19-Mar-2010

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The ASAR User Guide

ASAR Products and Algorithms

The ASAR Instrument

ASAR Frequently Asked Questions

ASAR Glossary Terms

ASAR Data Formats Products

Credits

Services

Frequently asked questions

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Index

1 The ASAR User Guide

1.1 How to Choose ASAR Data

1.1.1 Geophysical Measurements

1.1.2 Scientific Background

1.1.2.1 Radar Imaging

1.1.2.1.1 Polarisation

1.1.2.1.2 Backscatter

1.1.2.2 Real Aperture Radar (RAR)

1.1.2.2.1 Spatial Resolution

1.1.2.2.2 Range Resolution

1.1.2.2.3 Azimuth Resolution

1.1.2.3 Synthetic Aperture Radar (SAR)

1.1.2.4 Image Interpretation

1.1.2.4.1 Geometric Characteristics

1.1.2.4.2 Electrical Characteristics

1.1.2.4.3 Responses of Soil, Vegetation, Mountains, Water and Ice

1.1.2.4.3.1 Soil

1.1.2.4.3.2 Vegetation

1.1.2.4.3.3 Mountains

1.1.2.4.3.4 Water and Ice

1.1.2.5 General Rules for SAR Image Interpretation

1.1.2.6 References

1.1.3 Principles of Measurement

1.1.4 Geophysical Coverage

1.1.5 Special Features of ASAR

1.1.5.1 Dual Polarisation

1.1.5.2 Selectable Incidence Angles

1.1.5.3 Wide Area Coverage and Frequency of Coverage

1.1.5.4 Interferometry

1.1.5.4.1 Principles

1.1.5.4.2 Across-track Interferometry (InSAR)

1.1.5.4.3 Along-track Interferometry

1.1.5.4.4 Differential Interferometry (D-InSAR)

1.1.5.4.5 Coherence Evaluation

1.1.5.4.6 Low Resolution Interferometry

1.1.5.4.7 Conclusions

1.1.5.4.8 References

1.1.5.5 Wave Spectra

1.1.5.6 Simultaneous Observations

1.1.6 Summary of Applications vs Products

1.1.6.1 Summary of Applications Introduction

1.1.6.1.1 Remote Sensing Science

1.1.6.1.2 Earth Science

1.1.6.1.3 Commercial Applications

1.1.6.2 Ocean Applications

1.1.6.2.1 Wave Characteristics

1.1.6.2.2 Ocean Fronts

1.1.6.2.3 Coastal Dynamics

1.1.6.2.4 Oil Slicks and ShipTraffic

1.1.6.3 Land Applications

1.1.6.3.1 Global Vegetation Monitoring

1.1.6.3.2 Forestry

1.1.6.3.3 Geology and Topography

1.1.6.3.4 Agriculture

1.1.6.3.5 Natural Hazards

1.1.6.3.6 Flooding, Hydrology and Water Management

1.1.6.3.7 Urban Studies

1.1.6.3.8 References

1.1.6.4 Sea Ice Applications

1.1.6.4.1 Sea Ice Applications - Ice Sheet Dynamics

1.1.6.4.2 Sea Ice Applications - Snow Cover

1.1.6.4.3 Sea Ice Applications - Sea Ice Mapping

1.1.6.4.4 Sea Ice Application - Ship Routing through Sea Ice

1.2 How to Use ASAR Data

1.2.1 Software Tools

1.2.1.1 General Software Tools

1.2.1.2 EnviView

1.2.1.3 ASAR Toolbox

1.3 Further Reading

1.4 Image Gallery

2 ASAR Products and Algorithms

2.1 Products and Algorithms Introduction

2.1.1 Child Products

2.1.1.1 Definition

2.1.1.2 Child Product Extraction Requirements

2.1.1.2.1 Data Set Selection

2.1.1.2.2 ISP Subsets Selection (Extracted Instrument Headers)

2.1.1.2.3 Common Archiving Facility Requirements

2.2 Organisation of Products

2.3 Definitions and Conventions

2.3.1 Definitions

2.3.1.1 Global and Regional Coverage

2.3.1.2 Auxiliary Data

2.3.1.3 Geolocation and Geocoding

2.3.1.4 Product Confidence Data

