REP(MUS) (Robotic Experimentation and Prototyping using Maritime Uncrewed Systems) is an annual experimentation exercise for Unmanned Maritime Systems organized and hosted by the Portuguese Navy, NATO and Faculty of Engineering - University of Porto, co-organized by the European Defence Agency,[1] with the participation of forces from foreign military forces, universities and tech companies. The exercise has the objective of testing different types of unmanned aerial vehicles, unmanned surface vehicles, unmanned undersea vehicles, and unmanned ground vehicles. Today it is the largest UAV testing exercise, with the participation of several NATO countries.[2][3] In recent years it has been the largest exercise for experimenting with unmanned vehicles in the world.[4]