def test_from_coord_fails_if_no_time_differential():
pos = [30000, 0, 0] * u.km
cartrep = CartesianRepresentation(*pos)
# Method fails if coordinate instance doesn't contain a differential with
# respect to time
with pytest.raises(ValueError) as excinfo:
Orbit.from_coords(Earth, SkyCoord(cartrep))
assert (
"ValueError: Coordinate instance doesn't have a differential with respect to time"
in excinfo.exconly())
def test_from_coord_fails_if_no_time_differential():
pos = [30000, 0, 0] * u.km
cartrep = CartesianRepresentation(*pos)
# Method fails if coordinate instance doesn't contain a differential with
# respect to time
with pytest.raises(ValueError) as excinfo:
Orbit.from_coords(Earth, SkyCoord(cartrep))
assert (
"ValueError: Coordinate instance doesn't have a differential with respect to time"
in excinfo.exconly()
)
def test_from_coord_fails_for_multiple_positions(obstime):
cartdiff = CartesianDifferential([[0, 1, 0], [-0.1, 0.9, 0]] * u.km / u.s,
xyz_axis=1)
cartrep = CartesianRepresentation([[1, 0, 0], [0.9, 0.1, 0]] * u.km,
differentials=cartdiff,
xyz_axis=1)
coords = GCRS(cartrep,
representation_type=CartesianRepresentation,
obstime=obstime)
with pytest.raises(ValueError) as excinfo:
Orbit.from_coords(Earth, coords)
assert (
"ValueError: Coordinate instance must represents exactly 1 position, found: 2"
in excinfo.exconly())
def test_from_coord_fails_for_multiple_positions(obstime):
cartdiff = CartesianDifferential(
[[0, 1, 0], [-0.1, 0.9, 0]] * u.km / u.s, xyz_axis=1
)
cartrep = CartesianRepresentation(
[[1, 0, 0], [0.9, 0.1, 0]] * u.km, differentials=cartdiff, xyz_axis=1
)
coords = GCRS(cartrep, representation_type=CartesianRepresentation, obstime=obstime)
with pytest.raises(ValueError) as excinfo:
Orbit.from_coords(Earth, coords)
assert (
"ValueError: Coordinate instance must represents exactly 1 position, found: 2"
in excinfo.exconly()
)
def test_orbit_creation_using_frame_obj(attractor, frame, obstime):
vel = [0, 2, 0] * u.km / u.s
cartdiff = CartesianDifferential(*vel)
pos = [30000, 0, 0] * u.km
cartrep = CartesianRepresentation(*pos, differentials=cartdiff)
coord = frame(cartrep, obstime=obstime)
o = Orbit.from_coords(attractor, coord)
inertial_frame_at_body_centre = get_frame(attractor,
Planes.EARTH_EQUATOR,
obstime=coord.obstime)
coord_transformed_to_irf = coord.transform_to(
inertial_frame_at_body_centre)
pos_transformed_to_irf = coord_transformed_to_irf.cartesian.xyz
vel_transformed_to_irf = coord_transformed_to_irf.cartesian.differentials[
"s"].d_xyz
assert_quantity_allclose(o.r, pos_transformed_to_irf, atol=1e-5 * u.km)
assert_quantity_allclose(o.v,
vel_transformed_to_irf,
atol=1e-5 * u.km / u.s)
def findstrike(velocity, alt, az):
'''
Parameters
----------
velocity : A `float`
alt: A `float`
az: A `float`
Returns
-------
A `tuple` of two floats
'''
p = sphericalToCartesian(velocity, alt, az)
vx = p[0]
vy = p[1]
vz = p[2]
g = GCRS(x=0 * u.km,
y=0 * u.km,
z=(Earth.R.to(u.km).value + 8.848) * u.km,
v_x=vx * u.km / u.s,
v_y=vy * u.km / u.s,
v_z=vz * u.km / u.s,
representation_type=CartesianRepresentation,
differential_type=CartesianDifferential)
orb = Orbit.from_coords(Earth, g)
tof = timeOfFlight(orb.ecc.value)
orb2 = orb.propagate(tof)
position = orb.r.value
