rss_ringoccs.calibration.power_normalization module¶

Purpose:	Normalize frequency-corrected power using a polynomial fit of specified order.
Dependencies:	numpy scipy matplotlib

class rss_ringoccs.calibration.power_normalization.Normalization(spm_raw, IQ_c, geo_inst, order=3, fittype='poly', interact=False, verbose=False, write_file=False)¶

Bases: object

Purpose:	Finds freespace power based on ring geometry, locations of gaps computed by the Geometry class, and signal power relative to median power within the gaps. Fits the freespace power with a polynomial. If desired, this fitting process can be interactive. A plot will be saved following rss_ringoccs nomenclature to visualize the fit results.

Arguments

spm_raw (np.ndarray):
	SPM as sampled in the raw data
IQ_c (np.ndarray):
	frequency-corrected signal corresponding to spm_raw
geo_inst (np.ndarray):
	instance of the Geometry class, used to estimate the freespace regions within and surrounding the ring system, accounting for Saturn occultation and the Keplerian geometry of the rings
rho_km_vals (np.ndarray):
	radial intercept poin of occultation in km

Keyword Arguments

interact (bool):
verbose (bool):	when True, outputs information to command line about the freespace power fitting progress and results. All results will be output to the CAL.LBL file regardless of this keyword. Default is False.
order (float):	a whole number specifying the order of the polynomial fit to the freespace power. Default is 3.
	If True, allows user to interactively adjust fit to the freespace power. Default is False.
fittype (str):	Type of fit to freespace regions. Default is a polynomial fit.

create_mask(spm, gaps_spm, pc)¶

Purpose:

Set mask and gaps attribute.

Arguments:

spm (np.ndarray):
	SPM in seconds of the downsampled signal
rho (np.ndarray):
	occultation intercept radius of the downsampled signal
gaps_spm (list):
	location of freespace regions as predicted by the gap-finding routines `get_freespace.py` using tabulated orbital parameters.
pc (np.ndarray):
	phase-corrected downsampled power where $P_c=\|I_c^2+iQ_c^2\|$ . Sets attributes
mask (np.ndarray):
	array of booleans wherein True designates data corresponding to freespace power and False data corresponding to occultation events
gaps (list):	an Nx2 list of lower and upper radial limits in km for each of N gaps designated

downsample_IQ(spm_raw, IQ_c_raw, dt_down=0.5, verbose=False)¶

Purpose:

Downsample complex signal to specified time spacing to avoid diffraction pattern affecting freespace power fit

Arguments:

spm_raw (np.ndarray):
	raw SPM values
IQ_c_raw (np.nparray):
	$I_c+iQ_c$ sampled at the raw SPM rate

Keyword Arguments:

dt_down (float):
	Time spacing to downsample to
verbose (bool):	If True, prints downsampled results

Returns:

spm_vals_down (np.ndarray):
	SPM values after downsampling
rho_km_vals_down (np.ndarray):
	Rho values after downsampling
p_obs_down (np.ndarray):
	Observed power after downsampling

extract_list_from_str(gaps_str)¶

Purpose:

Extract an Nx2 list from the string of user input freespace regions.

Arguments:

gaps_str (str):	string containing the user input freespace regions.

Returns:

gaps (list):	an Nx2 list of floats indicating the lower and upper limits to the user-specific freespace regions.

fit_check(spm_down, p_obs_down, freespace_spm, order)¶

Purpose:

Allows user to update the freespace regions and fit order during the freespace power fitting step. This is done by prompting the user for input in the command line and displaying the results of their input for the polynomial fit to the freespace power. Only called if the Normalization keyword interact is set to True.

Arguments:

gaps_str (str):	string containing the user input freespace regions.

Returns:

gaps (list):	an Nx2 list of floats indicating the lower and upper limits to the user-specific freespace regions.

fit_freespace_power(spm, power, order=3, fittype='poly')¶

Arguments:

spm (np.ndarray):
	downsampled SPM
power (np.ndarray):
	absolute square of downsampled phase-corrected signal

Keyword Arguments:

order (float):

order of the fit, whole number between 1 and 5. Default order is 3.

type (str):

type of fit to use, default is ‘poly’. Options are

‘poly’ a single polynomial
‘spline’ an unsmoothed spline fit

Returns

fit (np.ndarray):
	best fit to freespace power

hfit_med(p_obs_down)¶

plot_power_profile(spm, pow, gaps, order, save=False)¶

Purpose:

Plot results of the freespace power for total profile and each individual freespace region and either show plot in a GUI or save it to a file. File name will match the *.LBL and *.TAB nomenclature.

Arguments:

spm (np.ndarray):
	SPM sampled by `calc_freq_offset` when calculating the offset frequencies for the occultation
pow (np.ndarray):
	residual sky frequency
gaps (np.ndarray):
	gap edges used to select freespace power
order (float):	order of polynomial fit to the residual sky frequency

Keyword Arguments:

save (bool):	If True, saves plots to file. Otherwise, plot is shown in GUI. Default is False.