bfiq v0.5¶
This is the most up to date version of this file format produced by Borealis version 0.5, the current version.
For data files from previous Borealis software versions, see here.
The pydarn format class for this format is BorealisBfiq found in the borealis_formats.
The bfiq format is intended to hold beamformed I and Q data for the main and interferometer arrays. The data is not averaged.
Both site files and array-restructured files exist for this file type. Both are described below.
bfiq array files¶
Array restructured files are produced after the radar has finished writing a file and contain record data in multi-dimensional arrays so as to avoid repeated values, shorten the read time, and improve human readability. Fields that are unique to the record are written as arrays where the first dimension is equal to the number of records recorded. Other fields that are unique to the slice or experiment (and are therefore repeated for all records) are written only once.
The group names in these files are the field names themselves, greatly reducing the number of group names in the file when compared to site files and making the file much more human readable.
The naming convention of the bfiq array-structured files are:
[YYYYmmDD].[HHMM].[SS].[station_id].[slice_id].bfiq.hdf5
For example: 20191105.1400.02.sas.0.bfiq.hdf5
This is the file that began writing at 14:00:02 UT on November 5 2019 at the Saskatoon site, and it provides data for slice 0 of the experiment that ran at that time. It has been array restructured because it does not have a .site designation at the end of the filename.
These files are zlib compressed which is native to hdf5 and no decompression is necessary before reading using your hdf5 library.
The file fields in the bfiq array files are:
FIELD NAME
type
[dimensions]
|
description |
|---|---|
antenna_arrays_order
unicode
[num_antenna_arrays]
|
States what order the data is in and
describes the data layout for the
num_antenna_arrays data dimension
|
beam_azms
float64
[num_records x
max_num_beams]
|
A list of the beam azimuths for each beam
in degrees off boresite. Note that this
is padded with zeroes for any record
which has num_beams less than the
max_num_beams. The num_beams field should
be used to read the correct number of
beams for each record.
|
beam_nums
uint32
[num_records x
max_num_beams]
|
A list of beam numbers used in this slice
in this record. Note that this is padded
with zeroes for any record which has
num_beams less than the max_num_beams.
The num_beams field should be used to
read the correct number of beams for each
record.
|
blanked_samples
uint32
[num_records x
max_num_blanked_samples ]
|
Samples that should be blanked because
they occurred during transmission times,
given by sample number (index into
decimated data). Can differ from the
pulses array due to multiple slices in a
single sequence and can differ from
record to record if a new slice is added.
|
borealis_git_hash
unicode
|
Identifies the version of Borealis that
made this data. Contains git commit hash
characters. Typically begins with the
latest git tag of the software.
|
data
complex64
[num_records x
num_antenna_arrays x
max_num_sequences x
max_num_beams x
num_samps]
|
A set of samples (complex float) at given
sample rate. Note that records that do not
have num_sequences = max_num_sequences or
num_beams = max_num_beams will have
padded zeros. The num_sequences and
num_beams arrays should be used to
determine the correct number of sequences
and beams to read for the record.
|
data_descriptors
unicode
[5]
|
Denotes what each data dimension
represents. = ‘num_records’,
‘num_antenna_arrays’,
‘max_num_sequences’, ‘max_num_beams’,
‘num_samps’
|
data_normalization_factor
float32
|
Scale of all the filters used,
multiplied, for a total scale to
normalize the data by.
|
experiment_comment
unicode
|
Comment provided in experiment about the
experiment as a whole.
|
experiment_id
int64
|
Number used to identify the experiment.
|
experiment_name
unicode
|
Name of the experiment file.
|
first_range
float32
|
Distance to use for first range in km.
|
first_range_rtt
float32
|
Round trip time of flight to first range
in microseconds.
|
freq
uint32
|
The frequency used for this experiment,
in kHz. This is the frequency the data
has been filtered to.
|
int_time
float32
[num_records]
|
Integration time in seconds.
|
intf_antenna_count
uint32
|
Number of interferometer array antennas
|
lags
uint32
[number of lags, 2]
|
The lags created from two pulses in the
pulses array. Values have to be from
pulses array. The lag number is lag[1] -
lag[0] for each lag pair.
|
main_antenna_count
uint32
|
Number of main array antennas
|
noise_at_freq
float64
[num_records x
max_num_sequences]
|
Noise at the receive frequency, with
dimension = number of sequences.
