Earth observation satellites provide us with images from around the globe and can help us monitor and see areas far too remote for human access. This makes EO perhaps the most easily recognisable satellite application: it is used to help provide weather forecasts and create maps. Potential uses for EO include, but are not limited to, frequent urban change detection for planning enforcement; highlighting in real time where local air quality could trigger health issues to allow residents and health care providers to take precautionary measures; and measuring and mapping the extent of land subsidence and visualisation of policies such as urban green space planning and management.
There are two main types of EO satellite: optical and radar. The key difference between these two types is that optical satellites are passive detectors and radar satellites are active.
Optical satellites use reflected sunlight to gather data. This means the images they create are what you would expect to see with the naked eye: if it is cloudy beneath the satellite you will get a picture of clouds. Radar satellites emit microwave pulses which reflect off ground features. One of the many advantages of radar imagery is that it can detect ground features through cloud, 24 hours a day.
The data received from both types can be processed in numerous ways to provide a variety of products and services. This enables us to get a complete picture of what is happening on our Earth, from the slow spread of air pollution across a continent to the exact damage in any specific region from a natural disaster.
The European Commission is coordinating and managing a ground-breaking Earth observation programme called Copernicus. This programme offers a wide range of EO services, free at the point of use.
Much of the data for the Copernicus services will come from a constellation of Earth observation satellites called Sentinels. The data these Sentinels will send back to Earth is free to access and will be used to provide information on emergency/disaster monitoring, land monitoring, sea monitoring and atmospheric composition.
With so many satellite data sources available from public and private satellite operators, the Satellite Applications Catapult in association with the UK Space Agency has funded and built a mechanism for end users to discover what is available and how to get it.
The Data Discovery Hub is an aggregation of links to the suppliers of satellite data through a single interface and where possible making the raw data and satellite derived data available for exploration and download.
The Sentinel Data Access Service (SEDAS) is a joint data access portal developed by the UK Space Agency in collaboration with the Satellite Applications Catapult that allows the UK community to access 30 days of high-quality satellite data through the Copernicus Programme and the Sentinels. If you have any questions about downloading data from SEDAS, please contact the team on 01235 567 999.