GNU Radio is used extensively in industry and academia. Hawkeye 360 and Spire use GNU Radio for satellite ground stations. Lockheed Martin, SpaceX, and a variety of other aerospace/defense use it as well for other wireless comms applications. DeepSig uses GNU Radio at least to generate test signals for their neural net based signal classification system and communication systems, possibly also internally. Analog Devices uses GNU Radio in their Scopy oscilloscope/spectrum analyzer/signal and logic analyzer application.

As said by the other commenter, check out the videos on our YouTube channel. The project is very fortunate to attract many interesting talks and speakers each year at the conference.

https://www.youtube.com/GNURadioProject https://www.gnuradio.org