Issue 14 of general aviation EASA publication Sunny Swift, available in 20 languages, talks about the benefits of certified ELTs that are registered and encoded with GNSS positions.
Document EASA SIB 2019-09 has also been published on ELT and PLB annual testing.
EASA provides links in Issue 14 to information about the Cospas-Sarsat System, ELT installation and maintenance, operational rules, and more.
Read more here:
https://www.easa.europa.eu/newsroom-and-events/news/sunny-swift-emergency-locator-transmitters#group-easa-downloads