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ASA_WS__BP: ASAR Wide Swath Browse Image
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ASA_WV__0P: ASAR Wave Mode Level 0
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ASA_EC__0P: ASAR Level 0 External Characterization
ASA_APV_0P: ASAR Alternating Polarization Level 0 (Cross polar V)
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ASA_IMS_1P: ASAR Image Mode Single Look Complex
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ASA_GM1_1P: ASAR Global Monitoring Mode Image
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6.6.7 Chirp parameters

The chirp parameters derived from the calibration pulses may be updated more than once per product, or slice . Each update is stamped with the zero Doppler time to which the update applies, the swath to which it applies, and polarisation of the image
to which it applies. This time stamping allows for unambiguous recording of the chirp parameters, which were used for at any part of the image (for both MDS 1 and MDS 2 for Alternating Polarisation (AP) products) and for any beam . The coefficients continue to apply until a new update is made, and new values added to the ADS with a new time stamp. The contents of each update (each update is a single ADSR within the ADS) are as provided in the ASAR_Chirp_ADSR table, provided below.

Note, for Global Monitoring (GM) and Wide Swath (WS) products, there is a separate ADSR for each beam. The ADSRs are ordered according to their time stamps. If the time stamps of several ADSRs are identical, the ADSRs are ordered by beam number from SS1 to SS5.


Table 6.43 Chirp parameters

Chirp parameters

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

Always set to zero for this ADSR

flag 1 BooleanFlag 1 byte(s)
2 swath
Beam ID

SS1, SS2, SS3, SS4, or SS5 for WS and GM images. Set to NS�� for AP, IM, and WV images.

ascii 1 AsciiString 3 byte(s)
3 polar
Tx/Rx polarisation

H/H, H/V, V/V, or V/H

ascii 1 AsciiString 3 byte(s)
4 chirp_width
3-dB pulse width of chirp replica cross-correlation function between reconstructed chirp and nominal chirp
samples 1 fl 4 byte(s)
5 chirp_sidelobe
First side lobe level of chirp replica cross-correlation function between reconstructed chirp and nominal chirp
dB 1 fl 4 byte(s)
6 chirp_islr
ISLR of chirp replica cross-correlation function between reconstructed chirp and nominal chirp
dB 1 fl 4 byte(s)
7 chirp_peak_loc
Peak location of cross-correlation function between reconstructed chirp and nominal chirp
samples 1 fl 4 byte(s)
8 re_chirp_power
Reconstrcted Chirp power
dB 1 fl 4 byte(s)
9 elev_chirp_power
Equivalent chirp Power
dB 1 fl 4 byte(s)
10 chirp_quality_flag
Reconstructed chirp exceeds quality thresholds. 0 = reconstructed chirp below quality thresholds, current chirp is the nominal chirp. 1 = reconstructed chirp above quality thresholds, current chirp is the reconstructed chirp.
flag 1 BooleanFlag 1 byte(s)
11 ref_chirp_power
Reference chirp Power
dB 1 fl 4 byte(s)
12 normalization_source
Normalization source REPLICA, REF0000, EQV0000, NONE0000
- 1 AsciiString 7 byte(s)
13 spare_1
Spare
- 1 SpareField 4 byte(s)
14 cal_pulse_info
This structure is repeated 32 times: once for each antenna row
- 32 cal_pulse_infoStruct 32*44.0 byte(s)
a max_cal
Max of Cal pulses 1, 2, and 3 amplitude
- 3 fl 3*4 byte(s)
b avg_cal
Average of Cal pulse 1, 2, and 3 amplitude over the 3 dB on either side of the max amplitude
- 3 fl 3*4 byte(s)
c avg_val_1a
Average of Cal pulse 1A over the sample window
- 1 fl 4 byte(s)
d phs_cal
Extracted phase for calibration pulse 1, 1A, 2, and 3
degrees 4 fl 4*4 byte(s)
15 spare_2
Spare
- 1 SpareField 16 byte(s)
Record Length : 1483

DS_NAME : Chirp parameters



Format Version 114.0