def calculated_field_angles(calc_source,
attitude,
sat,
t,
double_telescope=False):
"""
| Ref. Paper [LUDW2011]_ eq. [12]-[13]
| Return field angles according to Lindegren eq. 12. See :meth:`compute_field_angles`
:param source: [Calc_source]
:param attitude: [quaternion] attitude at time t
:param sat: [Satellite]
:param t: [float] time at which we want the angles
:param double_telescope: [bool] If true, uses the model with two telescopes
:returns:
* eta: along-scan field angle (== phi if double_telescope = False)
* zeta: across-scan field angle
"""
alpha, delta, parallax, mu_alpha, mu_delta = calc_source.s_params[:]
params = np.array(
[alpha, delta, parallax, mu_alpha, mu_delta, calc_source.mu_radial])
Cu = compute_topocentric_direction(params, sat, t) # u in CoMRS frame
Su = ft.lmn_to_xyz(attitude, Cu) # u in SRS frame
eta, zeta = compute_field_angles(Su, double_telescope)
return eta, zeta
def compute_stuff_for_source(self, s):
raise ValueError('This function is not complete')
alpha, delta, parallax, mu_alpha, mu_delta = calc_source.s_params[:]
params = np.array([alpha, delta, parallax, mu_alpha, mu_delta, calc_source.mu_radial])
Cu = compute_topocentric_direction(params, sat, t) # u in CoMRS frame
Su = ft.lmn_to_xyz(attitude, Cu) # u in SRS frame
phi, zeta = compute_field_angles(Su, double_telescope=False)
pass
def observed_field_angles(source, attitude, sat, t, double_telescope=False):
"""
Ref. Paper eq. [12]-[13]
Return field angles according to Lindegren eq. 12
eta: along-scan field angle (== phi if double_telescope = False)
zeta: across-scan field angle
"""
Cu = source.unit_topocentric_function(sat, t) # u in CoMRS frame
Su = ft.lmn_to_xyz(attitude, Cu)
# if double_telescope is False, it will return (phi, zeta)
eta, zeta = compute_field_angles(Su, double_telescope)
return eta, zeta
def calculated_field_angles(calc_source,
attitude,
sat,
t,
double_telescope=False):
"""
Ref. Paper eq. [12]-[13]
Return field angles according to Lindegren eq. 12
eta: along-scan field angle
"""
alpha, delta, parallax, mu_alpha, mu_delta = calc_source.s_params[:]
params = np.array(
[alpha, delta, parallax, mu_alpha, mu_delta, calc_source.mu_radial])
Cu = compute_topocentric_direction(params, sat, t) # u in CoMRS frame
Su = ft.lmn_to_xyz(attitude, Cu) # u in SRS frame
eta, zeta = compute_field_angles(Su, double_telescope)
return eta, zeta
def observed_field_angles(source, attitude, sat, t, double_telescope=False):
"""
| Ref. Paper [LUDW2011]_ eq. [12]-[13]
| Return field angles according to Lindegren eq. 12. See :meth:`compute_field_angles`
:param source: [Source]
:param attitude: [quaternion] attitude at time t
:param sat: [Satellite]
:param t: [float] time at which we want the angles
:param double_telescope: [bool] If true, uses the model with two telescopes
:returns:
* eta: along-scan field angle (== phi if double_telescope = False)
* zeta: across-scan field angle
"""
Cu = source.unit_topocentric_function(sat, t) # u in CoMRS frame
Su = ft.lmn_to_xyz(attitude, Cu)
# if double_telescope is False, it will return (phi, zeta)
eta, zeta = compute_field_angles(Su, double_telescope)
return eta, zeta
def CoMRS_to_SRS_for_source_derivatives(self, CoMRS_derivatives, calc_source, t_L, source_index):
"""
| Ref. Paper [LUDW2011]_ eq. [72]
| rotate the frame from CoRMS (lmn) to SRS (xyz) for the given derivatives
:param CoMRS_derivatives: [list] of deriatives [du_dalpha, du_ddelta,
du_dparallax, du_dmualpha, du_dmudelta]
:param calc_source: [Calc_source]
:param t_L: [float] time of observation
:param source_index: [int]
"""
SRS_derivatives = []
if self.updating == 'source':
attitude = self.get_attitude_for_source(source_index, t_L)
elif self.updating == 'scanned source':
attitude = self.sat.func_attitude(t_L)
else: # attitude = self.get_attitude(t_L)
raise ValueError('Not yet implemented for this case')
for derivative in CoMRS_derivatives: # TODO: remove these ugly for loop
SRS_derivatives.append(ft.lmn_to_xyz(attitude, derivative))
return SRS_derivatives
def eta_angle(t, sat, source, FoV='centered'):
"""
Function to minimize in the scanner.
See `observed_field_angles()`
"""
Gamma_c = const.Gamma_c
Cu_unit = source.unit_topocentric_function(sat, t)
Su = ft.lmn_to_xyz(sat.func_attitude(t), Cu_unit)
Su_x, Su_y, Su_z = Su[:]
phi = np.arctan2(Su_y, Su_x)
field_index = np.sign(phi)
if FoV == 'centered':
eta = phi
elif FoV == 'preceding':
eta = phi + Gamma_c / 2
elif FoV == 'following':
eta = phi - Gamma_c / 2
else:
raise ValueError('incorrect FoV argument.')
return eta