diff --git a/lisainstrument/instrument.py b/lisainstrument/instrument.py
index 8328c71895812d5dbba08300db6cef0cbeb3ba17..fa420b48b3664c19b48adb6b4885a7b00360899f 100755
--- a/lisainstrument/instrument.py
+++ b/lisainstrument/instrument.py
@@ -87,8 +87,8 @@ class Instrument:
# Optical pathlength noises
backlink_asds=3E-12, backlink_fknees=2E-3, testmass_asds=2.4E-15, testmass_fknees=0.4E-3,
oms_asds=(6.35E-12, 1.25E-11, 1.42E-12, 3.38E-12, 3.32E-12, 7.90E-12), oms_fknees=2E-3,
- # TCB synchronization
- sync_asds=0.42,
+ # MOC time correlation
+ moc_time_correlation_asds=0.42,
# Tilt-to-length (TTL)
ttl_coeffs='default',
sc_jitter_asds=(5E-9, 5E-9, 5E-9), sc_jitter_fknees=(8E-4, 8E-4, 8E-4),
@@ -147,16 +147,17 @@ class Instrument:
clock_freqoffsets: dictionary of clock frequency offsets [s^-1], or 'default'
clock_freqlindrifts: dictionary of clock frequency linear drifts [s^-2], or 'default'
clock_freqquaddrifts: dictionary of clock frequency quadratic drifts [s^-2], or 'default'
- clockinv_tolerance: convergence tolerance for timer deviation inversion [s]
- clockinv_maxiter: maximum number of iterations for timer deviation inversion
+ clockinv_tolerance: convergence tolerance for clock noise inversion [s]
+ clockinv_maxiter: maximum number of iterations for clock noise inversion
backlink_asds: dictionary of amplitude spectral densities for backlink noise [m/sqrt(Hz)]
backlink_fknees: dictionary of cutoff frequencied for backlink noise [Hz]
testmass_asds: dictionary of amplitude spectral densities for test-mass noise [ms^(-2)/sqrt(Hz)]
testmass_fknees: dictionary of cutoff frequencies for test-mass noise [Hz]
oms_asds: tuple of dictionaries of amplitude spectral densities for OMS noise [m/sqrt(Hz)],
ordered as (isi_carrier, isi_usb, tmi_carrier, tmi_usb, rfi_carrier, rfi_usb)
- sync_asds: dictionary of amplitude spectral densities for TCB synchronization noise [s/sqrt(Hz)],
- the default ASD seems rather high, this is due to the small sampling rate (default 1 / 86400s)
+ moc_time_correlation_asds: dictionary of amplitude spectral densities for MOC time
+ correlation noise [s/sqrt(Hz)], the default ASD seems rather high, this is due
+ to the small sampling rate (default 1 / 86400s)
oms_fknees: dictionary of cutoff frequencies for OMS noise
ttl_coeffs: tuple (local_phi, distant_phi, local_eta, distant_eta) of dictionaries of
tilt-to-length coefficients on each MOSA [m/rad], 'default' for a default set of
@@ -318,8 +319,8 @@ class Instrument:
else:
self.clock_freqquaddrifts = ForEachSC(clock_freqquaddrifts)
- # TCB synchronization
- self.sync_asds = ForEachSC(sync_asds)
+ # MOC time correlation
+ self.moc_time_correlation_asds = ForEachSC(moc_time_correlation_asds)
# Clock-noise inversion
self.clockinv_tolerance = float(clockinv_tolerance)
@@ -588,7 +589,7 @@ class Instrument:
'13': 8.33159404, '32': 8.30446786, '21': 8.33159402,
})
self.d_pprs = ForEachMOSA(0)
- self.tps_proper_time_deviations = ForEachSC(0)
+ self.tps_wrt_tcb = ForEachSC(0)
self.orbit_dataset = None
elif isinstance(orbits, str):
logger.info("Using orbit file '%s'", orbits)
@@ -615,7 +616,7 @@ class Instrument:
self.d_pprs = self.pprs.transformed(lambda _, x:
0 if np.isscalar(x) else np.gradient(x, self.physics_dt)
)
- self.tps_proper_time_deviations = ForEachSC(0)
+ self.tps_wrt_tcb = ForEachSC(0)
self.orbit_dataset = None
def init_orbits_file_1_0(self, orbitf):
@@ -643,7 +644,7 @@ class Instrument:
raise ValueError(f"invalid orbit dataset '{self.orbit_dataset}'")
return InterpolatedUnivariateSpline(times, values, k=5, ext='raise')
- def tps_proper_time_deviations(sc):
+ def tps_wrt_tcb(sc):
if self.orbit_dataset == 'tcb/ltt':
return lambda x: 0
if self.orbit_dataset == 'tps/ppr':
@@ -664,8 +665,8 @@ class Instrument:
self.pprs = ForEachMOSA(lambda mosa: pprs(mosa)(self.physics_t))
