Calibration and validation of satellite sensors

Calibration and validation of Calibration and validation of satellite sensorssatellite sensors

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Sharlene-Asia NaickerSharlene-Asia Naicker

Maanda RambauMaanda Rambau

Sedzani Elia MuravhaSedzani Elia Muravha

Amanda ForbesAmanda Forbes

Busisiwe NkuzaniBusisiwe Nkuzani

OverviewOverview

IntroductionIntroduction Definition and importance Definition and importance Technology trendsTechnology trends ChallengesChallenges Best practicesBest practices Career scopeCareer scope ConclusionConclusion QuestionsQuestions BibliographyBibliography

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DefinitionDefinition

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Calibration:Calibration:• Validation of specific techniques and Validation of specific techniques and

measurements of equipment.measurements of equipment.• Comparison of measurements with a known Comparison of measurements with a known

standard or other devices.standard or other devices.• Scientifically assessing a systems response to Scientifically assessing a systems response to

known controlled signal inputs.known controlled signal inputs.• Responses that are traceable to Cal/Val Responses that are traceable to Cal/Val

standards.standards.

DefinitionDefinition

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Validation:Validation:

• Product and process that conforms to the Product and process that conforms to the necessary user requirements and necessary user requirements and specifications.specifications.

• Process of assessing the quality data that is Process of assessing the quality data that is derived a systems output.derived a systems output.

ImportanceImportance

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Building blocks of all satellites programs.Building blocks of all satellites programs. Data from different sensors are processed.Data from different sensors are processed. Reliability and possibility of uncertainties are Reliability and possibility of uncertainties are

established.established. Needed for airborne, space borne, images and Needed for airborne, space borne, images and

data retrieval.data retrieval. Can be done in a shuttle or on a satellite.Can be done in a shuttle or on a satellite. Instruments performance and calibration Instruments performance and calibration

accuracy.accuracy.


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Needed to be done:Needed to be done:

• Pre-launch: data to be accurate and reliable.Pre-launch: data to be accurate and reliable.• In-orbit: High temporal resolution and prior In-orbit: High temporal resolution and prior

data acquisition.data acquisition.• Post-launch: Using in-situ measurements and Post-launch: Using in-situ measurements and

provide reference data for future calibration provide reference data for future calibration and validation measurements.and validation measurements.


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Generate consistent and accurate data.Generate consistent and accurate data. To determine progress of validation.To determine progress of validation. One kind of calibration is enough.One kind of calibration is enough. Techniques such as relative and absolute which Techniques such as relative and absolute which

use uniform spatial radiance are efficient.use uniform spatial radiance are efficient. Technically demanding but require international Technically demanding but require international

standards.standards. Data quality, competency and aid detection Data quality, competency and aid detection

methods.methods.


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Both provide consistency, reliability, quality and Both provide consistency, reliability, quality and availability.availability.

Biological, geological, environmental sciences.Biological, geological, environmental sciences. Habitat change, biodiversity, vegetation, Habitat change, biodiversity, vegetation,

mapping are significant.mapping are significant. Confidence in data that is well calibrated and Confidence in data that is well calibrated and

validated and provide traceabilityvalidated and provide traceability Inter-comparison and long term studies and Inter-comparison and long term studies and

product specifications are achieved.product specifications are achieved.

The challenges facing calibration and The challenges facing calibration and validationvalidation

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General ChallengesGeneral Challenges Lack of fundingLack of funding Technical challengesTechnical challenges Lack of resourcesLack of resources Lack of regular comparison of instrumentation and Lack of regular comparison of instrumentation and

methodologies.methodologies. Lack of endorsement and support.Lack of endorsement and support. Lack of framework development, guideline Lack of framework development, guideline

standards, best practices and recommendations.standards, best practices and recommendations.


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Calibration challenges: Calibration challenges:

Pre-launch calibration:Pre-launch calibration:• Reproducing the essential features of the space Reproducing the essential features of the space

environment.environment.• Vibration, extreme temperatures and Vibration, extreme temperatures and

contamination.contamination.• Changes in time.Changes in time.• Radiometric produces uncertainty and cost and Radiometric produces uncertainty and cost and

spatial invariance or broad land coverage.spatial invariance or broad land coverage.


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Calibration challenges: Calibration challenges: On board calibrationOn board calibration

• The full field view of the sensor is not available.The full field view of the sensor is not available.• The accuracy is not as high as pre-launch The accuracy is not as high as pre-launch

calibration.calibration. Vicarious calibrationVicarious calibration

• The target might not be homogenous or easily The target might not be homogenous or easily accessible.accessible.

