How your smartphone makes it easier to track your movements

How can my phone track me?

There are a few different ways, Modern smartphones have made it far easier to track people’s movements with location services built into various apps, providing a neat history of your daily movements. But you don’t have to check in on Facebook or give Google permission to track your location data for someone to find you. Even before smartphones were really a thing, there was triangulation.

What is triangulation?

When you turn your mobile phone on, it automatically connects your phone and Sim card to the nearest mobile phone mast, giving you access to the network. When it does that, it sends two numbers, one identifying the Sim card and the other identifying the phone (the IMEI number), to the network. The more activity on your phone – calls, messages – the more often it will connect to base stations. Information from the base stations can then be used to triangulate a location.

But even if you don’t make a single call or send a message, your phone will continue to “check in” periodically; if you move between locations, your phone will register on the new base stations you pass.

How reliable is triangulation?

The triangulation is pretty reliable, according to experts. Although there are many more masts in a city than there are in rural areas of Ireland, each time your phone connects to a mast, it will also give away how far away from the mast its current location is. Once you have a second mast to ping, you can get a reasonably accurate location for the phone.

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Where does the information come from?

Mobile phone networks collect network usage data. Under provisions of Ireland’s data retention laws – which were called into question by this morning’s ruling – mobile phone companies were required by law to retain some information for a set period of time. For example, call-related location data needed to be kept for one year, and data collected in relation to an internet service provider needed only be kept for one year.

Do I need to give permission for my data to be used?

It depends. Up until this judgment certain State bodies – An Garda Síochána, the Defence Forces, Revenue Commissioners and the Competition & Consumer Protection Commission – could request access to this information, but only under certain circumstances. That included law enforcement and State security purposes, or to save human life. The judgment today now calls into question.

Outside of that, the data can only be accessed by service providers if you have requested and consented to it, or if a court directs it, or if the Data Protection Commissioner gives permission.

What about apps using my location data?

Modern smartphones are almost constantly connected to the internet, sending emails, updating your locations for maps and advertisers, updating your Facebook feed and Twitter timeline. If you have location services enabled, phones can keep track of your location using a mix of GPS, wifi and mobile networks.

How much data is collected depends on what you use your phone for. When installing apps, you’ll notice a lot of them asking for permission to access your location data.

There are many situations in which this is warranted: maps, for example, need location data to give you accurate directions; news sites may use it to make sure you are served local headlines in addition to international ones. And there are plenty of instances where granting access to location data just means you get served up a load of local ads. The choice is yours to grant permission or not, although some apps are useless without it.

What if I don’t give my permission?

In theory, apps should not be tracking your location or using your data without your permission, something data privacy laws have made clear. If you say no, that decision stands.

However, tech giant Google found itself under fire recently when it was discovered that it was tracking Android users through the addresses of nearby mobile phone towers. That still happened even if users had disabled location services; Google says it has since changed the practice.

And a few months ago, an AP investigation found Google apps were still collecting time-stamped data, even if users had told the apps to pause tracking their location history. Users also needed to disable web and app activity, which was saving location markers to their accounts.

Is there any way to stop my phone giving away its location?

You can switch off location services and background data, or even turn off data. But as previous cases indicate, that may not be enough to stop your location being tracked.

If you want to avoid your phone’s location being tracked at all, the only way to be sure is to turn it off, and remove the sim card. Just in case.