Precise geolocation via Wi-Fi Positioning System

https://www.amoses.dev/blog/wifi-location/

by nicosalm • 8 months ago

256 114 8 months ago

ralsei2• 8 months ago

Good article, but you could also just use a VPN to trick it.

wsces• 8 months ago

No, a VPN would only change the source IP of your request which the author specifically states isn't how this system works: the browser uses its host OS' Location Services to self report its location based on GPS or Wi-Fi AP locations.

That said, I hope the service doesn't implicitly trust data sent by untrusted clients like web browsers, otherwise someone could just use something like this to send it a false location: https://chromewebstore.google.com/detail/spoof-geolocation/i...

ralsei2• 8 months ago

Ohh. Yeah I suppose that's what I meant. I thought a VPN also spoofed the location

oceanplexian• 8 months ago

Even if the browser was super locked down you could trivially spoof a few SSIDs broadcast from the desired area in theory..

bitwize• 8 months ago

A device can triangulate its own location locally, given the WiFi hotspots around it, and transmit that information via a JavaScript API. A VPN won't flummox this mechanism.

IshKebab2• 8 months ago

Some simple Tampermonkey patching would though.

Aachen2• 8 months ago

A device can triangulate its own location

Trilaterate (or multilaterate). Angulation uses angle, like a directional antenna, constructive/destructive interference for beamforming (this is how airplane landing systems work if I'm understanding it correctly), or optics like our two eyes, to find the angles to a target from known positions in order to determine its position in space

Trilateration is based on distances from known locations, determined either by signal delay (GNSS does that; newer cell towers also but call it "timing advance") or signal strength (used with both WiFis and cell towers)

locally, given the WiFi hotspots

You'll also need a local database with the hotspots' positions (usually those aren't actually measured but estimated from observations at different locations). I'm not aware of a device that ships with this, nor popular software that uses it as its primary method, as such databases are many gigabytes. Thus this is typically not local; you're sharing your data (thus location) with the server which then kindly tells you where it thinks you are

pkulak• 8 months ago

I use a Firefox preference to pin my location to a spot near, but not at, my house:

user_pref("geo.provider.network.url", 'data:application/json,{"location": {"lat": 45.0, "lng": -122.0}, "accuracy": 128.0}');

I _believe_ this also stops wifi data from leaking anywhere.

flutas• 8 months ago

There's also a plugin that allows varying levels of accuracy per-site. - LocationGuard

chrome: https://chromewebstore.google.com/detail/location-guard-v3/h...

firefox: https://addons.mozilla.org/en-US/firefox/addon/location-guar...

notafox• 8 months ago

Also, I see options:

    geo.provider.use_corelocation: true/false # presumably for tracking on MacOS

    geo.provider.use_geoclue: true/false # presumably for tracking Linux users with Geoclue2 provider [1]

    geo.enabled: true/false # presumably, turns the whole thing off

Some say[2][3], use_ options take precedence over network.url, so you need to set those to false.

It also appears[3][4], that setting geo.provider.testing to true might be required.

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1063572

[2] https://stackoverflow.com/questions/24932199/how-to-change-f...

[3] https://security.stackexchange.com/a/268825

[4] https://stackoverflow.com/a/24937564

denysvitali2• 8 months ago

I've recently vibe-coded "where-am-i", a small CLI that returns your approximate location using the technology described here.

https://github.com/denysvitali/where-am-i

Tbh, I think this geolocation method is amazing, and I'm grateful it exists, because GPS indoor really sucks.

jbmchuck• 8 months ago

Honest question - what's your use case for needing GPS indoors? I generally know where I am when I'm indoors :)

HPsquared• 8 months ago

It's useful in shopping malls, airports, train stations, car parks and so on. Anywhere you need to navigate a large complex.

denysvitali2• 8 months ago

Maybe indoors is the wrong term: as soon as you don't have direct sky visibility it's relatively hard to get a position.

Some examples: on a train, on the underground, in a train station, in a mall, in an office building, ...

mingus88• 8 months ago

Not OP but navigating large malls, subway terminals, etc is nice

mcdonje• 8 months ago

You're in a large building you're unfamiliar with. Particularly one with an unusual layout, like a mall or hospital.

