def from_classical(attractor, p, ecc, inc, raan, argp, nu,
epoch=J2000):
"""Return `State` object from classical orbital elements.
Parameters
----------
attractor : Body
Main attractor.
p : Quantity
Semilatus rectum.
ecc : Quantity
Eccentricity.
inc : Quantity
Inclination
raan : Quantity
Right ascension of the ascending node.
argp : Quantity
Argument of the pericenter.
nu : Quantity
True anomaly.
epoch : Time, optional
Epoch, default to J2000.
"""
if not check_units((p, ecc, inc, raan, argp, nu),
(u.m, u.one, u.rad, u.rad, u.rad, u.rad)):
raise u.UnitsError("Units must be consistent")
return poliastro.twobody.classical.ClassicalState(
attractor, p, ecc, inc, raan, argp, nu, epoch)
def from_equinoctial(attractor, p, f, g, h, k, L, epoch=J2000):
"""Return `State` object from modified equinoctial elements.
Parameters
----------
attractor : Body
Main attractor.
p : Quantity
Semilatus rectum.
f : Quantity
Second modified equinoctial element.
g : Quantity
Third modified equinoctial element.
h : Quantity
Fourth modified equinoctial element.
k : Quantity
Fifth modified equinoctial element.
L : Quantity
True longitude.
epoch : Time, optional
Epoch, default to J2000.
"""
if not check_units((p, f, g, h, k, L),
(u.m, u.one, u.rad, u.rad, u.rad, u.rad)):
raise u.UnitsError("Units must be consistent")
return poliastro.twobody.equinoctial.ModifiedEquinoctialState(
attractor, p, f, g, h, k, L, epoch)
def parabolic(cls, attractor, p, inc, raan, argp, nu, epoch=J2000):
"""Return `State` corresponding to parabolic orbit.
Parameters
----------
attractor : Body
Main attractor.
p : Quantity
Semilatus rectum or parameter.
inc : Quantity, optional
Inclination.
raan : Quantity
Right ascension of the ascending node.
argp : Quantity
Argument of the pericenter.
nu : Quantity
True anomaly.
epoch: Time, optional
Epoch, default to J2000.
"""
if not check_units((p, inc, raan, argp, nu),
(u.m, u.rad, u.rad, u.rad, u.rad)):
raise u.UnitsError("Units must be consistent")
ecc = 1.0 * u.one
return cls.from_classical(attractor, p, ecc, inc, raan, argp, nu,
epoch)
def circular(cls, attractor, alt,
inc=0 * u.deg, raan=0 * u.deg, arglat=0 * u.deg, epoch=J2000):
"""Return `State` corresponding to a circular orbit.
Parameters
----------
attractor : Body
Main attractor.
alt : Quantity
Altitude over surface.
inc : Quantity, optional
Inclination, default to 0 deg (equatorial orbit).
raan : Quantity, optional
Right ascension of the ascending node, default to 0 deg.
arglat : Quantity, optional
Argument of latitude, default to 0 deg.
epoch: Time, optional
Epoch, default to J2000.
"""
if not check_units((alt, inc, raan, arglat),
(u.m, u.rad, u.rad, u.rad)):
raise u.UnitsError("Units must be consistent")
a = attractor.R + alt
ecc = 0 * u.one
argp = 0 * u.deg
return cls.from_classical(attractor, a, ecc, inc, raan, argp, arglat,
epoch)
def __init__(self, *impulses):
"""Constructor.
Parameters
----------
impulses : list
List of pairs (delta_time, delta_velocity)
Notes
-----
TODO: Fix docstring, \*args convention
"""
self.impulses = impulses
self._dts, self._dvs = zip(*impulses)
u_times = check_units(self._dts, (u.s,))
u_dvs = check_units(self._dvs, (u.m / u.s,))
if not u_times or not u_dvs:
raise u.UnitsError("Units must be consistent")
try:
if not all(len(dv) == 3 for dv in self._dvs):
raise TypeError
except TypeError:
raise ValueError("Delta-V must be three dimensions vectors")
def from_vectors(attractor, r, v, epoch=J2000):
"""Return `State` object from position and velocity vectors.
Parameters
----------
attractor : Body
Main attractor.
r : Quantity
Position vector wrt attractor center.
v : Quantity
Velocity vector.
epoch : Time, optional
Epoch, default to J2000.
"""
if not check_units((r, v), (u.m, u.m / u.s)):
raise u.UnitsError("Units must be consistent")
assert np.any(r.value), "Position vector must be non zero"
return poliastro.twobody.rv.RVState(
attractor, r, v, epoch)
def __init__(self, k, name=None, symbol=None, R=0 * u.km):
"""Constructor.
Parameters
----------
k : Quantity
Standard gravitational parameter
name : str, optional
Name of the body, default to None.
symbol : str, optional
Symbol for the body, default to None.
R : Quantity, optional
Radius of the body, default to 0 km.
"""
if not check_units((k, R), (u.m ** 3 / u.s ** 2, u.m)):
raise u.UnitsError("Units must be consistent")
self.k = k
self.name = name
self.symbol = symbol
self.R = R
