).
SiderustBodycentricParams	to_c () const

Static Public Member Functions
static BodycentricParams	heliocentric (const KeplerianOrbit &orb)
	Creates parameters for a body orbiting the Sun.
static BodycentricParams	geocentric (const KeplerianOrbit &orb)
	Creates parameters for a body orbiting Earth.
static BodycentricParams	barycentric (const KeplerianOrbit &orb)
	Creates parameters for a body orbiting the barycenter.

Public Attributes
KeplerianOrbit	orbit
	Keplerian orbital elements of the body.
OrbitReferenceCenter	orbit_center
	Which standard center the orbit is defined relative to.

Detailed Description

Parameters for a body-centric coordinate system.

Specifies the orbital elements of a celestial body and the reference center for those elements. This allows computing a body's position at any Julian date using Keplerian propagation, then using that position as the origin of a coordinate system.

Use Cases

• Satellites: Define L1, L2, L3, L4, L5 positions relative to their parent body (e.g., a halo orbit at the Sun-Earth L2).
• Planets: Compute stellar positions as seen from another planet.
• Moons: Express coordinates relative to a moon's center (e.g., Phobos relative to Mars).

Example: L2 Satellite

// Approximate L2 orbit (1.5M km from Earth on opposite side of Sun)
// In practice, L2 is a quasi-periodic Halo orbit, but we approximate here
KeplerianOrbit l2_approx = {
    1.0,      // semi_major_axis_au (~1 AU from Sun, like Earth)
    0.01,     // eccentricity (small: stable near L2)
    0.0,      // inclination_deg
    0.0,      // lon_ascending_node_deg
    0.0,      // arg_periapsis_deg
    0.0,      // mean_anomaly_deg
    Time<TT, JD>::J2000()
};
BodycentricParams l2_center = BodycentricParams::heliocentric(l2_approx);
 
// Now use l2_center as the reference for body-centric coordinates
// to express Mars's position relative to L2.

Examples

04_all_center_conversions.cpp.

Definition at line 95 of file orbital_center.hpp.

Constructor & Destructor Documentation

BodycentricParams() [1/2]

siderust::BodycentricParams::BodycentricParams ( const KeplerianOrbit &  orb, OrbitReferenceCenter  center  )

inline

Creates parameters for a body with the given orbit.

Parameters

orb	The Keplerian orbital elements.
center	The reference center for the orbit.

Definition at line 108 of file orbital_center.hpp.

BodycentricParams() [2/2]

siderust::BodycentricParams::BodycentricParams ( )

inline

Default: circular 1 AU heliocentric orbit (placeholder).

Definition at line 146 of file orbital_center.hpp.

Referenced by barycentric(), geocentric(), and heliocentric().

Member Function Documentation

barycentric()

static BodycentricParams siderust::BodycentricParams::barycentric ( const KeplerianOrbit &  orb )

inlinestatic

Creates parameters for a body orbiting the barycenter.

Parameters

orb	Barycentric orbital elements.

Returns

BodycentricParams with Barycentric reference.

Definition at line 141 of file orbital_center.hpp.

References siderust::Barycentric, and BodycentricParams().

geocentric()

static BodycentricParams siderust::BodycentricParams::geocentric ( const KeplerianOrbit &  orb )

inlinestatic

Creates parameters for a body orbiting Earth.

Use for artificial satellites, the Moon, etc.

Parameters

orb	Geocentric orbital elements.

Returns

BodycentricParams with Geocentric reference.

Definition at line 131 of file orbital_center.hpp.

References BodycentricParams(), and siderust::Geocentric.

heliocentric()

static BodycentricParams siderust::BodycentricParams::heliocentric ( const KeplerianOrbit &  orb )

inlinestatic

Creates parameters for a body orbiting the Sun.

Most common: planets, asteroids, comets.

Parameters

orb	Heliocentric orbital elements.

Returns

BodycentricParams with Heliocentric reference.

Definition at line 119 of file orbital_center.hpp.

References BodycentricParams(), and siderust::Heliocentric.

to_c()

SiderustBodycentricParams siderust::BodycentricParams::to_c ( ) const

inline

Convert to C FFI struct for passing to siderust_to_bodycentric / siderust_from_bodycentric.

Definition at line 154 of file orbital_center.hpp.

References orbit, orbit_center, and siderust::KeplerianOrbit::to_c().

Referenced by siderust::to_bodycentric(), and siderust::BodycentricPos< F, U >::to_geocentric().

Member Data Documentation

orbit

KeplerianOrbit siderust::BodycentricParams::orbit

Keplerian orbital elements of the body.

Definition at line 97 of file orbital_center.hpp.

Referenced by to_c().

orbit_center

OrbitReferenceCenter siderust::BodycentricParams::orbit_center

Which standard center the orbit is defined relative to.

Definition at line 100 of file orbital_center.hpp.

Referenced by to_c().

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The documentation for this struct was generated from the following file:

• orbital_center.hpp