API Reference

class ECHO.observations.Observation(lat, lon, frequency=None, description=None)

The class object for making observations.

Parameters

  • lat (float) – , latitude of receiving antenna (degrees)

  • lon (float), longitude of receiving antenna (degrees) –

  • frequency (int) – the reference frequency of the transmitter (MHz)

  • channel (int) –

  • description (str) – , text string with information about observation

class Sortie(sortie_tlog, sortie_ulog, sortie_data, sortie_num, ref_f, sortie_name=None, sortie_title=None)

A sortie is created by three files: a ulog, a tlog, and an LWA data file. The data from these files is read and compiled into arrays.

apply_bootstart()

Puts drone data on absolute GPS-based time scale.

Uses GPS messages in on-board ulog to calibrate times of positions logged on ground station.

flag_endpoints()

Flag data arrays based on mission start/end.

Reads in “global_t” and “waypoint_t” from the tlog data dictionary.

“global_t” contains continuous position data from drone telemetry during the entire sortie. “waypoint_t” contains the position data for each navigational waypoint used to maneuver the drone.

Updates flagged_data and mission_data properties for a sortie

flag_waypoints()

Flag data arrays based on waypoint data.

Args:

flag_yaws()
get_bootstart()

Uses the GPS time to calculate the time at drone boot.

get_freq_chans()

Find the channel for our reference frequency.

Args:

Returns:

plot()

Creates multiple plots showing position data for sortie.

Tlog X/Y Position, ULog X/Y Position, X Position / Time, Y Position / Time, Z Position / Time:

Returns

ULog X/Y Position: X Position / Time: Y Position / Time: Z Position / Time:

Return type

Tlog X/Y Position

plot_flags()

Creates a plot showing flagged positions for sortie.

Return:

read()

Read in the sortie from associated data files.

The stored tlog, ulog, and receiver datafiles are opened and copied into dictionaries.

Returns

A dictionary containing info from the sortie tlog u_dict (dict): A dictionary containing info from the sortie ulog data_dict (dict): A dictionary containing info from the sortie receiver datafile

Return type

t_dict (dict)

addSortie(tlog, ulog, data, sortie_name=None, sortie_title=None)

Add a sortie to the current observation class.

Parameters

  • tlog (file) – txt file for the tlog data

  • ulog (file) – txt file for the ulog data

  • data (file) – txt file for the receiver data

  • sortie_name (str) – unique name for this sortie

  • sortie_title (str) – display title for this sortie

combine_sorties()

Combine our current list of sorties to create a data object for position.

Sorts currently added sorties by timestamp, then aggregates into a single array

Returns

‘Epoch Time(s), Lat(deg), Lon(deg), Alt(m from ground), Yaw(deg)’ for every sortie

Return type

dataproduct (array)

flagSorties()

Flag the sortie for start and endpoints, as well as waypoints.

interpolate_rx(obsNum, tuning, polarization)

Takes position-times of the drone and interpolate the receiver data to the same dimensions as position data.

Parameters

  • obsNum (int) – the number of the observation to use

  • tuning (int) – the number of the tuning to use, 1 or 2

  • pol (str) – which polarization to use (‘XX’, ‘YY’, ‘YX’, ‘XY’)

Returns

‘Epoch Time(s), Lat(deg), Lon(deg), Alt(m from ground), Yaw(deg), Radio Spectra’

Return type

refined_array (array)

make_beam(lat=None, lon=None)

Read in the refined array and create a beam.

Parameters

  • () (lon) – latitude of the receiver instrument

  • () – longitude of the receiver instrument

Returns:

plot_beam(fits=False, beamfile=None, countsfile=None)

Plot the healpix beam from our observation object.

Optionally plot beams read in from beam files.

Parameters

  • fits (bool) –

  • beamfile (str) –

  • countsfile (str) –

Returns:

plot_grid(*args, **kwargs)

Plot a grid view of the beam.

Parameters

  • *args – Variable length argument list.

  • **kwargs – Arbitrary keyword arguments.

plot_isometric(figsize=5, 5, *args, **kwargs)

Plot polar diagrams of the received beam.