0x4572• 8 months ago

Generally yes, but if you go to a giant mall, train station, airport then you usually don'y.

seba_dos12• 8 months ago

/usr/libexec/geoclue-2.0/demos/where-am-i

p1necone• 8 months ago

Is it common for North American universities to take attendance? Seems like a whole lot of effort to gain little and infantilize your students. They're paying tuition, and if they don't show up to class they get punished by not learning enough and subsequently failing their exams/assessments. And if they don't fail their exams/assessments then clearly mandating lecture attendance for them wasn't necessary anyway.

savanaly• 8 months ago

If you require attendance to graduate, then your degree signals conformity and grit, and thus has some value to show to employers who care about those stats but can't really measure them any other way.

dataflow4• 8 months ago

I think it's worth pondering why you feel paying tuition enters the assessment of the situation. The justification would seem to stand on its own either way, right? Or would your opinion change if tuition was free?

bigfishrunning3• 8 months ago

Mandatory attendance makes more sense if tuition is free, because it's not the student's resources that are being wasted, it's whoever is paying the universities.

wrs• 8 months ago

I was punished by getting into grad school, going to the "meet the faculty" party, and having my Algorithms professor greet me with "oh, you're the one who never came to class". (I can't resist pointing out, now that it's safe, that it seemed like his TA taught quite a few of his classes...)

foltik• 8 months ago

In my experience it’s common for large intro level classes. While I personally never liked these policies, I do think it’s beneficial to the average student to incentivize attendance. Think 18 year olds who aren’t able to self regulate or fully understand the consequences until it’s too late. A “pick yourself up by your bootstraps” mentality just hurts the average quality of education.

renewiltord• 8 months ago

You misunderstand. The customer is the government, which pays for student education through 'student loans'. The government is an absentee farmer who pays a farm labourer to produce a crop many years in the future. The labourer would rather take the money and plant nothing, so the absentee landlord farmer wants him to send photos of the seed being planted.

But why won't the crop grow on its own? It is strongly incentivized to live! And yet it does not. So you need to send photos of tilling the soil, planting the seed, watering, so that one day we might come there and see a harvested crop.

Ntrails• 8 months ago

if they don't show up to class they get punished by not learning enough and subsequently failing their exams/assessments

My (UK) University was very clear that attendance was not mandatory, but if you weren't attending lectures you were not going to get any extra help from the lecturers etc

I don't think that's an unreasonable position to take, but it's nice if you _know_ rather than _guess_ who bothered to make it in to class.

washadjeffmad• 8 months ago

It's a protection for the faculty and students.

If you fail someone who rarely attended class, and they claim that they did, asked you for support, and never received it, how might you defend yourself?

If you have an excellent student who encounters a hardship, how might you petition for leniency to allow them to drop without penalty beyond a cutoff, or delay submitting final grades until they can complete makeup work?

ginko• 8 months ago

Maybe it’s because I studied in Austria where universities generally provide very little handholding to students but I don’t understand the point of compulsory attendance in university lectures. If students think they can pass exams without attending the lectures then they should be able to do that. I certainly did that once or twice when I realized I needed some more credits before the end of the term. It’s a different thing with lab/exercise sessions but your lack of participation there would be noticed anyway.

shortrounddev2• 8 months ago

Compulsory attendance used to be far less common in colleges, but teenagers in America mature far more slowly than they used to and undergrads are still effectively children. Universities need to babysit them or they'll wreck the dropout rate

michaelt• 8 months ago

My university didn't take attendance either, but some in my country do. As I understand it, the reasons are:

1. Some students think they can skip class and catch up through self-study, but actually they can't. The same I'd-rather-be-partying attitude that stops them attending lectures also stops them finding time to self-study. College is the first time students' time management is put to the test, and some students can't handle it. Giving them some external motivation to get out of bed does them a favour, in the long term.

2. Some courses are discussion-and-debate oriented. Less so in engineering, moreso in arts subjects. If Socratic debate is a key part of the class, students who don't show up will of course lose grades - and accurate record keeping makes sure that's done fairly.

3. Some governments require certain reporting to ensure people getting student visas are, in fact, students. Taking attendance for foreign students is one way to satisfy this.

4. When someone fails a course they'll often lodge an appeal. Perhaps they'll say the course was badly taught, or the exam covered material that wasn't in the lectures. Knowing whether the student attended the lectures helps adjudicate such complaints fairly.