logger.debug("Interpolating proper pseudo-range derivatives")
self.d_pprs = ForEachMOSA(lambda mosa: d_pprs(mosa)(self.physics_t))
- logger.debug("Interpolating proper time deviation from TCB")
- self.tps_proper_time_deviations = ForEachSC(lambda sc: tps_proper_time_deviations(sc)(self.telemetry_t))
+ logger.debug("Interpolating TPSs with respect to TCB")
+ self.tps_wrt_tcb = ForEachSC(lambda sc: tps_wrt_tcb(sc)(self.physics_t_withinitial))
except ValueError as error:
logger.error("Missing orbit information at \n%s", self.physics_t)
raise ValueError("missing orbit information, use longer orbit file or adjust sampling") from error
@@ -690,12 +691,12 @@ class Instrument:
logger.debug("Interpolating proper pseudo-range derivatives")
dataset = orbitf['tcb/d_ltt'] if self.orbit_dataset == 'tcb/ltt' else orbitf['tps/d_ppr']
self.d_pprs = ForEachMOSA(lambda mosa: interpolate(dataset[:, link_index[mosa]], self.physics_t))
- logger.debug("Interpolating proper time deviation from TCB")
+ logger.debug("Interpolating TPSs with respect to TCB")
if self.orbit_dataset == 'tcb/ltt':
- self.tps_proper_time_deviations = ForEachSC(lambda sc: 0)
+ self.tps_wrt_tcb = ForEachSC(lambda sc: 0)
else:
dataset = orbitf['tcb/delta_tau']
- self.tps_proper_time_deviations = ForEachSC(lambda sc: interpolate(dataset[:, sc_index[sc]], self.physics_t))
+ self.tps_wrt_tcb = ForEachSC(lambda sc: interpolate(dataset[:, sc_index[sc]], self.physics_t))
except ValueError as error:
logger.error("Missing orbit information at \n%s", self.physics_t)
raise ValueError("missing orbit information, use longer orbit file or adjust sampling") from error
@@ -850,10 +851,7 @@ class Instrument:
self.sync_asds = ForEachSC(0)
def disable_clock_noises(self):
- """Turn off all imperfections on clocks.
-
- This includes offsets, and frequency offsets and deviations.
- """
+ """Turn off all imperfections on clocks."""
self.clock_asds = ForEachSC(0)
self.clock_offsets = ForEachSC(0)
self.clock_freqoffsets = ForEachSC(0)
@@ -902,37 +900,41 @@ class Instrument:
self.simulate_noises()
- logger.debug("Computing local timer deviations")
- t = self.physics_et_withinitial
- self.local_timer_deviations_withinitial = \
+ ## MOC time correlations
+
+ logger.debug("Computing local THE with respect to TPS")
+ t = self.physics_et
+ self.the_wrt_tps_local = \
self.clock_offsets \
+ self.clock_freqoffsets * t \
+ self.clock_freqlindrifts * t**2 / 2 \
+ self.clock_freqquaddrifts * t**3 / 3 \
- + ForEachSC(lambda sc:
- cumulative_trapezoid(np.broadcast_to(
- self.clock_noise_fluctuations_withinitial[sc],
- self.physics_size + self.initial_telemetry_physics_size),
- dx=self.physics_dt, initial=0)
- )
-
- self.local_timer_deviations = self.local_timer_deviations_withinitial.transformed(
- lambda _, x: x if np.isscalar(x) else x[self.initial_telemetry_physics_size:]
- )
-
- ## Timer deviations from TCB
+ + self.integrated_clock_noise_fluctuations
+ logger.debug("Computing THE with respect to TCB")
+ t = self.physics_et_withinitial
+ self.the_wrt_tcb_withinitial = \
+ self.tps_wrt_tcb \
+ + self.clock_offsets \
+ + self.clock_freqoffsets * (t + self.tps_wrt_tcb) \
+ + self.clock_freqlindrifts * (t + self.tps_wrt_tcb)**2 / 2 \
+ + self.clock_freqquaddrifts * (t + self.tps_wrt_tcb)**3 / 3 \
+ + self.tps_wrt_tcb * self.clock_noise_fluctuations_withinitial \
+ + self.integrated_clock_noise_fluctuations_withinitial
+
+ logger.debug("Computing MOC time correlations")
physics_to_telemetry = lambda _, x: x[::self.physics_upsampling * self.telemetry_downsampling]
- self.tcb_timer_deviations = self.tcb_sync_noises \
- + self.local_timer_deviations_withinitial.transformed(physics_to_telemetry)
+ self.moc_time_correlations = self.moc_time_correlation_noises \
+ + self.the_wrt_tcb_withinitial.transformed(physics_to_telemetry)
## TDIR tone
+ logger.debug("Forming TDIR assistance tones")
