def test_last_time_dependent_frame_between():
"""
Test frame tree structure:
1
/ \
/ \
2 4
/ \
/ \
3 5
The rotations from 3 to 2 and 1 to 4 are time dependent.
All other rotations are constant.
"""
frame_chain = FrameChain()
rotations = [
ConstantRotation(np.array([1, 0, 0, 0]), 2, 1),
TimeDependentRotation(
np.array([1.0 / np.sqrt(2), 0, 0, 1.0 / np.sqrt(2)]),
np.array([1]), 3, 2),
TimeDependentRotation(
np.array([1.0 / np.sqrt(2), 0, 0, 1.0 / np.sqrt(2)]),
np.array([1]), 4, 1),
ConstantRotation(np.array([1.0 / np.sqrt(2), 0, 0, 1.0 / np.sqrt(2)]),
5, 4)
]
frame_chain.add_edge(rotation=rotations[0])
frame_chain.add_edge(rotation=rotations[1])
frame_chain.add_edge(rotation=rotations[2])
frame_chain.add_edge(rotation=rotations[3])
# last frame from node 1 to node 3
s31, d31, _ = frame_chain.last_time_dependent_frame_between(1, 3)
assert s31 == 2
assert d31 == 3
# last frame from node 3 to node 1
s13, d13, _ = frame_chain.last_time_dependent_frame_between(3, 1)
assert s13 == 3
assert d13 == 2
# last frame from node 3 to node 5
s35, d35, _ = frame_chain.last_time_dependent_frame_between(3, 5)
assert s35 == 1
assert d35 == 4
# last frame from node 5 to node 3
s53, d53, _ = frame_chain.last_time_dependent_frame_between(5, 3)
assert s53 == 2
assert d53 == 3
def frame_chain(self):
"""
Construct the initial frame chain using the original sensor_frame_id
obtained from the ikid. Then tack on the ISIS iak rotation.
Returns
-------
: Object
Custom Cassini ALE Frame Chain object for rotation computation and application
"""
if not hasattr(self, '_frame_chain'):
try:
# Call frinfo to check if the ISIS iak has been loaded with the
# additional reference frame. Otherwise, Fail and add it manually
spice.frinfo(self.sensor_frame_id)
self._frame_chain = super().frame_chain
except spice.utils.exceptions.NotFoundError as e:
self._frame_chain = FrameChain.from_spice(sensor_frame=self._original_naif_sensor_frame_id,
target_frame=self.target_frame_id,
center_ephemeris_time=self.center_ephemeris_time,
ephemeris_times=self.ephemeris_time,)
rotation = ConstantRotation([[0, 0, 1, 0]], self.sensor_frame_id, self._original_naif_sensor_frame_id)
self._frame_chain.add_edge(rotation=rotation)
return self._frame_chain
def frame_chain(self):
if not hasattr(self, '_frame_chain'):
self._frame_chain = FrameChain.from_spice(
sensor_frame=self.sensor_frame_id,
target_frame=self.target_frame_id,
center_ephemeris_time=self.center_ephemeris_time,
ephemeris_times=self.ephemeris_time)
return self._frame_chain
def frame_chain(self):
frame_chain = FrameChain()
body_rotation = TimeDependentRotation(
np.array([[0, 0, 0, 1], [0, 0, 0, 1]]), np.array([0, 1]), 100, 1)
frame_chain.add_edge(rotation=body_rotation)
spacecraft_rotation = TimeDependentRotation(
np.array([[0, 0, 0, 1], [0, 0, 0, 1]]), np.array([0, 1]), 1000, 1)
frame_chain.add_edge(rotation=spacecraft_rotation)
sensor_rotation = ConstantRotation(np.array([0, 0, 0, 1]), 1010, 1000)
frame_chain.add_edge(rotation=sensor_rotation)
return frame_chain
def frame_tree(request):
"""
Test frame tree structure:
1
/ \
/ \
2 4
/
/
3
"""
frame_chain = FrameChain()
rotations = [
ConstantRotation(np.array([1, 0, 0, 0]), 2, 1),
ConstantRotation(np.array([1.0 / np.sqrt(2), 0, 0, 1.0 / np.sqrt(2)]),
3, 2),
ConstantRotation(np.array([1.0 / np.sqrt(2), 0, 0, 1.0 / np.sqrt(2)]),
4, 1)
]
frame_chain.add_edge(rotation=rotations[0])
frame_chain.add_edge(rotation=rotations[1])
frame_chain.add_edge(rotation=rotations[2])
return frame_chain, rotations
def frame_chain(self):
"""
Return the root node of the rotation frame tree/chain.
The root node is the J2000 reference frame. The other nodes in the
tree can be accessed via the methods in the FrameNode class.
Returns
-------
FrameNode
The root node of the frame tree. This will always be the J2000 reference frame.
"""
if not hasattr(self, '_frame_chain'):
self._frame_chain = FrameChain.from_isis_tables(
inst_pointing=self.inst_pointing_table,
body_orientation=self.body_orientation_table)
return self._frame_chain
def frame_chain(self):
if not hasattr(self, '_frame_chain'):
nadir = self._props.get('nadir', False)
self._frame_chain = FrameChain.from_spice(
sensor_frame=self.sensor_frame_id,
target_frame=self.target_frame_id,
center_ephemeris_time=self.center_ephemeris_time,
ephemeris_times=self.ephemeris_time,
nadir=nadir)
if nadir:
# Logic for nadir calculation was taken from ISIS3
# SpiceRotation::setEphemerisTimeNadir
rotation = self._frame_chain.compute_rotation(
self.target_frame_id, 1)
p_vec, v_vec, times = self.sensor_position
rotated_positions = rotation.apply_at(p_vec, times)
rotated_velocities = rotation.rotate_velocity_at(
p_vec, v_vec, times)
p_vec = rotated_positions
v_vec = rotated_velocities
velocity_axis = 2
# Get the default line translation with no potential flipping
# from the driver
trans_x = np.array(
list(spice.gdpool('INS{}_ITRANSL'.format(self.ikid), 0,
3)))
if (trans_x[0] < trans_x[1]):
velocity_axis = 1
quats = [
spice.m2q(
spice.twovec(-p_vec[i], 3, v_vec[i], velocity_axis))
for i, time in enumerate(times)
]
quats = np.array(quats)[:, [1, 2, 3, 0]]
rotation = TimeDependentRotation(quats, times, 1,
self.sensor_frame_id)
self._frame_chain.add_edge(rotation)
return self._frame_chain