2.3.1.5 Calibration

2.3.1.6 Processed Product Sizes and Coverage

2.3.2 Conventions

2.3.2.1 ENVISAT: General product structure

2.3.2.2 Main Product Header (MPH)

2.3.2.3 Specific Product Header (SPH)

2.3.2.4 Data Set Descriptors (DSD)

2.3.2.5 Data Set (DS)

2.4 Product Evolution History

2.5 ASAR Level 0 Products

2.5.1 Introduction

2.5.1.1 ASAR Instrument Source Packet

2.5.1.2 Level 0 Products

2.5.1.2.1 Processing Performed

2.5.1.2.2 High Data Rate Level 0 Products

2.5.1.2.2.1 Image Mode (ASA_IM_0P)

2.5.1.2.2.2 Alternating Polarisation (AP) Mode

2.5.1.2.2.3 Wide Swath (WS) Mode (ASA_WS_0P)

2.5.1.2.2.4 Level 0 External Characterisation (ASA_EC_0P)

2.5.1.2.3 Low Data Rate Level 0 Products

2.5.1.2.3.1 Global Monitoring (GM) Mode (ASA_GM_0P)

2.5.1.2.3.2 Wave Mode (WV) Level 0 Product (ASA_WV_0P)

2.5.1.2.3.3 Level 0 Module Stepping Mode (ASA_MS_0P)

2.5.1.3 Level 0 Formats

2.5.2 Level 0 Instrument Source Packet Description

2.6 Level 1B Products

2.6.1 ASAR Level 1B Algorithms

2.6.1.1 ASAR Level 1B Algorithm Physical Justification

2.6.1.1.1 Introduction

2.6.1.1.2 Radar Geometry

2.6.1.1.3 Pulse Compression

2.6.1.1.4 SAR Signal

2.6.1.1.5 Continuous versus Burst Data

2.6.1.1.6 Image Cross Spectra

2.6.1.2 ASAR Level 1B Algorithm Descriptions

2.6.1.2.1 Preprocessing

2.6.1.2.2 Doppler Frequency Estimator

2.6.1.2.2.1 Introduction

2.6.1.2.2.2 Madsen's Method

2.6.1.2.2.3 Multi-Look Cross Correlation (MLCC) Method

2.6.1.2.2.4 Look Power Balancing

2.6.1.2.2.5 PRF Diversity Method

2.6.1.2.2.6 Notes

2.6.1.2.2.7 References

2.6.1.2.3 Range-Doppler

2.6.1.2.3.1 Introduction

2.6.1.2.3.1.1 Overview

2.6.1.2.3.1.2 Range Compression

2.6.1.2.3.1.3 Azimuth FFT

2.6.1.2.3.1.4 Range Cell Migration Correction (RCMC)

2.6.1.2.3.1.5 Azimuth Compression

2.6.1.2.3.1.6 Summary

2.6.1.2.3.1.7 References

2.6.1.2.3.2 Processing Algorithms For AP SLC

2.6.1.2.3.2.1 Introduction

2.6.1.2.3.2.2 Background

2.6.1.2.3.2.3 Burst Mode Interferometry

2.6.1.2.3.2.4 Modifications To Range Doppler Algorithm

2.6.1.2.3.2.5 Conclusions

2.6.1.2.3.2.6 References

2.6.1.2.4 SPECAN

2.6.1.2.4.1 Introduction

2.6.1.2.4.1.1 Overview

2.6.1.2.4.1.2 Range Compression

2.6.1.2.4.1.3 Linear Range Cell Migration Correction (RCMC)

2.6.1.2.4.1.4 Azimuth Processing

2.6.1.2.4.1.5 Look Summation and Resampling

2.6.1.2.4.1.6 Product Processing

2.6.1.2.4.1.7 Summary

2.6.1.2.4.1.8 References

2.6.1.2.4.2 Descalloping

2.6.1.2.4.2.1 Scalloping

2.6.1.2.4.2.2 Methods for Scalloping Correction

2.6.1.2.4.2.2.1 Azimuth Descalloping Function Application

2.6.1.2.4.2.2.2 Doppler Centroid Frequency Estimation in the context of Burst Mode Data

2.6.1.2.4.2.3 Notes

2.6.1.2.4.2.4 References

2.6.1.2.4.3 ScanSAR Beam Merging

2.6.1.2.4.3.1 Determine a reference point in the blend region

2.6.1.2.4.3.2 Determine the limits of the blend region

2.6.1.2.4.3.3 Merge the data in the two beams corresponding to the blend region according to a predefined rule

2.6.1.2.4.4 Global Monitoring Mode Inverse Filter

2.6.1.2.5 ASAR Strip Line Product Processing