A highly ranked university that attracts smart, self-motivated students has less reason to take attendance - whereas a university with lots of students skipping class, failing and complaining has more reason.

aidenn0• 8 months ago

I graduated University in the US in 2004. I never took a class that had mandatory lecture attendance.

ninalanyon• 8 months ago

It was the same when I studied applied physics in England many years ago. No one checked or cared if we attended lectures in the physics and maths departments. In fact anyone could have attended the lectures even if they were not a student because there was always plenty of room. But the law department where my wife studied, at the same university, did check who was attending.

As for laboratory exercises in the physics department, they were in theory compulsory but still no one checked. The final year included a long experimental project that had to be documented and conclusions defended in a viva. Again no one formally checked that we actually did it but as we were grouped into small teams for this anyone who didn't pull their weight would have been reported by their fellow students and would not have had access to the experimental results which would have made it difficult to write it up and defend.

mig392• 8 months ago

I take attendance (the old-fashioned way) in my college classes for a couple of reasons:

- Some students are "sponsored" by scholarships or organizations that request attendance data. - I want to know the attendance record for a student who is asking for an extension, or extra-credit work, or some other informal accommodation. - I like to draw fancy graphs correlating attendance and final grades.

But other than that, I don't care if students are in class or not. They're adults. Learning is their responsibility.

incompatible• 8 months ago

My PC doesn't have any wireless connections and the Geolocation API always fails. I guess I'd fail this course (which is apparently correct, as I was supposed to be attending in person with a laptop.)

Edit: Presumably it would be possible to hack the browser to return a false position.

Edit: Make it a convenient browser add-on, perhaps. There must be other applications.

Edit: pkulak points out that you just have to set a Firefox option. Why do I even comment on things I know nothing about.

neilv4• 8 months ago

The root problem is that a lot of higher education is nurturing a culture of cheaters right now.

Your future doctors, scientists, government officials, etc... will have had to compete and gain coveted academic and career opportunities, in an environment that both has been heavily gamified, and is being overrun by cheaters.

Insulting measures like this TopHat practically endorses the culture of cheating, by telling students that they can't be trusted, and turning into yet another cheating challenge/task.

Schools with any integrity should be bending over backwards to find, nurture, and support students of integrity.

And to save those who only got admitted by being sketchy, but first semester is a chance to unlearn the bad lessons from before.

Not by treating them as criminals to be monitored, but by treating them like the respectable people they should aspire to be, and which the school expects and requires that they be.

And, for any hopelessly shitty students, who fail to honor this first semester extension of trust, the school should smack them to the curb. Lost tuition income, lost named buildings/chairs, and expensive lawsuits from helicopter parents, be damned.

munchler• 8 months ago

In this moral framework, would it be acceptable for the lecturer to take attendance orally, or is that also insulting?

neilv4• 8 months ago

The instructor clearly sets their expectations for attendance (whether it's mandatory, or otherwise), and then just expects everyone to follow that.

Centigonal• 8 months ago

It also doesn't help that our outrage-driven media overwhelmingly exposes us to cheaters.

Everyone's heard of Theranos, Enron, Martin Shkreli, and Bernie Madoff. This week, my 70+ year old aunt asked me about Charlie Javice and Frank. Yet, there are thousands of very successful people quietly building their castles who live and die in relative obscurity because their stories just aren't that thrilling.

If you spend a lot of time interacting with people in the latter category, or if you have them as your mentors, then you will be exposed to a model of what success through hard work and integrity looks like. If you don't, then it's very easy to think everyone successful is a cheater, and that cheating is the only way to break the ceiling into success.

torben-friis• 8 months ago

It’s not about individual people - it’s just scale, paired with Goodhart's law.

No number in a spreadsheet will tell you who’s the genuine student. The moment you’re ranking like that you lost.

Long term human interaction in reduced groups is far better at creating genuine environments. But of course, that system doesn’t scale, and it’s a breeding ground for nepotism.

FloorEgg2• 8 months ago

I have an inside perspective on this via an academic integrity company.

A couple weeks ago there was an exam in an R1 institution that double booked the facility so one section did the exam in person on campus and the other did it "from home". The score distribution of the in person exam was a typical bell curve, and the distribution of the online exam looking like a power-law curve with over half the students scoring 100%.

Thankfully this outraged the professor, and through a variety of means (which I will not disclose publicly) over 25% of the students were caught red handed. Actions are being taken against them, though I'm not sure how far they will go. The evidence against them is overwhelmingly conclusive. In some cases the evidence led to more evidence of cheating in other courses. It seems clear that more that 25% cheated, but I guess catching some is better than none.

