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ASAR Data Formats Products
Geolocation Grid ADSRs
Doppler Centroid parameters
Chirp parameters
Antenna Elevation pattern
ASAR external characterization data
ASAR external calibration data
Level 0 SPH
Level 0 MDSR
SPH for auxiliary data with N=1 DSDs
Wave Mode Geolocation ADS
ASAR Wave Mode Products Base SPH
Slant Range to Ground Range conversion parameters
Measurement Data Set containing spectra. 1 MDSR per spectra.
Ocean Wave Spectra
Map Projection parameters
ASAR Image Products SPH
Measurement Data Set 1
Auxilliary Products
ASA_XCH_AX: ASAR External characterization data
ASA_XCA_AX: ASAR External calibration data
ASA_INS_AX: ASAR Instrument characterization
ASA_CON_AX: ASAR Processor Configuration
Browse Products
ASA_WS__BP: ASAR Wide Swath Browse Image
ASA_IM__BP: ASAR Image Mode Browse Image
ASA_GM__BP: ASAR Global Monitoring Mode Browse Image
ASA_AP__BP: ASAR Alternating Polarization Browse Image
Level 0 Products
ASA_WV__0P: ASAR Wave Mode Level 0
ASA_WS__0P: ASAR Wide Swath Mode Level 0
ASA_MS__0P: ASAR Level 0 Module Stepping Mode
ASA_IM__0P: ASAR Image Mode Level 0
ASA_GM__0P: ASAR Global Monitoring Mode Level 0
ASA_EC__0P: ASAR Level 0 External Characterization
ASA_APV_0P: ASAR Alternating Polarization Level 0 (Cross polar V)
ASA_APH_0P: ASAR Alternating Polarization Level 0 (Cross polar H)
ASA_APC_0P: ASAR Alternating Polarization Level 0 (Copolar)
Level 1 Products
ASA_IMS_1P: ASAR Image Mode Single Look Complex
ASA_IMP_1P: ASAR Image Mode Precision Image
ASA_IMM_1P: ASAR Image Mode Medium Resolution Image
ASA_IMG_1P: ASAR Image Mode Ellipsoid Geocoded Image
ASA_GM1_1P: ASAR Global Monitoring Mode Image
ASA_APS_1P: ASAR Alternating Polarization Mode Single Look Complex
ASA_APP_1P: ASAR Alternating Polarization Mode Precision Image
ASA_APM_1P: ASAR Alternating Polarization Medium Resolution Image product
ASA_WSS_1P: Wide Swath Mode SLC Image
ASA_WVS_1P: ASAR Wave Mode Imagette Cross Spectra
ASA_WSM_1P: ASAR Wide Swath Medium Resolution Image
ASA_APG_1P: ASAR Alternating Polarization Ellipsoid Geocoded Image
Level 2 Products
ASA_WVW_2P: ASAR Wave Mode Wave Spectra
ASAR Glossary Terms
Sea Ice Glossary
Land Glossary
Oceans Glossary
Geometry Glossary
ASAR Instrument Glossary
Acronyms and Abbreviations
ASAR Frequently Asked Questions
The ASAR Instrument
Instrument Characteristics and Performance
Inflight Performance Verification
Preflight Characteristics and Expected Performance
Instrument Description
Internal Data Flow
ASAR Instrument Functionality
Payload Description and Position on the Platform
ASAR Products and Algorithms
Auxiliary Products
Common Auxiliary Data Sets
Auxiliary Data Sets for Level 1B Processing
Summary of Auxiliary Data Sets
Instrument-specific Topics
Level 2 Product and Algorithms
Level 2 Product
ASAR Level 2 Algorithms
Level 1B Products
ASAR Level 0 Products
Level 0 Instrument Source Packet Description
Product Evolution History
Definitions and Conventions
Organisation of Products
ASAR Data Handling Cookbook
Hints and Algorithms for Higher Level Processing
Hints and Algorithms for Data Use
ASAR Characterisation and Calibration
The Derivation of Backscattering Coefficients and RCSs in ASAR Products
External Characterisation
Internal Calibration
Pre-flight Characterisation Measurements
ASAR Latency Throughput and Data Volume
Data Volume
Products and Algorithms Introduction
Child Products
The ASAR User Guide
Image Gallery
Further Reading
How to Use ASAR Data
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How to Choose ASAR Data
Special Features of ASAR
Geophysical Coverage
Principles of Measurement
Scientific Background
Geophysical Measurements
ASAR Product Handbook
ASAR instrument characterization data
Wave Mode processing parameters
ASAR processor configuration data
Main Processing parameters
ASA_WVI_1P: ASAR Wave Mode SLC Imagette and Imagette Cross Spectra
Product Terms
RADAR and SAR Glossary
Level 1B Products
Summary of Applications vs Products
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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
- 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
- 1 SpareField 16 byte(s)
Record Length : 1483

DS_NAME : Chirp parameters

Format Version 114.0