2.6.1.2.5.1 2.6.1.2.5.1 Introduction

2.6.1.2.5.1.1 Slice Size and Overlap

2.6.1.2.5.2 Processing Parameters Affected By Strip Line Product Continuity Requirements

2.6.1.2.5.2.1 I And Q Channel Statistics

2.6.1.2.5.2.2 Chirp Replica

2.6.1.2.5.2.3 Antenna Elevation Gain Correction

2.6.1.2.5.2.4 Doppler Centroid Estimation

2.6.1.2.5.2.5 along-track Pixel Spacing/Start Position

2.6.1.2.5.2.6 Slant Range/Ground Range (SR/GR) Conversion To Output Grid

2.6.1.2.5.2.7 FM Rate

2.6.1.2.5.2.8 First Output Range Sample

2.6.1.3 Level 1B Accuracies

2.6.2 Level 1B Products

2.6.2.1 Level 1B High Level Organisation of Products

2.6.2.1.1 Level 1B Image Products

2.6.2.1.1.1 Image Product Structure

2.6.2.1.1.1.1 Image Product Data Sets

2.6.2.1.1.2 Stand-Alone (On-Request) Image Products

2.6.2.1.1.2.1 Stand-Alone Product Types

2.6.2.1.1.2.1.1 Image Mode Single-Look Complex

2.6.2.1.1.2.1.2 Image Mode Precision Image

2.6.2.1.1.2.1.3 Image Mode Ellipsoid Geocoded Image

2.6.2.1.1.2.1.4 Alternating Polarisation Mode Single-Look Complex

2.6.2.1.1.2.1.5 Alternating Polarisation Mode Precision Image

2.6.2.1.1.2.1.6 Alternating Polarisation Ellipsoid Geocoded Image

2.6.2.1.1.2.2 Input Data

2.6.2.1.1.2.3 Auxiliary Data Used

2.6.2.1.1.3 Stripline Processed Image Products

2.6.2.1.1.3.1 Stripline Product Types

2.6.2.1.1.3.1.1 Image Mode Medium-resolution Image

2.6.2.1.1.3.1.2 Alternating Polarisation Medium-resolution Image

2.6.2.1.1.3.1.3 Wide Swath Medium-resolution Image

2.6.2.1.1.3.1.4 Global Monitoring Mode Image Product

2.6.2.1.1.3.2 Input Data

2.6.2.1.1.3.3 Auxiliary Data Used

2.6.2.1.1.3.4 Product Structure

2.6.2.1.2 Level 1B Wave Products

2.6.2.1.2.1 Product Types

2.6.2.1.2.1.1 Wave Mode SLC Imagette and Imagette Cross-Spectra

2.6.2.1.2.1.2 Wave Mode Imagette Cross-Spectra

2.6.2.1.2.2 Input Data

2.6.2.1.2.3 Auxiliary Data Used

2.6.2.1.2.4 Processing Performed

2.6.2.1.2.4.1 Wave Mode Error Handling

2.6.2.1.2.5 Product Structure

2.6.2.1.2.5.1 Main Product Header

2.6.2.1.2.5.2 Specific Product Header

2.6.2.1.2.5.3 Data Set Names

2.6.2.1.2.5.4 Data Sets

2.6.2.1.2.5.4.1 MDS Containing Imagettes

2.6.2.1.3 Browse Products

2.6.2.1.3.1 Product Types

2.6.2.1.3.1.1 Image Mode Browse Image

2.6.2.1.3.1.2 Alternating Polarisation Browse Image

2.6.2.1.3.1.3 Wide Swath Browse Image

2.6.2.1.3.1.4 Global Monitoring Mode Browse Image

2.6.2.1.3.2 Processing Performed

2.6.2.1.3.3 Product Structure

2.6.2.1.3.3.1 Browse SQ ADS

2.6.2.1.3.3.2 Subsampled Geolocation Grid ADS

2.6.2.2 Level 1B Engineering Quantities

2.6.2.2.1 Image Products

2.6.2.2.1.1 Medium Resolution Products

2.6.2.2.1.1.1 Image Mode Medium-resolution Image (ASA_IMM_1P)

2.6.2.2.1.1.2 Alternating Polarisation Medium-resolution Image (ASA_APM_1P)

2.6.2.2.1.1.3 Wide Swath Medium-resolution Image (ASA_WSM_1P)

2.6.2.2.1.2 Single-Look Complex (SLC) Products

2.6.2.2.1.2.1 Image Mode Single-Look Complex (ASA_IMS_1P)

2.6.2.2.1.2.2 Alternating Polarisation Mode Single-Look Complex (ASA_APS_1P)

2.6.2.2.1.3 Precision Image Products

2.6.2.2.1.3.1 Image Mode Precision Image (ASA_IMP_1P)