self.tdir_tones = ForEachMOSA(lambda mosa:
0 if self.tdir_tone_amplitudes[mosa] == 0 \
else self.tdir_tone_amplitudes[mosa] * np.sin(
2 * np.pi * self.tdir_tone_frequencies[mosa]
- * (self.physics_et + self.local_timer_deviations[mosa[0]])
+ * (self.physics_et + self.the_wrt_tps_local[mosa[0]])
+ self.tdir_tone_initial_phases[mosa]
)
)
@@ -993,9 +995,9 @@ class Instrument:
- (self.central_freq + self.local_usb_offsets) * self.gws \
- (self.central_freq + self.local_usb_offsets) * self.local_ttls / c
- logger.debug("Propagating timer deviations to distant MOSAs")
- self.distant_timer_deviations = \
- self.local_timer_deviations.for_each_mosa().distant() \
+ logger.debug("Propagating local THEs with respect to TPS to distant MOSAs")
+ self.the_wrt_tps_distant = \
+ self.the_wrt_tps_local.for_each_mosa().distant() \
.transformed(lambda mosa, x: self.interpolate(x, -self.pprs[mosa])
- self.pprs[mosa]
)
@@ -1083,9 +1085,9 @@ class Instrument:
## Measured pseudo-ranging on TPS grid (high-frequency)
logger.info("Computing measured pseudo-ranges on TPS")
- self.tps_mprs = \
- self.local_timer_deviations \
- - self.distant_timer_deviations + self.ranging_noises
+ self.tps_mprs = self.the_wrt_tps_local - self.the_wrt_tps_distant \
+ + self.ranging_noises
+
## Test-mass interferometer local beams
@@ -1203,12 +1205,12 @@ class Instrument:
## Sampling beatnotes, DWS measurements, and measured pseudo-ranges to THE grid
- logger.info("Inverting timer deviations")
- self.inverse_timer_deviations = self.local_timer_deviations \
- .transformed(lambda sc, x: self.invert_timer_deviations(x, sc))
+ logger.info("Inverting THE with respect to TPS")
+ self.tps_wrt_the = self.the_wrt_tps_local \
+ .transformed(lambda sc, x: self.invert_the_wrt_tps(x, sc))
self.timestamped = \
- lambda mosa, x: self.interpolate(x, -self.inverse_timer_deviations.for_each_mosa()[mosa])
+ lambda mosa, x: self.interpolate(x, -self.tps_wrt_the.for_each_mosa()[mosa])
logger.info("Sampling inter-spacecraft beatnotes to THE grid")
@@ -1413,7 +1415,7 @@ class Instrument:
## Closing simulation
logger.info("Simulation complete")
- def simulate_noises(self):
+ def simulate_noises(self): # pylint: disable=too-many-statements
"""Generate noise time series."""
## Laser noise
@@ -1453,6 +1455,23 @@ class Instrument:
lambda _, x: x if np.isscalar(x) else x[self.initial_telemetry_physics_size:]
)
+ logger.debug("Integrating clock noise fluctuations")
+
+ # Include initial telemetry time period
+ self.integrated_clock_noise_fluctuations_withinitial = \
+ ForEachSC(lambda sc:
+ cumulative_trapezoid(np.broadcast_to(
+ self.clock_noise_fluctuations_withinitial[sc],
+ self.physics_size + self.initial_telemetry_physics_size),
+ dx=self.physics_dt, initial=0)
+ )
+
+ # Slice to only select physics period
+ self.integrated_clock_noise_fluctuations = \
+ self.integrated_clock_noise_fluctuations_withinitial.transformed(
+ lambda _, x: x if np.isscalar(x) else x[self.initial_telemetry_physics_size:]
+ )
+
## Modulation noise
logger.info("Generating modulation noise")
@@ -1529,10 +1548,13 @@ class Instrument:
noises.dws(self.physics_fs, self.physics_size, self.dws_asds[mosa])
)
- ## TCB synchronization noise
+ ## MOC time correlation noise
- self.tcb_sync_noises = ForEachSC(lambda sc:
- noises.tcb_sync(self.telemetry_fs, self.telemetry_size, self.sync_asds[sc])
+ self.moc_time_correlation_noises = ForEachSC(lambda sc:
+ noises.moc_time_correlation(
+ self.telemetry_fs,
+ self.telemetry_size,
+ self.moc_time_correlation_asds[sc])
)
## Angular jitters
@@ -1719,37 +1741,37 @@ class Instrument:
if not just_locked:
raise RuntimeError(f"cannot apply locking conditions to remaining lasers '{list(dependencies.keys())}'")
- def invert_timer_deviations(self, timer_deviations, sc):
- """Invert timer deviations of a given spacecraft.
