Well, let's think this through. I agree that the exact physical location wouldn't show up without a Trace, but even if the signal is bouncing off satellites it has to connect to some grid somewhere at some point. Doc doesn't have access to the global grids without Brute Force or Hack on the Fly, which I presume he wouldn't use for Overwatch Score reasons. Thus he's stuck using the Local Grid if he wants to avoid grid hopping penalties (which he didn't take), but his Firewall protects it while he's using it so the concern is more about its visibility while not in use. From a fluff perspective, we can say that the satellite icon appears in geosynchronous orbit above the PCC. So, one icon out of many, but that "many" is a finite number.
Given the stakes (the obelisk) and the relatively low level of security that many satellite links would have, it stands to reason that a team of dedicated hackers could work their way through the list. Slapping a couple marks and a running a Trace would only take 3 seconds for someone running in VR. So 20 a minute, 1200 an hour, maybe 10000 overnight for a single hacker (probably souped up on Long Haul). He could throw them off by grid hopping to another local or public grid, but that would slow down his own Matrix activities. Plus, the danger isn't so much the time when Doc is actively using it (since his Firewall would protect it) but rather the time when Doc isn't using it. He could leave it on a different grid while not using it, but why bother?
Again, would they find you? Probably not, at least not right away, but the one way to be sure is to turn it off while not in use.
Separately, a new IC post is up. I'm doing my best to stick to the canon as much as possible, which involves a lot of time with 3rd Edition sourcebooks. I am diverging from it occasionally, usually when the canon conflicts itself or when we're venturing into undefined territory. For example, Street Grimoire gives the estimated size of the DIMR at 375 globally. This doesn't synch up well with the description of the DIMR from previous editions, so I've moved away from it toward something I think is more reasonable.