def gcrs_posvel_from_itrf(loc, toas, obsname='obs'):
"""Return a list of PosVel instances for the observatory at the TOA times.
Observatory location should be given in the loc argument as an astropy
EarthLocation object. This location will be in the ITRF frame (i.e.
co-rotating with the Earth).
The optional obsname argument will be used as label in the returned
PosVel instance.
This routine returns a list of PosVel instances, containing the
positions (m) and velocities (m / s) at the times of the toas and
referenced to the Earth-centered Inertial (ECI, aka GCRS) coordinates.
This routine is basically SOFA's pvtob() [Position and velocity of
a terrestrial observing station] with an extra rotation from c2ixys()
[Form the celestial to intermediate-frame-of-date matrix given the CIP
X,Y and the CIO locator s].
"""
# If the input is a single TOA (i.e. a row from the table),
# then put it into a list
if type(toas) == table.row.Row:
ttoas = Time([toas['mjd']])
N = 1
elif type(toas) == table.table.Table:
N = len(toas)
ttoas = toas['mjd']
else:
if toas.isscalar:
ttoas = Time([toas])
else:
ttoas = toas
N = len(ttoas)
# Get various times from the TOAs as arrays
tts = np.asarray([(t.jd1, t.jd2) for t in ttoas.tt]).T
ut1s = np.asarray([(t.jd1, t.jd2) for t in ttoas.ut1]).T
mjds = np.asarray(ttoas.mjd)
# Get x, y coords of Celestial Intermediate Pole and CIO locator s
X, Y, S = erfa.xys00a(*tts)
# Get dX and dY from IERS A in arcsec and convert to radians
#dX = np.interp(mjds, iers_tab['MJD'], iers_tab['dX_2000A_B']) * asec2rad
#dY = np.interp(mjds, iers_tab['MJD'], iers_tab['dY_2000A_B']) * asec2rad
# Get dX and dY from IERS B in arcsec and convert to radians
dX = np.interp(mjds, iers_tab['MJD'], iers_tab['dX_2000A']) * asec2rad
dY = np.interp(mjds, iers_tab['MJD'], iers_tab['dY_2000A']) * asec2rad
# Get GCRS to CIRS matrices
rc2i = erfa.c2ixys(X + dX, Y + dY, S)
# Gets the TIO locator s'
sp = erfa.sp00(*tts)
# Get X and Y from IERS A in arcsec and convert to radians
#xp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_X_B']) * asec2rad
#yp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_Y_B']) * asec2rad
# Get X and Y from IERS B in arcsec and convert to radians
xp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_x']) * asec2rad
yp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_y']) * asec2rad
# Get the polar motion matrices
rpm = erfa.pom00(xp, yp, sp)
# Observatory geocentric coords in m
xyzm = np.array([a.to(u.m).value for a in loc.geocentric])
x, y, z = np.dot(xyzm, rpm).T
# Functions of Earth Rotation Angle
theta = erfa.era00(*ut1s)
s, c = np.sin(theta), np.cos(theta)
sx, cx = s * x, c * x
sy, cy = s * y, c * y
# Initial positions and velocities
iposs = np.asarray([cx - sy, sx + cy, z]).T
ivels = np.asarray([OM * (-sx - cy), OM * (cx - sy), \
np.zeros_like(x)]).T
# There is probably a way to do this with np.einsum or something...
# and here it is .
poss = np.empty((N, 3), dtype=np.float64)
vels = np.empty((N, 3), dtype=np.float64)
poss = np.einsum('ij,ijk->ik', iposs, rc2i)
vels = np.einsum('ij,ijk->ik', ivels, rc2i)
return utils.PosVel(poss.T * u.m,
vels.T * u.m / u.s,
obj=obsname,
origin="earth")
def topo_posvels(loc, toas, obsname='obs'):
"""Return a list of PosVel instances for the observatory at the TOA times.
Observatory location should be given in the loc argument as an astropy
EarthLocation object.
The optional obsname argument will be used as label in the returned
PosVel instance.
This routine returns a list of PosVel instances, containing the
positions (m) and velocities (m / s) at the times of the toas and
referenced to the ITRF geocentric coordinates. This routine is
basically SOFA's pvtob() with an extra rotation from c2ixys.
