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feat: add v2 pointing model for lat #1448

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Merged
skhrg merged 4 commits into from
Dec 2, 2025
Merged

feat: add v2 pointing model for lat #1448

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930455c
feat: add v2 pointing model for lat
skhrg Oct 27, 2025
1663971
fix: move new model into v1
skhrg Nov 25, 2025
9a62271
fix: remove v2 defaults and add v1 defaults
skhrg Dec 1, 2025
c7d56f2
feat: add a lat pointing model test
skhrg Dec 1, 2025
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45 changes: 41 additions & 4 deletions sotodlib/coords/pointing_model.py
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Original file line number Diff line number Diff line change
Expand Up @@ -125,11 +125,9 @@ def apply_pointing_model_lat(vers, params, ancil):

if vers == 'lat_naive':
return _new_boresight(ancil.samps, az=az, el=el, roll=roll)

if vers == "lat_v1":
elif vers == "lat_v1":
az1, el1, roll1 = model_lat_v1(params, az, el, roll)
return _new_boresight(ancil.samps, az=az1, el=el1, roll=roll1)

else:
raise ValueError(f'Unimplemented pointing model "{vers}"')

Expand All @@ -156,6 +154,10 @@ def model_lat_v1(params, az, el, roll):
- mir_center_{xi,eta}0: The (xi,eta) coordinate in the El-structure-centered
focal plane that appears fixed when the mirrors are rotated about the ray from
sky that hits the center of both mirrors.
- base_tilt_{cos,sin}: Base tilt coefficients, in radians.
- el_sag_{quad,lin}: Dimensionless coefficients for the quadradtic
and linear components of the elevation sag.
- el_sag_pivot: The elevation in radians to treat as the sag's zero point.

"""
_p = dict(param_defaults['lat_v1'])
Expand Down Expand Up @@ -217,7 +219,26 @@ def model_lat_v1(params, az, el, roll):
* q_el_roll * q_el_axis_center
* q_cr_roll * q_cr_center
)
new_az, el, roll = quat.decompose_lonlat(q_hs)* np.array([-1, 1, 1])[..., None]
az, el, roll = quat.decompose_lonlat(q_hs)* np.array([-1, 1, 1])[..., None]
cr = el - roll - np.deg2rad(60)

# Base tilt
q_base_tilt = get_base_tilt_q(params['base_tilt_cos'], params['base_tilt_sin'])

# El sag
el_sag = params['el_sag_quad']*(el - params['el_sag_pivot'])**2
el_sag += params['el_sag_lin']*(el - params['el_sag_pivot'])
el += el_sag

# Lonlat rotation after v1 model and el sag is applied
q_lonlat = quat.rotation_lonlat(-1 * az, el) * quat.euler(2, roll)

# Horizon Coordinates
q_hs = q_base_tilt * q_lonlat
new_az, el, _ = quat.decompose_lonlat(q_hs)* np.array([-1, 1, 1])[..., None]

# Get new roll with the modified el
roll = el - cr - np.deg2rad(60)

# Make corrected az as close as possible to the input az.
change = ((new_az - az_orig) + np.pi) % (2 * np.pi) - np.pi
Expand Down Expand Up @@ -311,6 +332,22 @@ def model_sat_v1(params, az, el, roll):
'mir_center_xi0': 0,
'mir_center_eta0': 0,
},
'lat_v2' : {
'enc_offset_az': 0,
'enc_offset_el': 0,
'enc_offset_cr': 0,
'el_axis_center_xi0': 0,
'el_axis_center_eta0': 0,
'cr_center_xi0': 0,
'cr_center_eta0': 0,
'mir_center_xi0': 0,
'mir_center_eta0': 0,
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@mhasself mhasself Nov 27, 2025

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Delete these -- this is still lat_v1.

As written, I believe the code will error if you pass it an old params dict. Because the updated defaults will not be loaded. A smoke test would be helpful here.

Please add LAT model test to tests/test_pointing_model.py, including backwards compatibility check.

'base_tilt_cos': 0,
'base_tilt_sin': 0,
'el_sag_quad': 0,
'el_sag_lin': 0,
'el_sag_pivot': np.pi/2.,
},
'sat_v1' : {
'enc_offset_az': 0.,
'enc_offset_el': 0.,
Expand Down