def get_antpos_ecef(antpos, lon):
"""
Compute the antenna positions in ECEF coordinates from rotECEF
Args:
antpos -- array of antenna positions. Should have shape (Nants, 3).
lon (float) -- telescope longitude, in radians
Returns:
ecef -- array of antenna positions in ECEF frame. Has shape (Nants, 3)
"""
import pyuvdata.utils as uvutils
ecef = uvutils.ECEF_from_rotECEF(antpos, lon)
return ecef
def test_antpos_units(casa_uvfits, tmp_path):
"""
Read uvfits, write miriad. Check written antpos are in ns.
"""
uv = casa_uvfits
testfile = str(tmp_path / "uv_antpos_units")
uv.write_miriad(testfile, clobber=True)
auv = aipy_extracts.UV(testfile)
aantpos = auv["antpos"].reshape(3, -1).T * const.c.to("m/ns").value
aantpos = aantpos[uv.antenna_numbers, :]
aantpos = (
uvutils.ECEF_from_rotECEF(aantpos, uv.telescope_location_lat_lon_alt[1])
- uv.telescope_location
)
assert np.allclose(aantpos, uv.antenna_positions)
def test_antpos_units():
"""
Read uvfits, write miriad. Check written antpos are in ns.
"""
uv = UVData()
uvfits_file = os.path.join(DATA_PATH,
'day2_TDEM0003_10s_norx_1src_1spw.uvfits')
testfile = os.path.join(DATA_PATH, 'test/uv_antpos_units')
uvtest.checkWarnings(uv.read_uvfits, [uvfits_file],
message='Telescope EVLA is not')
uv.write_miriad(testfile, clobber=True)
auv = amiriad.UV(testfile)
aantpos = auv['antpos'].reshape(3, -1).T * const.c.to('m/ns').value
aantpos = aantpos[uv.antenna_numbers, :]
aantpos = (uvutils.ECEF_from_rotECEF(
aantpos, uv.telescope_location_lat_lon_alt[1]) - uv.telescope_location)
nt.assert_true(np.allclose(aantpos, uv.antenna_positions))
def get_antpos_enu(antpos, lat, lon, alt):
"""
Compute the antenna positions in ENU coordinates from rotECEF.
Args:
antpos -- array of antenna positions. Should have shape (Nants, 3).
lat (float) -- telescope latitude, in radians
lon (float) -- telescope longitude, in radians
alt (float) -- telescope altitude, in meters
Returns:
enu -- array of antenna positions in ENU frame. Has shape (Nants, 3).
"""
import pyuvdata.utils as uvutils
ecef = uvutils.ECEF_from_rotECEF(antpos, lon)
enu = uvutils.ENU_from_ECEF(ecef, lat, lon, alt)
return enu
def test_mwa_ecef_conversion():
'''
Test based on comparing the antenna locations in a Cotter uvfits file to
the antenna locations in MWA_tools.
'''
test_data_file = os.path.join(DATA_PATH, 'mwa128_ant_layouts.npz')
f = np.load(test_data_file)
# From the STABXYZ table in a cotter-generated uvfits file, obsid = 1066666832
xyz = f['stabxyz']
# From the East/North/Height columns in a cotter-generated metafits file, obsid = 1066666832
enh = f['ENH']
# From a text file antenna_locations.txt in MWA_Tools/scripts
txt_topo = f['txt_topo']
# From the unphased uvw coordinates of obsid 1066666832, positions relative to antenna 0
# these aren't used in the current test, but are interesting and might help with phasing diagnosis in the future
uvw_topo = f['uvw_topo']
# Sky coordinates are flipped for uvw derived values
uvw_topo = -uvw_topo
uvw_topo += txt_topo[0]
# transpose these arrays to get them into the right shape
txt_topo = txt_topo.T
uvw_topo = uvw_topo.T
enh = enh.T
# ARRAYX, ARRAYY, ARRAYZ in ECEF frame from Cotter file
arrcent = f['arrcent']
lat, lon, alt = uvutils.LatLonAlt_from_XYZ(arrcent)
# The STABXYZ coordinates are defined with X through the local meridian,
# so rotate back to the prime meridian
new_xyz = uvutils.ECEF_from_rotECEF(xyz.T, lon)
# add in array center to get real ECEF
ecef_xyz = new_xyz + arrcent
enu = uvutils.ENU_from_ECEF(ecef_xyz.T, lat, lon, alt)
nt.assert_true(np.allclose(enu, enh))
# test other direction of ECEF rotation
rot_xyz = uvutils.rotECEF_from_ECEF(new_xyz, lon)
nt.assert_true(np.allclose(rot_xyz.T, xyz))
uvd.telescope_location_lat_lon_alt = (cofa_loc.lat * np.pi / 180.,
cofa_loc.lon * np.pi / 180.,
cofa_loc.elevation)
# loop over aa object
idx = 0
antpos = np.zeros((len(aa), 3))
ants_telescope = []
for iant, ant in enumerate(aa):
# test to see if antenna is "far" from center of the Earth
if np.linalg.norm(ant.pos) > 1e6:
# convert from ns -> m
pos = ant.pos * c_ns
# rotate from rotECEF -> ECEF
pos_ecef = uvutils.ECEF_from_rotECEF(pos, longitude)
# subtract off array location, to get just relative positions
rel_pos = pos_ecef - uvd.telescope_location
# save in array
antpos[idx, :] = rel_pos
# also save antenna number to list of antennas
ants_telescope.append(iant)
# increment counter
idx += 1
# set the antenna information
uvd.Nants_telescope = len(ants_telescope)
