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ASA_WS__BP: ASAR Wide Swath Browse Image
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ASA_IMS_1P: ASAR Image Mode Single Look Complex
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ASA_WVS_1P: ASAR Wave Mode Imagette Cross Spectra
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6.6.16 SQ ADSRs

There are two Summary Quality (SQ) ADS s. The first contains information pertaining to MDS 1 and the second contains information pertaining to MDS 2. The format of each SQ ADS is identical, however the values may differ as each describes
a separate MDS.

The information contained in the SQ ADS is a summary of parameters used to establish the quality of the product. This includes Product Confidence Data (PCD) flags, the thresholds used to evaluate the flags, and numerical quality parameters.

For the basic image product, the SQ information ADS is updated once per product (i.e., updated once per slice for stripline ). Each ADSR is time stamped with the zero Doppler time at which it was issued. The SQ ADS is included in the inventory so
that the user may evaluate the quality of the product prior to ordering.

The product statistics which are evaluated at each time stamp (each ADSR) and the error message generated will be as follows.


Table 6.53 SQ ADSRs

SQ ADSRs

# Description Units Count Type Size
Data Record
0 zero_doppler_time
Zero doppler time at which Summary Quality information applies
MJD 1 mjd 12 byte(s)
1 attach_flag
Attachment Flag

Set to 1 if all MDSRs corresponding to this ADSR are blank, set to zero otherwise. This flag will always be zero because this ADSR is updated once per slice or scene. Therefore, if there are no MDSRs, this ADSR is not produced at all.

flag 1 BooleanFlag 1 byte(s)
2 input_mean_flag
Input data mean outside nominal range flag

0 = mean of I and Q input values are both within specified range from expected mean. For expected mean of x, the measured mean must fall between x-threshold to x+threshold. 1 = otherwise

flag 1 BooleanFlag 1 byte(s)
3 input_std_dev_flag
Input data standard deviation outside nominal range flag

0 = standard deviation values of I and Q input values are both within specified range of expected standard deviation. For expected std. dev. x, the measured std. dev. must fall between x-threshold to x+threshold. 1 = otherwise

flag 1 BooleanFlag 1 byte(s)
4 input_gaps_flag
Significant gaps in the input data flag

0 = number of input gaps <= threshold value 1 = number of input data gaps > threshold value.

flag 1 BooleanFlag 1 byte(s)
5 input_missing_lines_flag
Missing lines significant flag

0 = percentage of missing lines <= threshold value 1 = percentage of missing lines > threshold value. The number of missing lines is the number of lines missing from the input data, excluding data gaps.

flag 1 BooleanFlag 1 byte(s)
6 dop_cen_flag
Doppler Centroid Uncertain flag

0 = confidence measure >= specified value 1 = confidence measure < specified value. If more than one Doppler centroid estimation is performed in a slice, the flag is set if any confidence measure is less than the threshold.

flag 1 BooleanFlag 1 byte(s)
7 dop_amb_flag
Doppler ambiguity estimate uncertain flag

0 = confidence measure >= specified value 1 = confidence measure < specified value

flag 1 BooleanFlag 1 byte(s)
8 output_mean_flag
Output data mean outside nominal range flag

0 = mean of I and Q output values for SLC image or mean of detected pixels for a detected product, are both within specified range from expected mean. For expected mean of x, the measured mean must fall between x-threshold to x+threshold. 1= otherwise.

flag 1 BooleanFlag 1 byte(s)
9 output_std_dev_flag
Output data standard deviation outside nominal range flag

0 = mean of I and Q output values for SLC image or mean of detected pixels for a detected product, are both within specified range from expected mean. For expected mean of x, the measured mean must fall between x-threshold to x+threshold. 1 = otherwise

flag 1 BooleanFlag 1 byte(s)
10 chirp_flag
Chirp extraction failed or is of low quality flag

0 = able to reconstruct all chirps or chirp reconstruction not requested (nominal chirp used) AND all quality measures were acceptable. 1 = unable to reconstruct a chirp during processing and chirp reconstruction was requested or the quality is below the acceptable levels. When value = 1, (i.e. unable to reconstruct a chirp during processing and chirp reconstruction was requested or the quality is below the acceptable levels), PF-ASAR uses the nominal range pulse for processing and a nominal elevation beam scaling factor.

flag 1 BooleanFlag 1 byte(s)
11 missing_data_sets_flag
Data sets missing flag

0 = all data sets which are supposed to be in the product are present 1 = any data sets (including ADSs) are missing from the product which are supposed to be included under normal circumstances. When value = 1 (i.e any data sets, including ADSs, are missing from the product which are supposed to be included under normal circumstances), which data sets are missing can be determined by an examination of the DSDs in the SPH.

flag 1 BooleanFlag 1 byte(s)
12 invalid_downlink_flag
Invalid downlink parameters flag

0 = all parameters read from the downlinked data were valid 1 = displayed if any downlink parameter is out of range and therefore a default value has been used during processing.

flag 1 BooleanFlag 1 byte(s)
13 spare_1
Spare
- 1 SpareField 7 byte(s)
14 thresh_chirp_broadening
Threshold for setting the chirp quality flag.

