Calibration and validation of satellite sensors SharleneAsia Naicker

Calibration and validation of satellite sensors Sharlene-Asia Naicker Maanda Rambau Sedzani Elia Muravha Amanda Forbes Busisiwe Nkuzani 1

Overview § § § § § Introduction Definition and importance Technology trends Challenges Best practices Career scope Conclusion Questions Bibliography 2

Definition § Calibration: • Validation of specific techniques and measurements of equipment. • Comparison of measurements with a known standard or other devices. • Scientifically assessing a systems response to known controlled signal inputs. • Responses that are traceable to Cal/Val standards. 3

Definition § Validation: • Product and process that conforms to the necessary user requirements and specifications. • Process of assessing the quality data that is derived a systems output. 4

Importance § § § Building blocks of all satellites programs. Data from different sensors are processed. Reliability and possibility of uncertainties are established. Needed for airborne, space borne, images and data retrieval. Can be done in a shuttle or on a satellite. Instruments performance and calibration accuracy. 5

Importance § Needed to be done: Pre-launch: data to be accurate and reliable. • In-orbit: High temporal resolution and prior data acquisition. • Post-launch: Using in-situ measurements and provide reference data for future calibration and validation measurements. • 6

Importance § § § Generate consistent and accurate data. To determine progress of validation. One kind of calibration is enough. Techniques such as relative and absolute which use uniform spatial radiance are efficient. Technically demanding but require international standards. Data quality, competency and aid detection methods. 7

Importance § § § Both provide consistency, reliability, quality and availability. Biological, geological, environmental sciences. Habitat change, biodiversity, vegetation, mapping are significant. Confidence in data that is well calibrated and validated and provide traceability Inter-comparison and long term studies and product specifications are achieved. 8

The challenges facing calibration and validation General Challenges § Lack of funding § Technical challenges § Lack of resources § Lack of regular comparison of instrumentation and methodologies. § Lack of endorsement and support. § Lack of framework development, guideline standards, best practices and recommendations. 9

The challenges facing calibration and validation Calibration challenges: § Pre-launch calibration: • Reproducing the essential features of the space environment. • Vibration, extreme temperatures and contamination. • Changes in time. • Radiometric produces uncertainty and cost and spatial invariance or broad land coverage. 10

The challenges facing calibration and validation Calibration challenges: § On board calibration • The full field view of the sensor is not available. • The accuracy is not as high as pre-launch calibration. § Vicarious calibration • The target might not be homogenous or easily accessible. • The size and complexity of the mission is increased. 11

The challenges facing calibration and validation Calibration challenges: § Post-launch calibration • Platform may be damaged or degraded in time. • Uncertainty in reliability by neglecting a measurement. • Atmospheric characteristics. • Human errors. 12

The technology trends in calibration and validation § Three things that need to be done to improve the technology for the calibration and validation process: Instrument Calibration • Instrument Validation • Instrument Re-qualifications • 13

The technology trends in calibration and validation § Instruments • Integrating Sphere 14

The technology trends in calibration and validation § Inexpensive Near-IR Sunphotometer 15

Best Practices CEOS § WGCV § Quality Assurance Framework for Earth Observation (QA 4 EO) § 16

QA 4 EO § 7 Guidelines on Data Quality 17

QA 4 EO § 2 Guidelines on Data Policy • Guidelines on how to document the data and how to exchange the data § DPK 001 : Procedures and Policies • DPK 002: Metadata Requirements 18

QA 4 EO § 1 Guideline on Communication and Education l CEK 001 • • • Peer review Common Terminology Cal/Val Portal 19

IVOS Chaired by Nigel Fox § Mission is to monitor the quality of data from Infrared and Visible Optical Earth Observation Satellites through the quality of calibration and validation and international collaboration § 20

Where to study for Cal. Val §University of Stellenbosch §University of Cape Town §University of Johannesburg §University of KZN §University of Limpopo §University of Fort Hare §University of Venda 21

§University of South Africa §University of Free state §Nelson Mandela Metropolitan §Rhode University §Wits University §University of Pretoria §North –West University 22

Career Scope §Studying Cal/Val can bring different career opportunities since it is a broad field that includes the following: • Geoinformation Specialist • Image processing researcher • GIS researcher • Space science facilitator 23

§Electronic technologist or engineer §Software engineer §Electronic engineer §Satellite system engineer §Control system engineer §Mechanical engineer §Electrical engineer §Remote sensing researcher 24

Conclusion Cal/Val is becoming the most important part of the remote sensing process. § More research and awareness campaigns are required. § 25

Thank you § § § § . n tio Ms M Lubbe n Mr L Vhengani e t t a ? Dr M Lysko r ? u s? o y Mr D Griffith n r o i t o f es Patricia Govender u o Qu y CSIR k ny n a A DST h T Everyone that has helped us. 26

Bibliography §Full bibliography is available in the final report submitted. 27