FWIW--I think gps units aren't seen BY the satellites; rather, the gpsr sees the satellites and constantly calculates its location based on triangulation and its mapset. This is for handhelds (Oregon, eTrex) and automotives (Nuvi); admittedly I don't know anything about the ones made specifically for bikers. Please correct me if I'm wrong. (Big brother isn't watching you; you are watching him and figuring out where you are based on where his satellites are in relation to your position.)