As someone who is keenly aware of this crisis, I feel tiny bursts of relief when I see these small wins, though it does feel a bit like bailing an ocean with a teacup.

sneak2• 8 months ago

Catching cheaters is easy. The problem is that incentives are not aligned. Students are also customers, and you can’t simply fire a quarter of your customers and stay in business.

IshKebab2• 8 months ago

TL;DR: location API exists. Wifi-based location exists. American universities apparently use this to take "secure" attendance.

nlawalker2• 8 months ago

Oh wow, it's the modern version of the clicker, the physical device assigned to you at the beginning of the term used for classroom participation and attendance checking, and which was most definitely defeatable via "the unpatchable strategy of Having Friends".

montroser• 8 months ago

One time I worked at a zoom competitor, and our team got to prototype a "detect if these people are in the same room as each other" feature for dealing with echo cancellation etc, where everyone's laptop would emit a unique high frequency, and everyone's laptop would listen for other frequencies. Of course it worked in pristine conditions and fell down in the real world. But it was a fun experiment...

ctkhn2• 8 months ago

People need to learn manners, nobody should be using video calling without headphones. It's insane whenever someone joins and we hear all their background, feedback of whoever is speaking, etc as if nobody has ever told them to mute or stop using speaker in their life.

pinkgolem• 8 months ago

... I mean Google meet handles it pretty well

carstenhag• 8 months ago

This is about 3 people in a meeting room joining with their laptops, without a meeting room audio setup (or it being bad)

krisoft• 8 months ago

People need to learn manners, nobody should be using video calling without headphones.

OK? it still sucks even with headphones. Imagine the following scenario: You are in a meeting using your headphones as you suggest. A coworker a few seats away from you are in the same meeting using their own headsphones. When they talk you hear their real voice reach your ears first (this happens with even the best noise canceling headphones to some extent) and then you hear their voice with some delay from the meeting.

This is not about manners or headphones.

Better meeting software identifies when this is happening and they suppress the streamed voice of your coworker just for you.

spike021• 8 months ago

sounds like how Cisco Teams/Webex could detect if you're in a certain meeting room using an ultrasonic frequency.

everdrive• 8 months ago

where everyone's laptop would emit a unique high frequency,

This sounds like an awful idea.

https://www.science.org/content/article/sounds-you-cant-hear...

dewey• 8 months ago

That's what Google Meet does too: https://support.google.com/meet/answer/14263133?hl=en-NZ

tylervigen• 8 months ago

Microsoft Teams does this: https://techcommunity.microsoft.com/discussions/microsofttea...

paxys• 8 months ago

As the article mentions this tech has been in widespread use for over two decades now. You have likely used it on your phone today without knowing it. GPS is accurate but also very fickle (takes time to get a lock, battery hog, doesn't work great when surrounded by buildings, doesn't work great when inside a building, doesn't work in bad weather). Wifi data is plentiful today in every urban setting, and you can get an exact location in under a second.

friedgil• 8 months ago

Small digression: did you know that, until May 2000, GPS satellites (which are owned and operated by the United States Space Force) provided the general public a signal with intentional error built into it?

What the hell? Why?

Jtsummers• 8 months ago

It was to degrade accuracy. Military (and presumably other gov't and allied gov't owned systems) were able to get more accurate signals. The degraded signals meant that someone couldn't use commercial GPS as a guidance system or for similar applications.

godsinhisheaven• 8 months ago

Something something Yujio Hanma

MaulingMonkey• 8 months ago

GPS started as a U.S. Department of Defense project, and they had qualms about freely giving the high accuracy positioning information they found so very useful for e.g. targeting bombs and missiles, to every unverified third party in the world. Depending on your preferred flavor of jadedness, one could say it was because of security concerns... or one could say it was because said third parties hadn't paid off the military industrial complex enough!

00N8• 8 months ago

They wanted to keep accurate global positioning as a US military exclusive capability. It's definitely useful for guided munitions, & alternative satellite positioning systems didn't exist or were less mature at the time, so US GPS was the only system one could realistically use for that. A missile able to hit a target within a 3 meter radius is vastly more effective than one that can only hit within 100m, for instance.

There are still some restrictions around this sort of thing: IIRC a GPS receiver for sale to the public isn't allowed to give accurate data if it's too high up &/or moving too fast, to prevent unauthorized usage in ICBMs & other similar weapons. I think there would be a lot of red tape involved if you wanted to buy an unrestricted GPS device without this limitation.