+ def invert_the_wrt_tps(self, the_wrt_tps, sc):
+ """Invert THE with respect to TPS of a given spacecraft.
We recursively solve the implicit equation dtau(tau) = dtau_hat(tau - dtau(tau)) until the
convergence criteria (tolerance) is met, or we exceed the maximum number of iterations.
Args:
- timer_deviations: array of timer deviations
+ the_wrt_tps: array of THEs with respect to TPS
sc: spacecraft index
"""
- logger.debug("Inverting timer deviations for spacecraft %s", sc)
+ logger.debug("Inverting THE with respect to TPS for spacecraft %s", sc)
logger.debug("Solving iteratively (tolerance=%s s, maxiter=%s)",
self.clockinv_tolerance, self.clockinv_maxiter)
# Drop samples at the edges to compute error
- edge = min(100, len(timer_deviations) // 2 - 1)
+ edge = min(100, len(the_wrt_tps) // 2 - 1)
error = 0
niter = 0
- next_inverse = timer_deviations
+ next_inverse = the_wrt_tps
while not niter or error > self.clockinv_tolerance:
if niter >= self.clockinv_maxiter:
logger.warning("Maximum number of iterations '%s' reached for SC %s (error=%.2E)", niter, sc, error)
break
logger.debug("Starting iteration #%s", niter)
inverse = next_inverse
- next_inverse = self.interpolate(timer_deviations, -inverse)
+ next_inverse = self.interpolate(the_wrt_tps, -inverse)
error = np.max(np.abs((inverse - next_inverse)[edge:-edge]))
logger.debug("End of iteration %s, with an error of %.2E s", niter, error)
niter += 1
- logger.debug("End of timer deviation inversion after %s iterations with an error of %.2E s", niter, error)
+ logger.debug("End of THE with respect to TCB inversion after %s iterations with an error of %.2E s", niter, error)
return inverse
def _write_attr(self, hdf5, *names):
@@ -1847,6 +1869,9 @@ class Instrument:
self.pprs.write(hdf5, 'pprs')
self.d_pprs.write(hdf5, 'd_pprs')
+ logger.debug("Writing TPS with respect to TCB to '%s'", output)
+ self.tps_wrt_tcb.write(hdf5, 'tps_wrt_tcb')
+
logger.debug("Writing gravitational-wave responses to '%s'", output)
self.gws.write(hdf5, 'gws')
@@ -1863,7 +1888,12 @@ class Instrument:
logger.debug("Writing clock noise to '%s'", output)
self.clock_noise_offsets.write(hdf5, 'clock_noise_offsets')
self.clock_noise_fluctuations.write(hdf5, 'clock_noise_fluctuations')
- self.clock_noise_fluctuations_withinitial.write(hdf5, 'clock_noise_fluctuations_withinitial')
+ self.clock_noise_fluctuations_withinitial.write(
+ hdf5, 'clock_noise_fluctuations_withinitial')
+ self.integrated_clock_noise_fluctuations_withinitial.write(
+ hdf5, 'integrated_clock_noise_fluctuations_withinitial')
+ self.integrated_clock_noise_fluctuations.write(
+ hdf5, 'integrated_clock_noise_fluctuations')
logger.debug("Writing modulation noise to '%s'", output)
self.modulation_noises.write(hdf5, 'modulation_noises')
@@ -1885,8 +1915,8 @@ class Instrument:
self.oms_rfi_carrier_noises.write(hdf5, 'oms_rfi_carrier_noises')
self.oms_rfi_usb_noises.write(hdf5, 'oms_rfi_usb_noises')
- logger.debug("Writing TCB synchronization noise to '%s'", output)
- self.tcb_sync_noises.write(hdf5, 'tcb_sync_noises')
+ logger.debug("Writing MOC time correlation noise to '%s'", output)
+ self.moc_time_correlation_noises.write(hdf5, 'moc_time_correlation_noises')
logger.debug("Writing spacecraft angular jitter to '%s'", output)
self.sc_jitter_phis.write(hdf5, 'sc_jitter_phis')
@@ -1906,9 +1936,14 @@ class Instrument:
self.local_usb_offsets.write(hdf5, 'local_usb_offsets')
self.local_usb_fluctuations.write(hdf5, 'local_usb_fluctuations')
