Modern mobile handsets do have powerful processors that allow for signal processing in combination with SDR boards. This application implements a proof-of-concept system capable of receiving, decoding and displaying satellite data.
This is an open-source project: https://gitlab.com/librespacefoundation/sdrmakerspace/sdr-mobile
Find detailed usage instructions on project wiki: https://gitlab.com/librespacefoundation/sdrmakerspace/sdr-mobile/-/wikis/Satellite-hunting-with-SDR-Mobile-HowTo-guide