alos palsar cal/val activities
TRANSCRIPT
ALOS PALSAR Cal/Val Activities
prepared by
Peter Meadows, N. Miranda, B. Rosich
ESA ADEN-PALSAR QC and Cal/Val activities
- Since mid 2007 ESA put in place Quality Control service (ALOS-DPQC):
- Routine QC analysis
- Instrument anomaly detection
- PALSAR performance and calibration monitoring
- Activity supported by a set of analysis tools:
- CALIX for basic and advance polarimetric analysis
- SARCON for product verification, IRF, calibration and APmonitoring- PALSAR verification processor:
- Prototype processor for full qualityassessment :
- Polarimetry
- Polarimetric calibration
- Interferometry
ALOS DPQC : PALSAR routine QC activity
- Routine Analysis
- Systematic QC of PALSAR L1.0, L1.1
& L1.5 ADEN products (Europe &
Africa)
- Visual Inspection of a subset of L1.1 &
L1.5 products
- image quality artefacts (e.g. azimuth
and range ambiguities, interference)
- Help Desk Support (1-2 day delay)
- Weekly QC reports
- Visual anomaly reports (2weeks)
- Product quality disclaimerALOS DPQC
ALOS ADEN DATA
Issues and
recommendations
submitted to JAXA
ALOS DPQC : Long Term monitoring
- ADEN PALSAR Cal/Val plan definition
- Identification of calibration sites
- Absolute calibration
- no PALSAR CR/transponders
available (in ADEN zone)
!ground stations (NE, Tromso, MS,
and MA) being assessed as a
potential calibration sites (used for
ERS & ASAR)
-Antenna Pattern monitoring
- ADEN don’t cover Amazonian RF
!African tropical rain forest (L-band
rain forest less homogeneous than
at C-band)
African RF
Maspalomas ESA/NASA GS
ALOS DPQC : Long Term monitoring
- Detailed quality assessment
- Doppler frequency monitoring
- Point (IRF) and distributed targetanalysis
- NES0 measurements
- Elevation antenna patternmonitoring
- localisation accuracy, ambiguityanalysis
- Polarisation calibration andFaraday rotation analysis
- Report available to users
http://earth.esrin.esa.it/pcs/alos/palsar/reports/cyclic/
- Generated 10 days after the end ofthe cycle (46 days)
ALOS ADEN DATACyclic report
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0 500 1000 1500 2000 2500 3000
Frame
Att
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Pitch
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DPQC Web
ALOS DPQC
- Long term analysis shows several product anomalies
- Instrument performance and product characteristics are within
the requirement
ALOS DPQC : PALSAR performance
PALSAR product current issues:
- For Level 1.1 products:
- near, mid and far swath incidenceangles are not consistent witheach other
- corner lat/long values and platformheading not annotated
- High ambiguity level (azimuth andrange).
- For Scansar products:
- the processed azimuth bandwidthis incorrectly set to 0
- Quality issues : Visible sub-swathboundaries, scalloping, ADCsaturation effects, high ambiguitylevel (azimuth and range).
- For fine mode and polarimetric mode,radiometric error at far range is visible
- Image artefacts found in L1.5 productswhen using the bi-linear and cubicconvolution interpolation methods
- Interference effects have been identified inseveral PALSAR images
Issue and recommendation submitted to JAXA
PALSAR Verification Processor
- Development of a PALSAR prototype
interferometric processor
- Fine mode and WS phase-preserving processor
(focusing at zero-doppler)
- Interference removal
- Atmosphere modelling
- Polarimetric calibration and analysis
- InSAR /D-InSAR interferometry
- geocoding
à Flexible set of tools for assessing PALSAR
capacities
Presentation of results and application on Day 4, morning
session:
Interferometry and new SAR missions
PALSAR interferogram:
(05/06/2006-20/02/2007)
Le piton de la Fournaise
ADEN PALSAR what is next…
ESA wants to promote L-band data usage in Europe
- L-band (polarimetric) data is useful for manyapplications:
- forest and agricultural monitoring (polarimetric capacity)
- InSAR/D-InSAR (fast movement and good coherencepreservation)
- The verification processor & QC activities show thatthere is room for quality improvement
- Development of ESA operational processors
- JERS (apr-jun 2008):
- CEOS & Envisat format
- ESA PALSAR processor:
!inherit from the verification processor project
- Zero-Doppler geometry
- CEOS (& Envisat format ?)
- Room for recommendations
ASAR HH 22 ASAR HH 22 MayMay –– 12 12 JulyJuly –– 16 16 AugustAugust 2006 2006
PALSAR HH 19 PALSAR HH 19 MayMay –– 4 4 JulyJuly –– 19 19 AugustAugust 2006 2006
- Identification of Calibration Sites
- Within Europe & Africa we are notaware of transponders or cornerreflectors currently being usingfor PALSAR quality assessmentand radiometric calibration
- For ERS SAR and Envisat ASAR,ground stations have beensuccessfully used as secondarycalibration sources
- Imagery of ground stations atNeustrelitz, Tromso, Maspalomas,and Matera being assessed as apotential calibration sites
- For antenna pattern assessmentlarge distributed uniform targetssuch as the Amazon rainforesthave traditionally been used.Within Europe & Africa it mightbe possible to use the Africantropical rain forest. However L-band rain forest data exhibitsmuch more variability than at C-band.
- Cyclic Reports
- Detailed summary of qualityassessment and calibrationactivities such as
- Doppler centroid frequencymonitoring,
- point target IRF analysis,
- distributed target analysis,
- noise equivalent sigma zeromeasurements,
- elevation antenna patternmonitoring,
- localisation accuracy,
- ambiguity analysis,
- dual and quad polarisationcalibration and
- Faraday rotation analysis.
- Report to be made available tousers
- Generated 10 days after theend of each ALOS 46 dayrepeat cycle
- In fine mode and polarimetric mode, the radiometric error at far range
is still visible for ADEN data
- Image artefacts found in L1.5 products when using the bi-linear and
cubic convolution interpolation methods
- Interference effects have been identified in several PALSAR images
- Issues with InSAR co-registration of L1.1 products with different
Doppler centroid frequencies (as the L1.1 products are not in zero-
Doppler coordinates).