"""
# If the input is a single TOA (i.e. a row from the table),
# then put it into a list
if type(toas) == table.row.Row:
ttoas = Time([toas['mjd']])
N = 1
elif type(toas) == table.table.Table:
N = len(toas)
ttoas = toas['mjd']
else:
if toas.isscalar:
ttoas = Time([toas])
else:
ttoas = toas
N = len(ttoas)
# Get various times from the TOAs as arrays
tts = np.asarray([(t.jd1, t.jd2) for t in ttoas.tt]).T
ut1s = np.asarray([(t.jd1, t.jd2) for t in ttoas.ut1]).T
mjds = np.asarray(ttoas.mjd)
# Get x, y coords of Celestial Intermediate Pole and CIO locator s
X, Y, S = erfa.xys00a(*tts)
# Get dX and dY from IERS A in arcsec and convert to radians
#dX = np.interp(mjds, iers_tab['MJD'], iers_tab['dX_2000A_B']) * asec2rad
#dY = np.interp(mjds, iers_tab['MJD'], iers_tab['dY_2000A_B']) * asec2rad
# Get dX and dY from IERS B in arcsec and convert to radians
dX = np.interp(mjds, iers_tab['MJD'], iers_tab['dX_2000A']) * asec2rad
dY = np.interp(mjds, iers_tab['MJD'], iers_tab['dY_2000A']) * asec2rad
# Get GCRS to CIRS matrices
rc2i = erfa.c2ixys(X+dX, Y+dY, S)
# Gets the TIO locator s'
sp = erfa.sp00(*tts)
# Get X and Y from IERS A in arcsec and convert to radians
#xp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_X_B']) * asec2rad
#yp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_Y_B']) * asec2rad
# Get X and Y from IERS B in arcsec and convert to radians
xp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_x']) * asec2rad
yp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_y']) * asec2rad
# Get the polar motion matrices
rpm = erfa.pom00(xp, yp, sp)
# Observatory geocentric coords in m
xyzm = np.array([a.to(u.m).value for a in loc.geocentric])
x, y, z = np.dot(xyzm, rpm).T
# Functions of Earth Rotation Angle
theta = erfa.era00(*ut1s)
s, c = np.sin(theta), np.cos(theta)
sx, cx = s * x, c * x
sy, cy = s * y, c * y
# Initial positions and velocities
iposs = np.asarray([cx - sy, sx + cy, z]).T
ivels = np.asarray([OM * (-sx - cy), OM * (cx - sy), \
np.zeros_like(x)]).T
# There is probably a way to do this with np.einsum or something...
# and here it is .
poss = np.empty((N, 3), dtype=np.float64)
vels = np.empty((N, 3), dtype=np.float64)
poss = np.einsum('ij,ijk->ik', iposs, rc2i)
vels = np.einsum('ij,ijk->ik', ivels, rc2i)
return utils.PosVel(poss.T * u.m, vels.T * u.m / u.s, obj=obsname, origin="earth")
def topo_posvels(obsname, toas):
"""Return a list of PosVel instances for the observatory at the TOA times
This routine returns a list of PosVel instances, containing the
positions (m) and velocities (m / s) at the times of the toas and
referenced to the ITRF geocentric coordinates. This routine is
basically SOFA's pvtob() with an extra rotation from c2ixys.
"""
# If the input is a single TOA (i.e. a row from the table),
# then put it into a list
if type(toas) == table.row.Row:
ttoas = [toas['mjd']]
N = 1
else:
N = len(toas)
ttoas = toas['mjd']
# Get various times from the TOAs as arrays
tts = np.asarray([(toa.tt.jd1, toa.tt.jd2) for toa in ttoas]).T
ut1s = np.asarray([(toa.ut1.jd1, toa.ut1.jd2) for toa in ttoas]).T
mjds = np.asarray([toa.mjd for toa in ttoas])
# Get x, y coords of Celestial Intermediate Pole and CIO locator s
X, Y, S = erfa.xys00a(*tts)
# Get dX and dY from IERS A in arcsec and convert to radians
#dX = np.interp(mjds, iers_tab['MJD'], iers_tab['dX_2000A_B']) * asec2rad
#dY = np.interp(mjds, iers_tab['MJD'], iers_tab['dY_2000A_B']) * asec2rad
# Get dX and dY from IERS B in arcsec and convert to radians
dX = np.interp(mjds, iers_tab['MJD'], iers_tab['dX_2000A']) * asec2rad
dY = np.interp(mjds, iers_tab['MJD'], iers_tab['dY_2000A']) * asec2rad
# Get GCRS to CIRS matrices
rc2i = erfa.c2ixys(X + dX, Y + dY, S)
# Gets the TIO locator s'
sp = erfa.sp00(*tts)
# Get X and Y from IERS A in arcsec and convert to radians
#xp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_X_B']) * asec2rad
#yp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_Y_B']) * asec2rad
# Get X and Y from IERS B in arcsec and convert to radians
xp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_x']) * asec2rad
yp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_y']) * asec2rad
# Get the polar motion matrices
rpm = erfa.pom00(xp, yp, sp)
# Observatory geocentric coords in m
xyzm = np.array([a.to(u.m).value for a in \
observatories[obsname].loc.geocentric])
x, y, z = np.dot(xyzm, rpm).T
# Functions of Earth Rotation Angle
theta = erfa.era00(*ut1s)
s, c = np.sin(theta), np.cos(theta)