Parameters

  • figsize (tuple) – figure size for plot

  • *args – Variable length argument list.

  • **kwargs – Arbitrary keyword arguments.

plot_mollview(*args, **kwargs)

Plot a mollview of the beam using

Parameters

  • *args – Variable length argument list.

  • **kwargs – Arbitrary keyword arguments.

plot_polar(altitude, *args, **kwargs)

Plot polar diagrams of the received beam.

Parameters

  • altitude – angle from zenith in degrees

  • *args – Variable length argument list.

  • **kwargs – Arbitrary keyword arguments.

plot_slices(figsize=None, *args, **kwargs)

Plot E and H plane slices of the beam

Parameters

  • figsize (tuple) – figure size for plot

  • *args – Variable length argument list.

  • **kwargs – Arbitrary keyword arguments.

Returns:

read_sorties()

Reads in the data files for a given sortie.

sort_sorties()

Sort our current list of sorties by time, using the first entry in each.

At any point we may need to sort the list of sorties by time. It’s preferable to do this rather than sort the data arrays after combining.

Returns

Sortie object

Return type

s

write_beam(prefix)

Write the beam file out to .fits.

Parameters

prefix (str) – A string used to name and identify the output files.

Returns:

class ECHO.beams.Beam(beam_type, beamfile=None)

The Beam class is the container object for various ECHO beams.

A beam can be made using data from the observation object. This will likely use pyuvbeam for stuff.

beamlist

List of beams created with this class.

Type

list

efield

numpy array for efield data.

Type

array, optional

power

numpy array for efield data.

Type

array, optional

make_hpx_beam(data_array, lat=None, lon=None)

Read in the refined array and create a beam.

Parameters

  • () (lon) – latitude of the receiver instrument

  • () – longitude of the receiver instrument

Returns:

read_cst_beam(CST_txtfile, beam_type, frequency, telescope_name, feed_name, feed_version, model_name, model_version, feed_pol)

Reads in a ASCII formatted CST export file and returns a beam model using pyuvbeam.

Parameters

  • CST_txtfile – CST export file

  • beam_type (str) – ‘efield’ or ‘power’

  • frequency (float or list of float, Hz) – freq corresponding to CST sim

  • telescope_name (str) – The instrument name

  • feed_name (str) – The name of the feed

  • feed_version (str) – The version of the feed

  • model_name (str) – Name for the model

  • model_version (str) – version of the model

  • feed_pol (str) – polarization of the feed (‘x’,’y’,’xx’,’yy’)

write_beam(beam, rms, counts, prefix)

Write the beam file out to .fits.

Parameters

prefix (str) – A string used to name and identify the output files.

Returns:

ECHO.plot_utils.cmap_discretize(cmap, N)

Return a discrete colormap from the continuous colormap cmap.

cmap: colormap instance, eg. cm.jet. N: number of colors.

Example

x = resize(arange(100), (5,100)) djet = cmap_discretize(cm.jet, 5) imshow(x, cmap=djet)

borrowed from http://scipy.github.io/old-wiki/pages/Cookbook/Matplotlib/ColormapTransformations

ECHO.plot_utils.grid_theta_phi_to_healpix(theta, phi, inbeam)
inputs:

theta (angle down from pixel 0, deg) phi (CW longitude angle, deg) inbeam: input beam values matching the corresponding theta and phi coords

ECHO.plot_utils.grid_to_healpix(lats, lons, alts, rx, lat0, lon0, nside=8)
input:

lats (deg) lons (deg) alts (m) (relative) rx: power in dB lat0: lat of rx ant (deg) lon0: lon of rx ant nside: of healpix map

class ECHO.plot_utils.nf(x=0, /)
ECHO.plot_utils.rotate_hpm(hpm, rot_phi, rot_theta, pol='EW')

rotate hpm about phi, then theta (degrees) if pol=EW theta is rotated about the X axis (default) if pol=NS theta is rotated about the Y axis