2.6.2.2.1.3.2 Alternating Polarisation Mode Precision Image (ASA_APP_1P)

2.6.2.2.1.4 Ellipsoid Geocoded Products

2.6.2.2.1.4.1 Image Mode Ellipsoid Geocoded Image (ASA_IMG_1P)

2.6.2.2.1.4.2 Alternating Polarisation Ellipsoid Geocoded Image (ASA_APG_1P)

2.6.2.2.1.5 Global Monitoring Products

2.6.2.2.1.5.1 Global Monitoring Mode Image Product (ASA_GM1_1P)

2.6.2.2.2 Wave Products

2.6.2.2.2.1 Imagette Cross-Spectra Products

2.6.2.2.2.1.1 Wave Mode SLC Imagette and Imagette Cross-Spectra (ASA_WVI_1P)

2.6.2.2.2.2 Single-Look Complex (SLC) Imagette Products

2.6.2.2.2.2.1 Wave Mode Imagette Cross-Spectra (ASA_WVS_1P)

2.6.2.3 Level 1B Essential Product Confidence Data

2.7 Level 2 Product and Algorithms

2.7.1 ASAR Level 2 Algorithms

2.7.1.1 General Description

2.7.1.2 Processing Steps

2.7.2 Level 2 Product

2.8 Instrument-specific Topics

2.9 Auxiliary Products

2.9.1 Summary of Auxiliary Data Sets

2.9.1.1 Auxiliary Data Files

2.9.1.2 Naming Strategy

2.9.1.3 Auxiliary Data Structure

2.9.1.4 Auxiliary Data MPH

2.9.1.5 Auxiliary Data SPH Structure

2.9.1.6 Auxiliary Data Sets

2.9.2 Auxiliary Data Sets for Level 1B Processing

2.9.3 Common Auxiliary Data Sets

2.9.3.1 FOS Orbit State Vectors

2.9.3.2 DORIS Preliminary Orbit State Vectors

2.9.3.3 DORIS Precise Orbit State Vectors

2.9.3.4 DORIS Navigator Level 0

2.9.3.5 UTC/SBT Time Conversion File

2.9.3.6 ECMWF Data Files

2.10 ASAR Latency Throughput and Data Volume

2.10.2 Throughput

2.10.2.1 Product parameters

2.10.3 Data Volume

2.10.3.1 Product Sizes for Disk Storage

2.11 ASAR Characterisation and Calibration

2.11.1 Introduction

2.11.2 Pre-flight Characterisation Measurements

2.11.3 Internal Calibration

2.11.3.1 Elevation Gain Monitoring

2.11.3.2 Chirp Replica Construction

2.11.3.3 PF-ASAR Normalisation

2.11.3.4 Module Stepping

2.11.4 External Characterisation

2.11.4.1 Characterisation of the Antenna Beam Pattern

2.11.4.2 Gain Calibration

2.11.4.3 Global Monitoring Mode

2.11.5 The Derivation of Backscattering Coefficients and RCSs in ASAR Products

2.11.7 References

2.12 ASAR Data Handling Cookbook

2.12.1 Hints and Algorithms for Data Use

2.12.1.1 Extracting Grid Information To Do Plots

2.12.1.2 Locating the Error Information

2.12.1.3 Converting Units of Engineering/Geophysical parameters

2.12.1.4 Displaying 'Scientific' PCD Information

2.12.2 Hints and Algorithms for Higher Level Processing

3 The ASAR Instrument

3.1 Instrument Description

3.1.1 Payload Description and Position on the Platform

3.1.1.1 ASA Subsystem

3.1.1.2 CESA Subsystem

3.1.1.2.1 Data Subsystem

3.1.1.2.2 Radio Frequency (RF) Subsystem

3.1.1.2.3 Control Subsystem (CSS)

3.1.1.2.4 Power Conditioning Unit (PCU)

3.1.2 ASAR Instrument Functionality

3.1.2.1 Global Mission

3.1.2.2 Regional Mission

3.1.3 Internal Data Flow

3.2 Instrument Characteristics and Performance

3.2.1 Preflight Characteristics and Expected Performance

3.2.2 Inflight Performance Verification

4 ASAR Frequently Asked Questions

5 ASAR Glossary Terms

5.1 Acronyms and Abbreviations

5.2 RADAR and SAR Glossary