20191114: not currently implemented and
filled with zeros. Still a TODO. Note
that records that do not have
num_sequences = max_num_sequences will
have padded zeros. The num_sequences
array should be used to determine the
correct number of sequences to read for
the record.
|
num_beams
uint32
[num_records]
|
The number of beams calculated for each
record. Allows the user to correctly read
the data up to the correct number and
remove the padded zeros in the data
array.
|
num_blanked_samples
uint32
[num_records]
|
The number of blanked samples for each
record.
|
num_ranges
uint32
|
Number of ranges to calculate
correlations for.
|
num_samps
uint32
|
Number of samples in the sampling
period. Each sequence has its own
sampling period. Will also be provided
as the last data_dimension value.
|
num_sequences
int64
[num_records]
|
Number of sampling periods (equivalent to
number sequences transmitted) in the
integration time for each record. Allows
the user to correctly read the data up to
the correct number and remove the padded
zeros in the data array.
|
num_slices
int64
[num_records]
|
Number of slices used simultaneously in
the record by the experiment. If more
than 1, data should exist in another file
for the same time period as that record
for the other slice.
|
pulse_phase_offset
float32
[number of pulses]
|
For pulse encoding phase, in degrees
offset. Contains one phase offset per
pulse in pulses.
|
pulses
uint32
[number of pulses]
|
The pulse sequence in units of the
tau_spacing.
|
range_sep
float32
|
Range gate separation (conversion from
time (1/rx_sample_rate) to equivalent
distance between samples), in km.
|
rx_sample_rate
float64
|
Sampling rate of the samples in this
file’s data in Hz.
|
samples_data_type
unicode
|
C data type of the samples, provided for
user friendliness. = ‘complex float’
|
scan_start_marker
bool
[num_records]
|
Designates if the record is the first in
a scan (scan is defined by the
experiment).
|
scheduling_mode
unicode
|
The mode being run during this time
period (ex. ‘common’, ‘special’,
‘discretionary’).
|
slice_comment
unicode
|
Additional text comment that describes
the slice written in this file. The slice
number of this file is provided in the
filename.
|
slice_id
uint32
|
The slice id of this file.
|
slice_interfacing
unicode
[num_records]
|
The interfacing of this slice to
other slices for each record. String
representation of the python dictionary
of {slice : interface_type, … }. Can
differ between records if slices updated.
|
sqn_timestamps
float64
[num_records x
max_num_sequences]
|
A list of GPS timestamps corresponding to
the beginning of transmission for each
sampling period in the integration time.
These timestamps come back from the USRP
driver and the USRPs are GPS disciplined
and synchronized using the Octoclock.
Provided in milliseconds since epoch.
Note that records that do not have
num_sequences = max_num_sequences will
have padded zeros. The num_sequences
array should be used to determine the
correct number of sequences to read for
the record.
|
station
unicode
|
Three-letter radar identifier.
|
tau_spacing
uint32
|
The minimum spacing between pulses in
microseconds. Spacing between pulses is
always a multiple of this.
|
tx_pulse_len
uint32
|
Length of the transmit pulse in
microseconds.
|
bfiq site files¶
Site files are produced by the Borealis code package and have the data in a record by record style format. In site files, the hdf5 group names (ie record names) are given as the timestamp in ms past epoch of the first sequence or sampling period recorded in the record.
The naming convention of the bfiq site-structured files are:
[YYYYmmDD].[HHMM].[SS].[station_id].[slice_id].bfiq.hdf5.site
For example: 20191105.1400.02.sas.0.bfiq.hdf5.site This is the file that began writing at 14:00:02 UT on November 5 2019 at the Saskatoon site, and it provides data for slice 0 of the experiment that ran at that time.
These files are often bzipped after they are produced.
The file fields under the record name in bfiq site files are:
Field name
type
|
description |
|---|---|
antenna_arrays_order
[unicode, ]
|
States what order the data is in and
describes the data layout for the
num_antenna_arrays data dimension
|
beam_azms
[float64, ]
|
A list of the beam azimuths for each
beam in degrees off boresite.
|
beam_nums
[uint32, ]
|
A list of beam numbers used in this slice
in this record.
|
blanked_samples
[uint32, ]
|
Samples that should be blanked because
they occurred during transmission times,
given by sample number (index into
decimated data). Can differ from the
pulses array due to multiple slices in a
single sequence.
|
borealis_git_hash
unicode
|
Identifies the version of Borealis that
made this data. Contains git commit hash
characters. Typically begins with the
latest git tag of the software.
|
data
[complex64, ]
|
A contiguous set of samples (complex
float) at given sample rate. Needs to be
reshaped by data_dimensions to be
correctly read.
