def reform_waveform(self, mds_ra2, mds_wfm18hz):
# Relevant field names
wfm_tag = "average_wfm_if_corr_ku"
tracker_range_tag = "18hz_tracker_range_no_doppler_ku"
doppler_tag = "18Hz_ku_range_doppler"
slope_tag = "18Hz_ku_range_doppler_slope"
# First get the echo power
n_range_bins = 128
n = self.n_records * self.n_blocks
self.power = np.ndarray(shape=(n, n_range_bins), dtype=np.float32)
for dsd in range(self.n_records):
for block in range(self.n_blocks):
i = dsd*self.n_blocks + block
self.power[i, :] = mds_wfm18hz[dsd].wfm[block][wfm_tag]
# Calculate the window delay for each 18hz waveform
range_info = get_structarr_attr(mds_ra2, "range_information")
range_corr = get_structarr_attr(mds_ra2, "range_correction")
tracker_range = get_structarr_attr(
range_info, tracker_range_tag, flat=True)
doppler_correction = get_structarr_attr(
range_corr, doppler_tag, flat=True)
slope_correction = get_structarr_attr(
range_corr, slope_tag, flat=True)
# Compute the window delay (range to first range bin)
# given in meter (not in seconds)
# XXX: Add the instrumental range correction for ku?
self.window_delay_m = get_envisat_window_delay(
tracker_range, doppler_correction, slope_correction)
# Compute the range value for each range bin of the 18hz waveform
# XXX: Might want to set the range bins automatically
self.range = get_envisat_wfm_range(self.window_delay_m, n_range_bins)
def _transfer_waveform_collection(self):
""" Transfers the waveform data (power & range for each range bin) """
# Transfer the reformed 18Hz waveforms
# "waveform samples (I2+Q2, 1/2048 FFT power unit): 18 Hz Ku band";
# "the echo is corrected for the intermediate frequency filter effect";
wfm_power = self.sgdr.waveform_fft_20_ku
n_records, n_range_bins = wfm_power.shape
# Compute the window delay and the range values
window_delay_m = get_envisat_window_delay(
self.sgdr.tracker_range_20_ku,
self.sgdr.dop_cor_20_ku,
self.sgdr.dop_slope_cor_20_ku,
nominal_tracking_bin=self.cfg.nominal_tracking_bin,
bin_width_meter=self.cfg.bin_width_meter)
# Compute the range value for each range bin of the 18hz waveform
wfm_range = get_envisat_wfm_range(
window_delay_m, n_range_bins,
bin_width_meter=self.cfg.bin_width_meter)
# Transfer data to the waveform group
self.l1.waveform.set_waveform_data(wfm_power, wfm_range, self.cfg.radar_mode)
# Set valid flag to exclude calibration data
# (see section 3.5 of Reaper handbook)
valid_flag = np.logical_not(self.sgdr.waveform_fault_id_20.astype(bool))
self.l1.waveform.set_valid_flag(valid_flag)