5.3 Product Terms

5.4 ASAR Instrument Glossary

5.5 Geometry Glossary

5.6 Oceans Glossary

5.7 Land Glossary

5.8 Sea Ice Glossary

6 ASAR Data Formats Products

6.1 Level 2 Products

6.1.1 ASA_WVW_2P: ASAR Wave Mode Wave Spectra

6.2 Level 1 Products

6.2.1 ASA_APG_1P: ASAR Alternating Polarization Ellipsoid Geocoded Image

6.2.2 ASA_APM_1P: ASAR Alternating Polarization Medium Resolution Image product

6.2.3 ASA_APP_1P: ASAR Alternating Polarization Mode Precision Image

6.2.4 ASA_APS_1P: ASAR Alternating Polarization Mode Single Look Complex

6.2.5 ASA_GM1_1P: ASAR Global Monitoring Mode Image

6.2.6 ASA_IMG_1P: ASAR Image Mode Ellipsoid Geocoded Image

6.2.7 ASA_IMM_1P: ASAR Image Mode Medium Resolution Image

6.2.8 ASA_IMP_1P: ASAR Image Mode Precision Image

6.2.9 ASA_IMS_1P: ASAR Image Mode Single Look Complex

6.2.10 ASA_WSM_1P: ASAR Wide Swath Medium Resolution Image

6.2.11 ASA_WVI_1P: ASAR Wave Mode SLC Imagette and Imagette Cross Spectra

6.2.12 ASA_WVS_1P: ASAR Wave Mode Imagette Cross Spectra

6.2.13 ASA_WSS_1P: Wide Swath Mode SLC Image

6.3 Level 0 Products

6.3.1 ASA_APC_0P: ASAR Alternating Polarization Level 0 (Copolar)

6.3.2 ASA_APH_0P: ASAR Alternating Polarization Level 0 (Cross polar H)

6.3.3 ASA_APV_0P: ASAR Alternating Polarization Level 0 (Cross polar V)

6.3.4 ASA_EC__0P: ASAR Level 0 External Characterization

6.3.5 ASA_GM__0P: ASAR Global Monitoring Mode Level 0

6.3.6 ASA_IM__0P: ASAR Image Mode Level 0

6.3.7 ASA_MS__0P: ASAR Level 0 Module Stepping Mode

6.3.8 ASA_WS__0P: ASAR Wide Swath Mode Level 0

6.3.9 ASA_WV__0P: ASAR Wave Mode Level 0

6.4 Browse Products

6.4.1 ASA_AP__BP: ASAR Alternating Polarization Browse Image

6.4.2 ASA_GM__BP: ASAR Global Monitoring Mode Browse Image

6.4.3 ASA_IM__BP: ASAR Image Mode Browse Image

6.4.4 ASA_WS__BP: ASAR Wide Swath Browse Image

6.5 Auxilliary Products

6.5.1 ASA_CON_AX: ASAR Processor Configuration

6.5.2 ASA_INS_AX: ASAR Instrument characterization

6.5.3 ASA_XCA_AX: ASAR External calibration data

6.5.4 ASA_XCH_AX: ASAR External characterization data

6.6.1 Main Product Header

6.6.2 ASAR processor configuration data

6.6.3 ASAR instrument characterization data

6.6.4 ASAR external calibration data

6.6.5 ASAR external characterization data

6.6.6 Antenna Elevation pattern

6.6.7 Chirp parameters

6.6.8 Doppler Centroid parameters

6.6.9 Geolocation Grid ADSRs

6.6.10 Measurement Data Set 1

6.6.11 ASAR Image Products SPH

6.6.12 Main Processing parameters

6.6.13 Map Projection parameters

6.6.14 Ocean Wave Spectra

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

6.6.16 SQ ADSRs

6.6.17 Slant Range to Ground Range conversion parameters

6.6.18 ASAR Wave Mode Products Base SPH

6.6.19 Wave Mode Geolocation ADS

6.6.20 Wave Mode processing parameters

6.6.21 SQ ADSRs

6.6.22 ASAR WVI Product SPH

6.6.23 SPH for auxiliary data with N=1 DSDs

6.6.24 Level 0 MDSR

6.6.25 Level 0 SPH

6.6.26 Doppler Centroid parameters

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry

Copyright 2000 - European Space Agency. All rights reserved.