|
data_descriptors
[unicode, ]
|
Denotes what each data dimension
represents. = ‘num_antenna_arrays’,
‘num_sequences’, ‘num_beams’, ‘num_samps’
for bfiq
|
data_dimensions
[uint32, ]
|
The dimensions in which to reshape the
data. Dimensions correspond to
data_descriptors.
|
data_normalization_factor
float32
|
Scale of all the filters used, multiplied
for a total scale to normalize the data
by.
|
experiment_comment
unicode
|
Comment provided in experiment about the
experiment as a whole.
|
experiment_id
int64
|
Number used to identify the experiment.
|
experiment_name
unicode
|
Name of the experiment file.
|
first_range
float32
|
Distance to use for first range in km.
|
first_range_rtt
float32
|
Round trip time of flight to first range
in microseconds.
|
freq
uint32
|
The frequency used for this experiment,
in kHz. This is the frequency the data
has been filtered to.
|
int_time
float32
|
Integration time in seconds.
|
intf_antenna_count
uint32
|
Number of interferometer array antennas
|
lags
[[uint32, ], ]
|
The lags created from two pulses in the
pulses array. Dimensions are number of
lags x 2. Values have to be from pulses
array. The lag number is lag[1] - lag[0]
for each lag pair.
|
main_antenna_count
uint32
|
Number of main array antennas
|
noise_at_freq
[float64, ]
|
Noise at the receive frequency, with
dimension = number of sequences.
20191114: not currently implemented and
filled with zeros. Still a TODO.
|
num_ranges
uint32
|
Number of ranges to calculate
correlations for.
|
num_samps
uint32
|
Number of samples in the sampling
period. Each sequence has its own
sampling period. Will also be provided
as the last data_dimension value.
|
num_sequences
int64
|
Number of sampling periods (equivalent to
number sequences transmitted) in the
integration time.
|
num_slices
int64
|
Number of slices used simultaneously in
this record by the experiment. If more
than 1, data should exist in another file
for this time period for the other slice.
|
pulse_phase_offset
[float32, ]
|
For pulse encoding phase, in degrees
offset. Contains one phase offset per
pulse in pulses.
|
pulses
[uint32, ]
|
The pulse sequence in units of the
tau_spacing.
|
range_sep
float32
|
Range gate separation (conversion from
time (1/rx_sample_rate) to equivalent
distance between samples), in km.
|
rx_sample_rate
float64
|
Sampling rate of the samples in this
file’s data in Hz.
|
samples_data_type
unicode
|
C data type of the samples, provided for
user friendliness. = ‘complex float’
|
scan_start_marker
bool
|
Designates if the record is the first in
a scan (scan is defined by the
experiment).
|
scheduling_mode
unicode
|
The mode being run during this time
period (ex. ‘common’, ‘special’,
‘discretionary’).
|
slice_comment
unicode
|
Additional text comment that describes
the slice written in this file.
|
slice_id
uint32
|
The slice id of this file.
|
slice_interfacing
unicode
|
The interfacing of this slice to
other slices. String representation of
the python dictionary of
{slice : interface_type, … }
|
sqn_timestamps
[float64, ]
|
A list of GPS timestamps corresponding to
the beginning of transmission for each
sampling period in the integration time.
These timestamps come from the USRP
driver and the USRPs are GPS disciplined
and synchronized using the Octoclock.
Provided in milliseconds since epoch.
|
station
unicode
|
Three-letter radar identifier.
|
tau_spacing
uint32
|
The minimum spacing between pulses in
microseconds. Spacing between pulses is
always a multiple of this.
|
tx_pulse_len
uint32
|
Length of the transmit pulse in
microseconds.
|
Site/Array Restructuring¶
File restructuring to array files is done using an additional code package. Currently, this code is housed within pyDARN. It is expected that this code will be separated to its own IO code package in the near future.
The site to array file restructuring occurs in the borealis BaseFormat _site_to_array class method, and array to site restructuring is done in the same class _array_to_site method. Both can be found here.
bfiq to iqdat SDARN (DMap) Conversion¶
Conversion to SDARN IO (DMap iqdat) is available but can fail based on experiment complexity. The conversion also reduces the precision of the data due to conversion from complex floats to int of all samples. Similar precision is lost in timestamps.
HDF5 is a much more user-friendly format and we encourage the use of this data if possible. Please reach out if you have questions on how to use the Borealis bfiq files.
The mapping from bfiq to iqdat dmap files is completed as follows: