This MIT Technology Review report provides the details of the work done by Professor Humphrey and his team to reverse engineer starlink signals: https://www.google.com/amp/s/www.technologyreview.com/2022/10/21/1062001/spacex-starlink-signals-reverse-engineered-gps/amp/

It is worth it to mention that Elon Musk does not like using starlink for navigation which is the motivation behind Humphrey

Although the report mentions Humphrey non-peer reviewed paper, actually the peer-reviewed paper has been published here

Hesham