sx, cx = s * x, c * x
sy, cy = s * y, c * y
# Initial positions and velocities
iposs = np.asarray([cx - sy, sx + cy, z]).T
ivels = np.asarray([OM * (-sx - cy), OM * (cx - sy), \
np.zeros_like(x)]).T
# There is probably a way to do this with np.einsum or something...
poss = np.empty((N, 3), dtype=np.float64)
vels = np.empty((N, 3), dtype=np.float64)
for ii in range(N):
poss[ii] = np.dot(iposs[ii], rc2i[ii])
vels[ii] = np.dot(ivels[ii], rc2i[ii])
# Make a PosVel list for return
pvs = [utils.PosVel(p, v, obj=obsname, origin="EARTH") \
for p, v in zip(poss * u.m, vels * u.m / u.s)]
return pvs
def topo_posvels(obsname, toas):
"""Return a list of PosVel instances for the observatory at the TOA times
This routine returns a list of PosVel instances, containing the
positions (m) and velocities (m / s) at the times of the toas and
referenced to the ITRF geocentric coordinates. This routine is
basically SOFA's pvtob() with an extra rotation from c2ixys.
"""
# If the input is a single TOA (i.e. a row from the table),
# then put it into a list
if type(toas) == table.row.Row:
ttoas = [toas['mjd']]
N = 1
else:
N = len(toas)
ttoas = toas['mjd']
# Get various times from the TOAs as arrays
tts = np.asarray([(toa.tt.jd1, toa.tt.jd2) for toa in ttoas]).T
ut1s = np.asarray([(toa.ut1.jd1, toa.ut1.jd2) for toa in ttoas]).T
mjds = np.asarray([toa.mjd for toa in ttoas])
# Get x, y coords of Celestial Intermediate Pole and CIO locator s
X, Y, S = erfa.xys00a(*tts)
# Get dX and dY from IERS A in arcsec and convert to radians
#dX = np.interp(mjds, iers_tab['MJD'], iers_tab['dX_2000A_B']) * asec2rad
#dY = np.interp(mjds, iers_tab['MJD'], iers_tab['dY_2000A_B']) * asec2rad
# Get dX and dY from IERS B in arcsec and convert to radians
dX = np.interp(mjds, iers_tab['MJD'], iers_tab['dX_2000A']) * asec2rad
dY = np.interp(mjds, iers_tab['MJD'], iers_tab['dY_2000A']) * asec2rad
# Get GCRS to CIRS matrices
rc2i = erfa.c2ixys(X+dX, Y+dY, S)
# Gets the TIO locator s'
sp = erfa.sp00(*tts)
# Get X and Y from IERS A in arcsec and convert to radians
#xp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_X_B']) * asec2rad
#yp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_Y_B']) * asec2rad
# Get X and Y from IERS B in arcsec and convert to radians
xp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_x']) * asec2rad
yp = np.interp(mjds, iers_tab['MJD'], iers_tab['PM_y']) * asec2rad
# Get the polar motion matrices
rpm = erfa.pom00(xp, yp, sp)
# Observatory geocentric coords in m
xyzm = np.array([a.to(u.m).value for a in \
observatories[obsname].loc.geocentric])
x, y, z = np.dot(xyzm, rpm).T
# Functions of Earth Rotation Angle
theta = erfa.era00(*ut1s)
s, c = np.sin(theta), np.cos(theta)
sx, cx = s * x, c * x
sy, cy = s * y, c * y
# Initial positions and velocities
iposs = np.asarray([cx - sy, sx + cy, z]).T
ivels = np.asarray([OM * (-sx - cy), OM * (cx - sy), \
np.zeros_like(x)]).T
# There is probably a way to do this with np.einsum or something...
poss = np.empty((N, 3), dtype=np.float64)
vels = np.empty((N, 3), dtype=np.float64)
for ii in range(N):
poss[ii] = np.dot(iposs[ii], rc2i[ii])
vels[ii] = np.dot(ivels[ii], rc2i[ii])
# Make a PosVel list for return
pvs = [utils.PosVel(p, v, obj=obsname, origin="EARTH") \
for p, v in zip(poss * u.m, vels * u.m / u.s)]
return pvs