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.
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Table 6.43 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) |
DS_NAME : Chirp parameters
Format Version 114.0
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EO Data Access