4gotunameagain2• 8 months ago

Which is idiotic, because nowadays it is trivial to build your own GPS received compared to the complexity of building a reliable ICBM.

0x4572• 8 months ago

Error was built in to reduce precision and make it harder to use them for targeting. It stopped being useful once there were other constellations available.

GPS receivers sold to public also required to not operate at certain altitude/speed to prevent it from being used in ballistic (and probably other kinds?) missiles.

coin• 8 months ago

https://www.gps.gov/selective-availability https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_...

bigiain• 8 months ago

I assume that smart comp sci kids already have some sort of proxy running on an Android phone that publishes the current in-classroom WiFi environment, and a browser plugin or Linux hack that their stay-at-home friends can run that intercepts the geolocation calls and spoofs the responses with what the in-classroom android phone is seeing.

Genwald• 8 months ago

The API just returns coordinates to the website and it's fairly easy to spoof on major browsers. You'd just need to know where the classroom is.

UltraSane2• 8 months ago

I've had companies send us laptops for VPN access that had LTE modems and GPS specifically for location verification before granting access to the VPN.

sneak2• 8 months ago

Imagine having your services so poorly secured or authenticated that you need to protect Layer 3 access this tightly.

UltraSane2• 8 months ago

It is just another layer of authentication.

m463• 8 months ago

Apple’s instructional opt out page (appending _nomap) to the SSID.

this is good information.

on the other hand, it is pretty impossible to turn off wifi on some apple computers. (when I look at wifi, I get a greyed out off toggle)

You have to get into csrutil to disable the chips from powering up.

rudimentary_phy• 8 months ago

Times are getting so much tougher. I remember my early morning organic chemistry classes using top hat. I never showed up to class, but I had my top hat app open.

The answers were usually kept simple, so I'd guess things like 0 or 1 (the questions were never written in the app). I think I ended up with 60% or so on them, which was nice, since it was a bonus component meant to be a little boost to the grade anyways.

doctor_radium• 8 months ago

I held onto Symbian longer than I should have, but am surprised this practice hadn't crossed my path before now. IMHO it's insidious. It's one thing for a Google Street View car to war scan my WiFi router, but another for my own phone to secretly rat me out. Not that I use Location myself, but I can't stop other members of the household. I assume this is yet another practice that Android forks like GrapheneOS disables?

DANmode3• 8 months ago

Gives you verifiable control over, at least.

tnorgaard• 8 months ago

Does the "Stop broadcasting SSID" option in most Wifi access points / routers prevent wardriving or is the BSSID still leaked?

zamadatix• 8 months ago

In this case the AP still beacons (which includes the BSSID), just with the SSID field set to "".

palata2• 8 months ago

Now the question: can you spoof your location? Say you are an admin on your system (for instance you run a Linux distro), can you make your OS return the same list of SSID/BSSIDs as your friend who is in the classroom (or as you recorded the day before) to pretend you are there?

Would be a fun experiment, and a nice follow-up post :-).

toomuchtodo• 8 months ago

https://github.com/adamhrv/skylift but doesn’t use the OS, it broadcasts the necessary beacons with ESP8266 / ESP32 hardware.

palata2• 8 months ago

Nice! Still would be cool to do it right from the computer.

ycombinatrix• 8 months ago

How come this project needs multiple Skylift devices to work best?

Since wifi antennas are generally not directional, shouldn't one Skylift device be able to broadcast each wifi beacon frame with a different transmission power?

varenc• 8 months ago

I've experienced this unintentionally when I've moved and taken my access point with me. Fresh after moving in, I'll pull out my phone and it'll tell me I'm still at my old house's location, because its using the proximity to my wifi AP's BSSID to determine that. Waited another 30 seconds and it corrected itself.

abixb• 8 months ago

Glad to see a fellow Madisonian make it to HN frontpage. Great work!

potsandpans• 8 months ago

I don't think it's appropriate for a professor to use this feature. Am I in the minority?

mig392• 8 months ago

It's a good sales job. Someone sold them a "high tech" solution for a problem that's already been solved. We had attendance rolls long before we had computers.

djoldman• 8 months ago

The question is, can we patch our browser to respond with whatever we want when getCurrentPosition() is called?

Then we can be wherever we want, super precisely!

Precise geolocation via Wi-Fi Positioning System

Related Stories