m = CartesianToSpherical(position[0], position[1], position[2])
alt = m[1] * u.rad
az = m[2] * u.rad
altd = alt.to(u.deg)
azd = az.to(u.deg)
return altd, azd
def test_from_coord_if_coord_is_not_of_shape_zero():
pos = [0, 1, 0]
vel = [1, 0, 0]
cartdiff = CartesianDifferential([vel] * u.km / u.s, xyz_axis=1)
cartrep = CartesianRepresentation([pos] * u.km, differentials=cartdiff, xyz_axis=1)
coords = GCRS(cartrep, representation_type=CartesianRepresentation, obstime=J2000)
ss = Orbit.from_coords(Earth, coords)
assert_quantity_allclose(ss.r, pos * u.km, rtol=1e-5)
assert_quantity_allclose(ss.v, vel * u.km / u.s, rtol=1e-5)
def test_from_coord_if_coord_is_not_of_shape_zero():
pos = [0, 1, 0]
vel = [1, 0, 0]
cartdiff = CartesianDifferential([vel] * u.km / u.s, xyz_axis=1)
cartrep = CartesianRepresentation([pos] * u.km, differentials=cartdiff, xyz_axis=1)
coords = GCRS(cartrep, representation_type=CartesianRepresentation, obstime=J2000)
ss = Orbit.from_coords(Earth, coords)
assert_quantity_allclose(ss.r, pos * u.km, rtol=1e-5)
assert_quantity_allclose(ss.v, vel * u.km / u.s, rtol=1e-5)
def test_orbit_creation_using_skycoord(attractor):
vel = [0, 2, 0] * u.km / u.s
cartdiff = CartesianDifferential(*vel)
pos = [30_000, 0, 0] * u.km
cartrep = CartesianRepresentation(*pos, differentials=cartdiff)
coord = SkyCoord(cartrep, frame="icrs")
o = Orbit.from_coords(attractor, coord)
inertial_frame_at_body_centre = get_frame(
attractor, Planes.EARTH_EQUATOR, obstime=coord.obstime
)
coord_transformed_to_irf = coord.transform_to(inertial_frame_at_body_centre)
pos_transformed_to_irf = coord_transformed_to_irf.cartesian.xyz
vel_transformed_to_irf = coord_transformed_to_irf.cartesian.differentials["s"].d_xyz
assert (o.r == pos_transformed_to_irf).all()
assert (o.v == vel_transformed_to_irf).all()
def test_orbit_creation_using_skycoord(attractor):
vel = [0, 2, 0] * u.km / u.s
cartdiff = CartesianDifferential(*vel)
pos = [30000, 0, 0] * u.km
cartrep = CartesianRepresentation(*pos, differentials=cartdiff)
coord = SkyCoord(cartrep, frame="icrs")
o = Orbit.from_coords(attractor, coord)
inertial_frame_at_body_centre = get_frame(
attractor, Planes.EARTH_EQUATOR, obstime=coord.obstime
)
coord_transformed_to_irf = coord.transform_to(inertial_frame_at_body_centre)
pos_transformed_to_irf = coord_transformed_to_irf.cartesian.xyz
vel_transformed_to_irf = coord_transformed_to_irf.cartesian.differentials["s"].d_xyz
assert (o.r == pos_transformed_to_irf).all()
assert (o.v == vel_transformed_to_irf).all()
def test_orbit_creation_using_frame_obj(attractor, frame, obstime):
vel = [0, 2, 0] * u.km / u.s
cartdiff = CartesianDifferential(*vel)
pos = [30000, 0, 0] * u.km
cartrep = CartesianRepresentation(*pos, differentials=cartdiff)
coord = frame(cartrep, obstime=obstime)
o = Orbit.from_coords(attractor, coord)
inertial_frame_at_body_centre = get_frame(
attractor, Planes.EARTH_EQUATOR, obstime=coord.obstime
)
coord_transformed_to_irf = coord.transform_to(inertial_frame_at_body_centre)
pos_transformed_to_irf = coord_transformed_to_irf.cartesian.xyz
vel_transformed_to_irf = coord_transformed_to_irf.cartesian.differentials["s"].d_xyz
assert_quantity_allclose(o.r, pos_transformed_to_irf, atol=1e-5 * u.km)
assert_quantity_allclose(o.v, vel_transformed_to_irf, atol=1e-5 * u.km / u.s)
