The SIG-UAS is relatively young and until now two workshops have been organized both in Warsaw in Poland. More details on the content and program for these workshops you can find in the links below:
First EARSeL UAS Workshop, September 05-07, 2018: http://uas.earsel.org/workshop/1st-uas-ws/
Second EARSeL UAS Workshop, 7-10 June, 2021: http://symposium.earsel.org/40th-symposium-Warszaw/uas-workshop/
We are currently making preparations for the third EARSeL UAS Workshop. Announcements will be made in the first months of 2022.