What is GNU Radio
GNU Radio is an open-source toolkit for building software-defined radios (SDRs) and signal processing systems. It’s widely used by hobbyists, researchers, and professionals for real-time signal analysis, radio astronomy, satellite communications, and many other radio-frequency (RF) applications.
Key Features:
- Graphical interface (GNU Radio Companion – GRC): Allows you to build signal processing flowgraphs using drag-and-drop blocks, making complex systems easier to visualize.
- Python & C++ support: The underlying processing is in C++ for speed, while Python is used to glue the blocks together, making it flexible and easy to customize.
- Real-time signal processing: You can process data in real time, ideal for decoding radio signals, demodulating transmissions, or recording and analyzing RF data.
- Supports SDR hardware: Works with devices like RTL-SDR, HackRF, USRP (by Ettus), LimeSDR, and more.
- Extensible: Users can write custom blocks in C++ or Python for specialized processing.
Common Uses:
- Receiving and demodulating FM/AM/SSB signals.
- Building radio telescopes (e.g., processing 1420 MHz hydrogen line data).
- Analyzing satellite beacons and telemetry.
- Decoding ADS-B (aircraft), AIS (ships), or weather satellite transmissions.
- Educational purposes in DSP (Digital Signal Processing).
Example in Radio Astronomy:
You might use GNU Radio to:
- Capture data from an SDR connected to a simple dipole antenna.
- Filter and demodulate the signal around 1420 MHz.
- Record and analyze intensity or Doppler shift data for hydrogen line studies.