• The size and complexity of the mission is The size and complexity of the mission is increased.increased.


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Calibration challenges: Calibration challenges:

Post-launch calibrationPost-launch calibration• Platform may be damaged or degraded in time.Platform may be damaged or degraded in time.• Uncertainty in reliability by neglecting a Uncertainty in reliability by neglecting a

measurement.measurement.• Atmospheric characteristics.Atmospheric characteristics.• Human errors.Human errors.

The technology trends in calibration The technology trends in calibration and validationand validation

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Three things that need to be done to improve the Three things that need to be done to improve the technology for the calibration and validation technology for the calibration and validation process:process:

• Instrument CalibrationInstrument Calibration• Instrument ValidationInstrument Validation• Instrument Re-qualificationsInstrument Re-qualifications


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InstrumentsInstruments• Integrating SphereIntegrating Sphere

Inexpensive Near-IR SunphotometerInexpensive Near-IR Sunphotometer


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CEOSCEOS WGCVWGCV Quality Assurance Framework for Earth Quality Assurance Framework for Earth

Observation (QA4EO)Observation (QA4EO)

Best PracticesBest Practices

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QA4EOQA4EO

7 Guidelines on Data Quality7 Guidelines on Data Quality

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QA4EOQA4EO

2 Guidelines on Data Policy2 Guidelines on Data Policy• Guidelines on how to document the data and Guidelines on how to document the data and

how to exchange the datahow to exchange the data

DPK001 : Procedures and PoliciesDPK001 : Procedures and Policies• DPK002: Metadata RequirementsDPK002: Metadata Requirements

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QA4EOQA4EO

1 Guideline on Communication and 1 Guideline on Communication and EducationEducation CEK001CEK001

• Peer reviewPeer review• Common TerminologyCommon Terminology• Cal/Val PortalCal/Val Portal

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IVOSIVOS

Chaired by Nigel FoxChaired by Nigel Fox Mission is to monitor the quality of data Mission is to monitor the quality of data

from Infrared and Visible Optical Earth from Infrared and Visible Optical Earth Observation Satellites through the quality Observation Satellites through the quality of calibration and validation and of calibration and validation and international collaborationinternational collaboration

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Where to study for CalValWhere to study for CalVal

University of StellenboschUniversity of StellenboschUniversity of Cape TownUniversity of Cape TownUniversity of JohannesburgUniversity of JohannesburgUniversity of KZNUniversity of KZNUniversity of LimpopoUniversity of LimpopoUniversity of Fort HareUniversity of Fort HareUniversity of Venda University of Venda

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University of South AfricaUniversity of South AfricaUniversity of Free stateUniversity of Free stateNelson Mandela MetropolitanNelson Mandela MetropolitanRhode UniversityRhode UniversityWits UniversityWits UniversityUniversity of PretoriaUniversity of PretoriaNorth –West UniversityNorth –West University

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Career ScopeCareer ScopeStudying Cal/Val can bring different Studying Cal/Val can bring different career opportunities since it is a broad career opportunities since it is a broad field that includes the following:field that includes the following:

•Geoinformation SpecialistGeoinformation Specialist•Image processing researcherImage processing researcher•GIS researcherGIS researcher•Space science facilitatorSpace science facilitator

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Electronic technologist or engineerElectronic technologist or engineerSoftware engineerSoftware engineerElectronic engineerElectronic engineerSatellite system engineerSatellite system engineerControl system engineerControl system engineerMechanical engineerMechanical engineerElectrical engineerElectrical engineerRemote sensing researcherRemote sensing researcher

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ConclusionConclusion

Cal/Val is becoming the most important Cal/Val is becoming the most important part of the remote sensing process.part of the remote sensing process.

More research and awareness campaigns More research and awareness campaigns are required. are required.

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Thank youThank you

Ms M LubbeMs M Lubbe Mr L VhenganiMr L Vhengani Dr M LyskoDr M Lysko Mr D GriffithMr D Griffith Patricia GovenderPatricia Govender CSIRCSIR DSTDST Everyone that has helped us.Everyone that has helped us.

Thank you fo

r your a

ttentio

n.

Any Questi

ons???

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Full bibliography is available in the final Full bibliography is available in the final report submitted.report submitted.

BibliographyBibliography

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Calibration and validation of satellite sensors

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