Hacker News Reader

Comment by caymanjim | Hacker News Reader

Do you want a self-hosted location tracker because you don't want someone else tracking you? Because it's not going to help. Your cell company knows where you are at all times, and even with location turned off, your OS is reporting enough information to either Google or Apple at all times to know where you are to within a few feet.

View on HN

I know I cant avoid cell companies, but I can at least limit how much Google knows (or any other company that requires always on location). The problem is though, the data I can get from my location history from Google is really useful for me so it's been a privacy trade off I've taken.

I keep Google location history on so I can have evidence of where I was.

As if that was admissible. Easily faked by leaving your device at home.

Paired with other metadata (which can also be faked) I’d bet a jury would find the data quite convincing

From the article, which talks about the police being able to get a warrant on you based on nothing more than you being in the wrong place at the wrong time, and from the fact that the police convict innocent people based on flimsy evidence all the time, I'd say at this point you're much more likely to get falsely convicted based on your location than exonerated.

Has anyone ever been exonerated based on their Google location history?

That's not true: when location is turned off, location is turned off. Apple still has a loophole where turning off Bluetooth doesn't turn off Bluetooth, but location should be "fixed"

I thought the Bluetooth thing only applied from the quick menu. I've been told if you disable it in Settings that it will actually turn it off.

This is true. And when you turn it off from control center, it says 'disconnecting bluetooth devices until tomorrow', so it's clear that disabling it means "stop all BT connections except for my Watch".

Your cell phone company knows the tower you are talking to and probably which (directional) antenna you are talking to. Antennas are in the process of getting a lot more directional with 5G, so they'll soon go from trivially being able to track you within a block or two to within a meter or two.

It's not great.

The core records of a cell phone company are at a cell level, which often are configured in a 120-degree sectors from a tower.

If they really want, they can see the distance from the tower because that's a requirement for the communications protocol to work (LTE at least expects to account for lightspeed delay in allocating transmission slots) and gets measured during the communications, so the operator should be able to see that distance to the granularity of something like 100m (or is it less nowadays?); but AFAIK that's usually not stored unless you're in a 911 call or perhaps with some tracing warrant.

These newfangled beamforming systems can alter the direction of transmission to optimize signal quality for your phone. How can they do that if the system cannot locate a handset with great accuracy?

Beams don't have to be that accurate to boost signal quality.

This is also speculation on my part but I'd suspect they're targeting specific clusters of devices in an area and using multiplexing than having dozens of radios on one tower.

I have no idea about what information the (5G?) beamforming protocols use; perhaps they have figured out a way for some "angle discovery" as part of the protocol handshake or perhaps they just require the device send GPS data for that adjustment (and in the absence of that data would just skip beamforming, getting worse rates); but the distance information for the 4G/LTE timing system would be an inherent part of the protocol even if the device does not have GPS enabled and is based on literally measuring the round-trip timing.

From Wikipedia/MIMO:

”To correctly form a beam, the transmitter needs to understand the characteristics of the channel. This process is called channel sounding or channel estimation. A known signal is sent to the mobile device that enables it to build a picture of the channel environment. The mobile device sends back the channel characteristics to the transmitter. The transmitter can then apply the correct phase and amplitude adjustments to form a beam directed at the mobile device. This is called a closed-loop MIMO system.”

As far as we know, though, the police haven't (yet) been able to demand Verizon turn over the records of everyone who sent near a crime scene at 2pm, though, have they?

I feel like Google's location history is basically built for that kind of thing.

Cell phone towers can still track you, unless you don't have a SIM card.

Until mmWave 5G becomes the norm, LTE towers aren't as accurate as the GPS data obtained by Google. The difference between 30 meters of accuracy[0] and a few meters with Galileo/GPS[1] could be the difference of a search yielding everyone in one building and finding everyone in the neighboring buildings on the same block.

0: https://www.marketingdive.com/ex/mobilemarketer/cms/news/res...

1: https://www.deingenieur.nl/artikel/after-13-years-galileo-sa...

They can still track the device by IMEI, because the radio connects to the base station. SIM is only necessary to register on a network. You can still call emergency services even without a SIM.

Reply on news.ycombinator.com