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6.6.15 Measurement Data Set containing spectra. 1 MDSR per spectra.

This Measurement Data Set (MDS) contains the cross spectrum of the imagette . There is one MDSR per wave cell. The format of each MDSR is described in the table below:


Table 6.52 Measurement Data Set containing spectra. 1 MDSR per spectra

Measurement Data Set containing spectra. 1 MDSR per spectra.

# Description Units Count Type Size
Data Record
0 zero_doppler_time
First Zero Doppler Azimuth time of the wave cellTime of first range line in the SLC Imagette MDS described by this data set
MJD 1 mjd 12 byte(s)
1 quality_flag
Quality Indicator (-1 for blank MDSR, 0 otherwise)
flag 1 BooleanFlag 1 byte(s)
2 range_spectral_res
Range bin size of the cartesian cross spectrum
- 1 fl 4 byte(s)
3 az_spectral_res
Azimuth bin size of the cartesian cross spectrum
- 1 fl 4 byte(s)
4 spare_1
Spare
- 1 SpareField 4 byte(s)
5 spec_tot_energy
Spectrum Total Energy
- 1 fl 4 byte(s)
6 spec_max_energy
Spectrum Max Energy
- 1 fl 4 byte(s)
7 spec_max_dir
Direction of Spectrum Max (deg)

On higher resolution grid. Direction is counter-clockwise from satellite track heading

deg 1 fl 4 byte(s)
8 spec_max_wl
Wavelength of Spectrum Max (m)

On higher resolution grid

m 1 fl 4 byte(s)
9 clutter_noise
Clutter Noise
- 1 fl 4 byte(s)
10 az_cutoff
Azimuthal Clutter Cut-off length (m)
m 1 fl 4 byte(s)
11 num_iterations
Number of iterations to compute Azimuthal Clutter Cut-off
- 1 fl 4 byte(s)
12 range_offset
Range offset of peak of cross covariance function (m)
m 1 fl 4 byte(s)
13 ax_offset
Azimuth offset of peak of cross covariance function (m)
m 1 fl 4 byte(s)
14 cc_range_res
Range bin size of cross covariance function (m)
m 1 fl 4 byte(s)
15 cc_azimuth_res
Azimuth bin size of cross covariance function (m)
m 1 fl 4 byte(s)
16 sublook_means
1st and last Sub-look Image Means
- 2 fl 2*4 byte(s)
17 sublook_variance
1st and last Sub-look Image Variance
- 2 fl 2*4 byte(s)
18 sublook_skewness
1st and last Sub-look Image Skewness
- 2 fl 2*4 byte(s)
19 sublook_kurtosis
1st and last Sub-look Image Kurtosis
- 2 fl 2*4 byte(s)
20 range_sublook_detrend_coeff
1st and last Sub-look de-trend coefficient in range
- 2 fl 2*4 byte(s)
21 az_sublook_detrend_coeff
1st and last Sub-look de-trend coefficient in azimuth
- 2 fl 2*4 byte(s)
22 min_imag
Min value of Imaginary part of cross spectrum
- 1 fl 4 byte(s)
23 max_imag
Max value of Imaginary part of cross spectrum
- 1 fl 4 byte(s)
24 min_real
Min value of Real part of cross spectrum
- 1 fl 4 byte(s)
25 max_real
Max value of Real part of cross spectrum
- 1 fl 4 byte(s)
26 spare_2
Spare
- 1 SpareField 64 byte(s)
27 real_spectra
Real part of cross spectra polar grid

Number of bins in wavelength and direction defined in SPH (nominally 24 by 36). However, only 0 to 180 degree of the spectrum need be supplied (24 by 18). Arranged as: 24 wavelength values for [-5,5] deg. sector, 24 values for [5,15] deg. sector, ..., 24 values for [165,175] deg. sector, in the counter-clockwise direction. The 24 values for each sector are given in order from longest to shortest wavelength.

- uc 1 byte(s)
28 imag_spectra
Complex part of cross spectra polar grid

Number of bins in wavelength and direction defined in SPH (nominally 24 by 36). However, only 0 to 180 degree of the spectrum need be supplied (24 by 18). Arranged as: 24 wavelength values for [-5,5] deg. sector, 24 values for [5,15] deg. sector, ..., 24 values for [165,175] deg. sector, in the counter-clockwise direction. The 24 values for each sector are given in order from longest to shortest wavelength.

- uc 1 byte(s)
Record Length : 195

DS_NAME : Measurement Data Set containing spectra. 1 MDSR per spectra.



Format Version 114.0  

Notes:

The cross spectrum is given in the MDS in complex form on a polar grid. The size of the cross spectrum grid is given in the SPH . Typically this will be 24 by 36 bins in wavelength and direction respectively. As the real part of the polar spectrum is symmetric, and the imaginary part is anti-symmetric, only 0 to 180 need to be given in order to reconstruct the entire spectrum (i.e., only 18 directional bins).

The cross spectrum values shall be stored in an unsigned integer format, each part linearly scaled to the maximum and minimum values of the representation (e.g., 0 to 255). The original maximum and minimum values for each part is reported.

The cross spectrum statistics are derived from a high-resolution polar spectrum, prior to encoding for output to the product, or at other intermediate stages of the processing.

If the processor is unable to produce the cross spectra for a given wave cell, the MDSR is time stamped with the time that the cross spectra would have corresponded to, the Quality Flag is set to -1, and the MDSR data fields are all set to zero.

The format of the Wave Mode cross spectrum product is given in the section entitled " Wave Spectra " .1.59