Maximum percentage broadening permitted in cross-correlation pulse width compared to theoretical width.

% 1 fl 4 byte(s)
15 thresh_chirp_sidelobe
Threshold for setting the chirp quality flag

First sidelobe of the chirp cross correlation function

dB 1 fl 4 byte(s)
16 thresh_chirp_islr
Threshold for setting the chirp quality flag

ISLR of the chirp cross correlation function

dB 1 fl 4 byte(s)
17 thresh_input_mean
Threshold for setting the mean of input data quality flag

For an expected mean value of x, this is the value T, such that the measured mean must fall between the x-T and x+T.

- 1 fl 4 byte(s)
18 exp_input_mean
Expected mean input value for this product for both I and Q.
- 1 fl 4 byte(s)
19 thresh_input_std_dev
Threshold for setting the standard deviation of input data quality flag

For an expected standard deviation value of y, this is the value D, such that the measured standard deviation must fall between the y-D and y+D.

- 1 fl 4 byte(s)
20 exp_input_std_dev
Expected input std. dev. for this product for both I and Q.
- 1 fl 4 byte(s)
21 thresh_dop_cen
Threshold for setting the Doppler Centroid quality flag

Threshold for Doppler Centroid confidence

- 1 fl 4 byte(s)
22 thresh_dop_amb
Threshold for setting the Doppler Centroid ambiguity quality flag

Threshold for setting the Doppler Centroid ambiguity confidence flag

- 1 fl 4 byte(s)
23 thresh_output_mean
Threshold for setting the mean of output data quality flag

For an expected mean value of x, this is the value T, such that the measured mean must fall between the x-T and x+T.

- 1 fl 4 byte(s)
24 exp_output_mean
Expected mean output value for this product. For an SLC product this is the expected mean of both the I and Q values.
- 1 fl 4 byte(s)
25 thresh_output_std_dev
Threshold for setting the standard deviation of output data quality flag

For an expected standard deviation value of y, this is the value D, such that the measured standard deviation must fall between the y-D and y+D.

- 1 fl 4 byte(s)
26 exp_output_std_dev
Expected output std. dev. for this product. For an SLC product this is the expected output std. dev. for both I and Q values.
- 1 fl 4 byte(s)
27 thresh_input_missing_lines
Threshold for setting the missing lines quality flag

Maximum percentage of missing lines to total lines.

% 1 fl 4 byte(s)
28 thresh_input_gaps
Threshold for setting the missing gaps quality flag

Maximum number of missing gaps allowed.

- 1 fl 4 byte(s)
29 lines_per_gaps
Number of missing lines which constitute a gap
lines 1 ul 4 byte(s)
30 spare_2
Spare
- 1 SpareField 15 byte(s)
31 input_mean
Input data mean

I channel, Q channel

- 2 fl 2*4 byte(s)
32 input_std_dev
Input data standard deviation

I channel, Q channel

- 2 fl 2*4 byte(s)
33 num_gaps
Number of gaps

Composed of a predetermined number of consecutive missing lines

- 1 fl 4 byte(s)
34 num_missing_lines
Number of missing lines

Excluding gaps

- 1 fl 4 byte(s)
35 output_mean
Output data mean

For SLC products, first value is for the I channel, second is for the Q channel. For detected products, second value is set to zero

- 2 fl 2*4 byte(s)
36 output_std_dev
Output data standard deviation

For SLC products, first value is for the I channel, second is for the Q channel. For detected products, second value is set to zero

- 2 fl 2*4 byte(s)
37 tot_errors
Total number of errors detected in isp headers
- 1 ul 4 byte(s)
38 Spare_3
Spare
- 1 SpareField 16 byte(s)
Record Length : 170

DS_NAME : SQ ADSRs



Format Version 114.0  

Note : Each of these fields (#15, 16 and 17 ) will all contain values for the " Threshold for setting the chirp quality flag " . A chirp is reconstructed from information in the downlink , which is then validated against a theortetical chirp, which generates a number of quality measures. These quality measures are then compared to thresholds to determine if the reconstructed chirp is OK