Data from Earth observation satellites increasingly underpins reporting, assessment and decision-making by governments and important global issues such as sustainable development goals, including climate change and land degradation. End-users need to be confident that the provenance and quality of this data is reliable and accurate.
It is also vital that data from different satellites, or data collected between dates by the same satellite, can be seamlessly used and accurately compared, in order to make effective use of Earth observation data, maintain the scientific value of data archives, and meet stringent regulatory or legal constraints.
Satellite calibration and validation is similar to quality control on a production line. Calibrating sensors ensures the data they capture is aligned with physical standards. The process of validation checks that information derived from satellite sensors is comparable to ground measurements, and verifies that the space-derived measurements are a true representation of what is happening on the ground.
Sensors and ground stations
Over four decades we have developed unique expertise in the application of Earth observation data as well the development of sensors and infrastructure used to calibrate sensors and validate data products.
We operate satellite calibration and validation infrastructure in Australia, and conduct dedicated field campaigns to help calibrate several satellites. This breadth and depth of knowledge is highly valued by our international partners and future Australian Earth observation data providers.
Lucinda Jetty Coastal Observatory is a ground-based observatory, located at the end of Lucinda Jetty, nearly 6km off the coast near the mouth of the Herbert River. This places it at the border of the wet and dry tropical regions off the northeast coast of Australia. Capturing both atmospheric and marine data, the observatory is used to validate optical satellite observations. Established in collaboration with the Integrated Marine Observing System (IMOS), it is the only permanent ground truthing station for the Sentinel missions in the Southern Hemisphere.
Another calibration site in Tumbarumba, NSW, supports multiple applications of satellite data uses, including estimation of aerosols, forest structure measurements from spaceborne lidar, land surface temperature and vegetation fluorescence.
We are developing an autonomous calibration site at the Pinnacles Desert approximately 200km from Perth in Western Australia. Designed to support future spaceborne imaging spectroscopy sensors, it is also expected to contribute to other multispectral optical sensors such as Landsat 8 and Sentinel2. Instruments on the site will aim to acquire continuous radiometric data and associated meteorological and atmospheric composition data contributing to international vicarious calibration efforts.
Also in development is an inland water observatory at Googong Dam, south of Canberra. The observatory will provide water quality validation data for satellite-derived water quality products. The site is expected to be operational early 2023.
In addition to these permanent ground stations, we are collaborating on satellite cross-calibration projects, including the USGS Satellite Cross-Calibration Radiometer (SCR) mission.