- logger.debug("Writing local timer deviations to '%s'", output)
- self.local_timer_deviations.write(hdf5, 'local_timer_deviations')
- self.local_timer_deviations_withinitial.write(hdf5, 'local_timer_deviations_withinitial')
+ logger.debug("Writing local THE with respect to TPS to '%s'", output)
+ self.the_wrt_tps_local.write(hdf5, 'the_wrt_tps_local')
+
+ logger.debug("Writing THE with respect to TCB to '%s'", output)
+ self.the_wrt_tcb_withinitial.write(hdf5, 'the_wrt_tcb_withinitial')
+
+ logger.debug("Writing MOC time correlations to '%s'", output)
+ self.moc_time_correlations.write(hdf5, 'moc_time_correlations')
logger.debug("Writing tilt-to-length couplings to '%s'", output)
self.local_ttls.write(hdf5, 'local_ttls')
@@ -1920,8 +1955,8 @@ class Instrument:
self.distant_usb_offsets.write(hdf5, 'distant_usb_offsets')
self.distant_usb_fluctuations.write(hdf5, 'distant_usb_fluctuations')
- logger.debug("Writing propagated timer deviations to '%s'", output)
- self.distant_timer_deviations.write(hdf5, 'distant_timer_deviations')
+ logger.debug("Writing propagated THEs with respect to TCB to '%s'", output)
+ self.the_wrt_tps_distant.write(hdf5, 'the_wrt_tcb_distant')
logger.debug("Writing propagated adjacent beams to '%s'", output)
self.adjacent_carrier_offsets.write(hdf5, 'adjacent_carrier_offsets')
@@ -1990,8 +2025,8 @@ class Instrument:
self.tps_rfi_usb_offsets.write(hdf5, 'tps_rfi_usb_offsets')
self.tps_rfi_usb_fluctuations.write(hdf5, 'tps_rfi_usb_fluctuations')
- logger.debug("Writing inverted timer deviations to '%s'", output)
- self.inverse_timer_deviations.write(hdf5, 'inverse_timer_deviations')
+ logger.debug("Writing TPS with respect to THE to '%s'", output)
+ self.tps_wrt_the.write(hdf5, 'tps_wrt_the')
logger.debug("Writing inter-spacecraft beatnotes sampled to THE grid to '%s'", output)
self.the_isi_carrier_offsets.write(hdf5, 'the_isi_carrier_offsets')
@@ -2095,9 +2130,6 @@ class Instrument:
self.rfi_carriers.write(hdf5, 'rfi_carriers')
self.rfi_usbs.write(hdf5, 'rfi_usbs')
- logger.debug("Write timer deviations from TCB to '%s'", output)
- self.tcb_timer_deviations.write(hdf5, 'tcb_timer_deviations')
-
logger.info("Closing measurement file '%s'", output)
def plot_fluctuations(self, output=None, skip=0):
diff --git a/lisainstrument/noises.py b/lisainstrument/noises.py
index 57b854b0028152abff22b216c3f79f8ea2043f0b..a49ff2ee7d7b55e730c690930693a1997ab558c7 100644
--- a/lisainstrument/noises.py
+++ b/lisainstrument/noises.py
@@ -321,19 +321,20 @@ def dws(fs, size, asd):
logger.debug("Generating DWS measurement (fs=%s Hz, size=%s, asd=%s rad/sqrt(Hz))", fs, size, asd)
return violet(fs, size, 2 * pi * asd)
-def tcb_sync(fs, size, asd):
- """TCB synchronization noise.
+def moc_time_correlation(fs, size, asd):
+ """MOC time correlation noise.
- High-level noise model for the uncertainty we have in estimating
- the TCB timer deviations, i.e., the equivalent TCB times for the
+ High-level noise model for the uncertainty we have in computing the MOC
+ time correlation (or time couples), i.e., the equivalent TCB times for the
equally-sampled TPS timestamps.
Assumed to be a white noise in timing,
- S_tcbsnc(f) [s] = asd^2.
+ S_moc(f) [s] = asd^2.
Args:
asd: amplitude spectral density [s/sqrt(Hz)]
"""
- logger.debug("Generating TCB synchronization noise (fs=%s Hz, size=%s, asd=%s s/sqrt(Hz))", fs, size, asd)
+ logger.debug("Generating MOC time correlation noise (fs=%s Hz, size=%s, "
+ "asd=%s s/sqrt(Hz))", fs, size, asd)
return white(fs, size, asd)