💿🐜 Antkeeper source code
https://antkeeper.com
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131 lines
4.8 KiB
131 lines
4.8 KiB
/*
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* Copyright (C) 2021 Christopher J. Howard
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*
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* This file is part of Antkeeper source code.
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*
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* Antkeeper source code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Antkeeper source code is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef ANTKEEPER_PHYSICS_ORBIT_FRAMES_HPP
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#define ANTKEEPER_PHYSICS_ORBIT_FRAMES_HPP
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#include "physics/frame.hpp"
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namespace physics {
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namespace orbit {
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/// Inertial right-handed coordinate system
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namespace inertial {
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/**
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* Constucts a reference frame which transforms coordinates from inertial space into perifocal space.
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*
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* @param focus Cartesian coordinates of the focus of the orbit, in the parent space.
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* @param raan Right ascension of the ascending node (OMEGA), in radians.
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* @param i Orbital inclination (i), in radians.
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* @param w Argument of periapsis (omega), in radians.
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* @return Perifocal frame.
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*/
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template <typename T>
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physics::frame<T> to_perifocal(const math::vector3<T>& focus, T raan, T i, T w)
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{
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const math::quaternion<T> rotation = math::normalize
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(
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math::quaternion<T>::rotate_z(raan) *
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math::quaternion<T>::rotate_x(i) *
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math::quaternion<T>::rotate_z(w)
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);
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return physics::frame<T>{focus, rotation}.inverse();
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}
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/**
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* Constructs a reference frame which transforms coordinates from inertial space to body-centered inertial space.
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*
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* @param r Cartesian position vector (r) of the center of the body, in inertial space.
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* @param i Orbital inclination (i), in radians.
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* @param axial_tilt Angle between the body's rotational axis and its orbital axis, in radians.
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* @return Body-centered inertial frame.
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*/
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template <typename T>
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physics::frame<T> to_bci(const math::vector3<T>& r, T i, T axial_tilt)
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{
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return physics::frame<T>{r, math::quaternion<T>::rotate_x(-axial_tilt - i)}.inverse();
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}
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/**
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* Constructs a reference frame which transforms coordinates from inertial space to body-centered, body-fixed space.
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*
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* @param r Cartesian position vector (r) of the center of the body, in inertial space.
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* @param i Orbital inclination (i), in radians.
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* @param axial_tilt Angle between the orbiting body's rotational axis and its orbital axis, in radians.
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* @param axial_rotation Angle of rotation about the orbiting body's rotational axis, in radians.
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*/
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template <typename T>
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frame<T> to_bcbf(const math::vector3<T>& r, T i, T axial_tilt, T axial_rotation)
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{
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const math::quaternion<T> rotation = math::normalize
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(
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math::quaternion<T>::rotate_x(-axial_tilt - i) *
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math::quaternion<T>::rotate_z(axial_rotation)
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);
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return physics::frame<T>{r, rotation}.inverse();
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}
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} // namespace inertial
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/// Perifocal right-handed coordinate system in which the x-axis points toward the periapsis of the orbit, the y-axis has a true anomaly of 90 degrees past the periapsis, and the z-axis is the angular momentum vector, which is orthogonal to the orbital plane.
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namespace perifocal {
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} // namespace perifocal
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/// Non-inertial body-centered, body-fixed right-handed coordinate system. The x-axis is orthogonal to the intersection of the prime meridian and the equator. The z-axis points toward the positive pole. The y-axis is right-hand orthogonal to the xz-plane.
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namespace bcbf {
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/**
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* Constructs a reference frame which transforms coordinates from BCBF space to topocentric space.
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*
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* @param distance Radial distance of the observer from the center of the body.
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* @param latitude Latitude of the observer, in radians.
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* @param longitude Longitude of the obserer, in radians.
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* @return Topocentric frame.
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*/
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template <typename T>
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physics::frame<T> to_topocentric(T distance, T latitude, T longitude)
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{
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const math::vector3<T> translation = {T(0), T(0), distance};
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const math::quaternion<T> rotation = math::normalize
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(
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math::quaternion<T>::rotate_z(longitude) *
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math::quaternion<T>::rotate_y(math::half_pi<T> - latitude)
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);
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return physics::frame<T>{rotation * translation, rotation}.inverse();
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}
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} // namespace bcbf
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/// Non-inertial topocentric right-handed coordinate system. Topocentric frames are constructed as south-east-zenith (SEZ) frames; the x-axis points south, the y-axis points east, and the z-axis points toward the zenith (orthogonal to reference spheroid).
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namespace topocentric {
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} // namespace topocentric
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} // namespace orbit
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} // namespace physics
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#endif // ANTKEEPER_PHYSICS_ORBIT_FRAMES_HPP
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