ECHO.plot_utils.rotate_hpm_old(hpm, angle, theta_angle=0)

rotate hpm angle degrees around the zero pixel (ie around the north pole)

ECHO.read_utils.CST_to_hp(beamfile, outfile, nside=8, rot=0, zflip=False)

Reads in a ASCII formatted CST export file and returns a healpix map. Also saves a .fits file to the current directory. This function is an adaptation of CST_to_healpix.py in the ECHO github. beamfile = CST export file outfile = name of the generated fits file, string nside = number of sides per healpix pixel, must be 2^n int, 8 is typical rot = rotates around the pole by 90deg*rot zflip = inverts the Z axis

ECHO.read_utils.channel_select(freqs, rxspectrum, channel)
input:

freqs: measured frequences in MHz rxspectrum: power in volt^2 shape(len(times),len(freqs)) channel: give a channel as an int or a float frequency in MHz

Returns

a single vector ntimes long

ECHO.read_utils.concat_times(Ts)

input a list of astropy time vectors

ECHO.read_utils.flag_angles(angletimes, angles, sigma=2)
input:

angletimes:astropy.time.Time vector angles: (1,len(angletimes))

sigma: flag values more than this many sigmas above the mean

Returns

mask times during which angles are bad

ECHO.read_utils.flag_waypoints(postimes, waypoint_times)
input:

postimes: astropy.time.Time vector matching GPS solutions waypoint_times: astropy.time.Time entries matching times reached wypts

Returns

flags on the postimes time base (ie matching len(postimes))

ECHO.read_utils.interp_rx(postimes, rxtimes, rx)
input:

postimes: astropy.Time.Time vector (output points) rxtime: astropy.time.Time vector (input points) Assumes that both position and spectrum data have been properly flagged and that the flags match between the two

Returns

interpolation of the rx power to the gps times

Note: this is just a general interpolation function that uses astropy times

and can be used for anything

ECHO.read_utils.mission_endpoint_flagging(pos_data, wpt_data)

Read in position and waypoint array, flag mission endpoints and return valid mission data.

Parameters

  • pos_data – the ulog to be converted.

  • wpt_data –

Returns

array of flagged data. mission_data: array of valid mission data.

Return type

flagged_data

ECHO.read_utils.read_CST_puv(CST_txtfile, beam_type, frequency, telescope_name, feed_name, feed_version, model_name, model_version, feed_pol)

Reads in a ASCII formatted CST export file and returns a beam model using pyuvbeam.

Inputs:

CST_txtfile: CST export file beam_type (str): efield or power frequency (list, Hz): our reference frequency telescope_name (str): The instrument name feed_name (str): The name of the feed feed_version (str): The version of the feed model_name (str): Name for the model model_version (str): version of the model feed_pol (str): polarization of the feed (‘x’,’y’,’xx’,’yy’)

ECHO.read_utils.read_h5(dataFile)

Read in receiver data file, put them into appropriate arrays

Input:

target_data (HDF5 data file): the datafile for the received power for the target antenna, saved in in h5 format.

Output:

dataDict: A dictionary containing the observation data. Includes observations, tunings, times, XX and YY polarizations, frequencies

ECHO.read_utils.read_tlog_txt(tlog)

Read in text files converted from tlogs, put them into appropriate arrays.

Parameters

tlog (int) – the text tlog to be read.

Returns

waypoints. global_array: global position. local_array: local position. gps_array: gps raw data.

Return type

wpt_array

ECHO.read_utils.read_ulog(ulog, output=None, messages='vehicle_global_position,vehicle_local_position,vehicle_gps_position')

Read in ulog file, put them into appropriate arrays, then save to .csv

Input:

ulog (int): the ulog to be converted.

Output:

global_array: global position. local_array: local position. gps_array: gps raw data.

ECHO.read_utils.write_map(filename, M)

write out a masked healpix map with the correct fill values

ECHO.time_utils.DatetimetoUnix(data)

Function to convert timestamps to unix time through an array.

Parameters

logged_data (array) – array of data including timestamps in the first column.

Returns

an array of the same shape as the input array, with timestamps in unix format.

Return type

timeconv_data