alos palsar cal/val activities

15
ALOS PALSAR Cal/Val Activities prepared by Peter Meadows, N. Miranda, B. Rosich

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Page 1: ALOS PALSAR Cal/Val Activities

ALOS PALSAR Cal/Val Activities

prepared by

Peter Meadows, N. Miranda, B. Rosich

Page 2: ALOS PALSAR Cal/Val Activities

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

Page 3: ALOS PALSAR Cal/Val Activities

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)

[email protected]

- Weekly QC reports

- Visual anomaly reports (2weeks)

- Product quality disclaimerALOS DPQC

ALOS ADEN DATA

Issues and

recommendations

submitted to JAXA

Page 4: ALOS PALSAR Cal/Val Activities

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

Page 5: ALOS PALSAR Cal/Val Activities

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

-4

-3

-2

-1

0

1

2

3

4

0 500 1000 1500 2000 2500 3000

Frame

Att

itu

de

(d

eg

)

Pitch

Roll

Yaw

DPQC Web

ALOS DPQC

Page 6: ALOS PALSAR Cal/Val Activities

- Long term analysis shows several product anomalies

- Instrument performance and product characteristics are within

the requirement

ALOS DPQC : PALSAR performance

Page 7: ALOS PALSAR Cal/Val Activities
Page 8: ALOS PALSAR Cal/Val Activities

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

Page 9: ALOS PALSAR Cal/Val Activities

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

Page 10: ALOS PALSAR Cal/Val Activities

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

Page 11: ALOS PALSAR Cal/Val Activities
Page 12: ALOS PALSAR Cal/Val Activities
Page 13: ALOS PALSAR Cal/Val Activities
Page 14: ALOS PALSAR Cal/Val Activities

- 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

Page 15: ALOS PALSAR Cal/Val Activities

- 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).