Decode signals from weather satellites

Weather satellites transmit signals that you can receive and decode to generate images of the Earth. Mike Bedford shows you how.

- Mike Bedford

Satellite-based images of the Earth showing cloud cover have been a regular sight in TV weather broadcasts since the TIROS 1 satellite launched in 1960. Yet while the end result is familiar, the technology that brings us those images is much less well-appreciated. If you want to learn about the technology involved, though, it’s not too difficult to get a basic understanding.

However, you can gain some hands-on experience, as we demonstrate here, and a practical approach is often one of the best ways of learning. So, we’ll show you how to receive the radio signals transmitted by these satellites and how to decode that data to generate pictures. In addition, we’ll also investigate some ways of image processing to improve that image and perhaps introduce some false colour into the inherently monochrome images transmitted by the satellites.

NOAA satellites

Here we’re going to be looking at the so-called NOAA polar orbiting satellites – NOAA-15, NOAA-18 and NOAA19 – that are operated by America’s National Oceanic and Atmospheric Administration. We’ve chosen these satellites because they orbit the Earth at an altitude of just 850km. Since they aren’t too far above our heads, their radio signals are quite strong and easy to receive.