def from_state_vectors(cls,
pos: TypeVar_NumPy3DArray,
vel: TypeVar_NumPy3DArray,
epoch: TypeVar_DateTime,
name="UNNAMED SATELLITE") -> object:
"""
Creates an instance of Orbit object, using both position and velocity vectors at given epoch
:param pos: vector of position, in GCRS rect frame, at given epoch. units: ([m], [m], [m])
:param vel: vector of velocity, in GCRS rect frame, at given epoch. units: ([m/s], [m/s], [m/s])
:param epoch: corresponding epoch
:type pos: NumPy 3D array
:type vel: NumPy 3D array
:type epoch: Arrow object
:returns: Orbit object
"""
x = np.array([1, 0, 0])
z = np.array([0, 0, 1])
kinetic = np.cross(pos, vel)
kinetic_sq = kinetic.dot(kinetic)
pos_dir = Maths.normalize_vect(pos)
ecc_vec = np.cross(vel, kinetic) / Orbit.MU_EARTH - pos_dir
minusy_ellipse = np.cross(kinetic, ecc_vec) * (-1)
e = np.linalg.norm(ecc_vec) # [1]
ee = e * e
eee = ee * e
eeee = eee * e
i = Maths.angle_vects(z, kinetic) # [rad]
nu = Maths.angle_vects(pos_dir, ecc_vec)
raan = Maths.angle_vects(x, minusy_ellipse) # [rad]
argp = Maths.angle_vects(minusy_ellipse, ecc_vec) # [rad]
a = kinetic_sq / Orbit.MU_EARTH / (1 - e * e)
aaa = a * a * a
n = np.sqrt(Orbit.MU_EARTH / aaa) # [rad/s]
M = (nu - 2 * e * np.sin(nu) +
(3 / 4 * ee + 1 / 8 * eeee) * np.sin(2 * nu) -
1 / 3 * eee * np.sin(3 * nu) + 5 / 32 * eeee * np.sin(4 * nu))
return cls(epoch, e, np.rad2deg(i), np.rad2deg(raan), np.rad2deg(argp),
n * 86400 / Maths.TWOPI, np.rad2deg(M), "idk")
def bbq_check(self, rot_list: list, safe_angle: float):
"""
check for bbq
:param rot_list: list of rotations generated with 'rot_qsw'
:param safe_angle: safe angle for bbq [rad]
"""
bbq_alert = []
for rot in rot_list:
x = rot["gcrs_start_dir"]
y = rot["gcrs_target_dir"]
z = np.cross(x, y)
t = arrow.get(rot["unix_start"])
ts = self.simulation.get_closest_timestamp(t)
s = ts["sun_pos_gcrs"]
s = Maths.normalize_vect(s)
alert = False
angle_norm_plane = Maths.angle_vects(z, s)
if angle_norm_plane > Maths.HALFPI - safe_angle:
if Maths.angle_vects(x, s) < safe_angle or Maths.angle_vects(
y, s) < safe_angle:
alert = True
else:
a = np.cross(z, x)
b = np.cross(y, z)
if np.dot(s, a) > 0 and np.dot(s, b) > 0:
alert = True
if alert:
bbq_alert.append(rot)
return bbq_alert if len(bbq_alert) != 0 else True