FBI agents track cell phones that pinged near the Capitol • Hacker News Board

Re: FBI agents track cell phones that pinged near the Capitol

#381

Post by BurningFrog » Sun, Jan 24, 2021, 1:32 AM UTC

Dylan16807 wrote: post #312

BurningFrog wrote: post #216

Earlier quoted context omitted.

GPS does not use triangulation. It does some real dark arts physics wizardry to compute a position. Nothing like that can be done for cell phone signals.

Technically it's not triangulation, it's trilateration. But the math is not significantly harder. The only meaningful quirk is that without a perfect clock you don't know the exact distances to each satellite, instead you have distances a+n, b+n, c+n, etc. Still though, you're just looking for the spot where your numbers line up. There's no wizardry in the "compute a position" part of GPS.

OK, I looked it up, and the GPS system is a different and simpler from what I thought I heard.

In the end the math is indeed similar, but how it gets there is quite different.

For one thing, each satellite carries an atomic clock to make things work. And the receiver locates itself by listening to signals, while triangulation is several receivers working together to locate a transmitter.

Re: FBI agents track cell phones that pinged near the Capitol

#382

Post by throwaway_kufu » Sun, Jan 24, 2021, 1:33 AM UTC

djrogers wrote: post #367

A lot of comments here about ‘overreach’ ‘privacy violations’ and such as if the FBI is showing up and accusing these people of crimes. If you actually read the story, the one person who they quote explains they weren’t suspected of anything but the agents asked for any photos they had of the events. This is straight up classic police legwork...

classic police work...always starts with contacting a person of interest and saying “your not a suspect, we just want you to come down and answer a few questions.” If you don’t, it’s suspicious and they will continuing investigating you as a person of interest. If you do, they will conclude you were suspiciously nervous and begin building by their case.

Now they show up to your house telling you they “pinged” your phone near a suspected crime “but your not a suspect, we just want to see the pictures on your phone”. Refuse to show them, and they already know you posted one or more (maybe subsequently deleted it) and maybe it’s obstruction of justice. Deny you have any, and it’s lying to law enforcement.

Re: FBI agents track cell phones that pinged near the Capitol

#383

Post by asdfthrowawayyy » Sun, Jan 24, 2021, 1:35 AM UTC

Because that's legal. Totally acceptable under the U.S. Constitution /s

Re: FBI agents track cell phones that pinged near the Capitol

#384

Post by BurningFrog » Sun, Jan 24, 2021, 1:36 AM UTC

sobriquet9 wrote: post #254

BurningFrog wrote: post #216

Earlier quoted context omitted.

GPS does not use triangulation. It does some real dark arts physics wizardry to compute a position. Nothing like that can be done for cell phone signals.

Both GPS receivers and cell phone towers use the same basic approach based on the time it takes for the signal to travel between transmitter and receiver. The only substantial difference is that in case of GPS the calculation happens on the receiver side (GPS signals only go in one direction), while cellular service providers calculate time advance on the tower side.

AFAIK, cell towers don't even calculate phone position beyond what's needed to determine which tower should handle it.

Maybe there is an element of triangulation in that, but it's far less precise and ambitious than GPS.

Re: FBI agents track cell phones that pinged near the Capitol

#385

Post by javajosh » Sun, Jan 24, 2021, 1:36 AM UTC

babygoat wrote: post #358

javajosh wrote: post #338

Earlier quoted context omitted.

Well, if you agree with that advice then you shouldn't say anything in public either, e.g. here on HN, since that too can be used against you.

Are you talking about getting downvoted? Or how are people using things against one other on HN?

Thanks for the clarifying question, instead of an attack. I mean that anything you say that is publicly accessible can be used against you. Consider that you are charged with, I don't know, theft of a Coke. And you have a twitter account where you say you love Coke so much, but hate that its so expensive. This could very well be used against you, as it goes to a general motive. In the same way, HN discussions are wide ranging and could be used by a prosecutor in a similar way. And indeed, just posting here at all on a site with "hacker" in its title is inherently risky.

Re: FBI agents track cell phones that pinged near the Capitol

#386

Post by throwaway_kufu » Sun, Jan 24, 2021, 1:38 AM UTC

BurningFrog wrote: post #207

suifbwish wrote: post #77

Earlier quoted context omitted.

3 raises a very interesting and somewhat concerning possibility. In the near future as AI develops more in the crime detection arena you may become a suspect for crimes occurring in your geographical area based on things you are not doing or based on some set of states your smart devices have that match a statistical model of a suspicious person. The idea of becoming a suspect because you didn’t touch your smartphone…

You can become a suspect for all sorts of random things you have no control over, like being near a crime, knowing certain people, etc. I don't see how it can work any other way.

Being near a crime when it occurred is entirely different than your phone being at your house when a crime occurred somewhere else.

Re: FBI agents track cell phones that pinged near the Capitol

#387

Post by jdbernard » Sun, Jan 24, 2021, 1:41 AM UTC

seany wrote: post #302

This is terrifying. I swear the tech community would have been universally against this just a few years ago. What happened?

I think there are still just as many of us who are against it as there were years ago, we're just no longer as vocal about it. A lot of us have given up being perceived as "doomsday" prophets. Mainstream culture doesn't really believe or care about mass surveillance until it personally affects them negatively.

Re: FBI agents track cell phones that pinged near the Capitol

#388

Post by aikinai » Sun, Jan 24, 2021, 1:41 AM UTC

fatsdomino001 wrote: post #371

bastardoperator wrote: post #359

Earlier quoted context omitted.

These folks weren't smart enough to leave their tracking devices at home and a ton of them filmed their crimes. Everyone has a right to remain silent, but it's not going to help in most of these cases where the evidence is so abundant.

I wonder if these same techniques will be used to track down all the rioters and looters from this past summer. Or is it just used against particular groups?

That’s some next-level reality distortion to frame this as “against particular groups.” Unless you define the “particular group” as people that directly attack the heart of the government.

Re: FBI agents track cell phones that pinged near the Capitol

#389

Post by kortilla » Sun, Jan 24, 2021, 1:43 AM UTC

inefficient wrote: post #324

lawnchair_larry wrote: post #311

Earlier quoted context omitted.

This is just wrong on so many levels. You even included the widely debunked (even by her own colleagues!) Nikole Hannah-Jones 1619 project lies. Cops do not care if you are “weird”. Police do in fact exist to enforce the law. It really is that simple.

Well that's just blatantly not true. They aren't even required to know the laws and can enforce laws that they think exist even if they do not. See Heien vs North Carolina. Police exist to "keep the peace." The question is whose peace are they keeping. Well I suppose the reaction of police at the Jan. 6 insurrection vs that of the BLM protests tells us a little. Or the union busting police did in the past. Or blockin…

> Well I suppose the reaction of police at the Jan. 6 insurrection vs that of the BLM protests tells us a little.

They shot a woman in the neck. What’s the difference you’re trying to portray?

Re: FBI agents track cell phones that pinged near the Capitol

#390

Post by stretchcat » Sun, Jan 24, 2021, 1:50 AM UTC

konjin wrote: post #369

seamyb88 wrote: post #362

Earlier quoted context omitted.

There are some pretty poor attempts to justify it, but "it's not that our police are bad, it's that our News is brilliant" has to be up there.

The US isn't better or worse than Europe, it's different. Having lived in both the hypocrisy of Europeans when it comes to police brutality to gypsies is astonishing, doubly so since I'm half gypsy but white enough to get a free pass and get told how bad 'they' are.

Usually it's around this time that some European chimes in with some bullshit about how it's not racism when it's against gypsies. Hopefully this time they spare us.