Skip to main content

How does GPS work on my phone?

Before Space Force, there was NAVSTAR.

One of the best features of any great smartphone is the way it can determine where you are while you're there. This has some downsides — horrible location-based ads or tracking your movements come to mind — but being able to see where you are, where you need to be, and exactly how to get there is awesome. Your smartphone has replaced your TomTom. Thank goodness.

All this magic happens the same way on every phone from every company making them, regardless of the operating system. Several components work together to pinpoint you (often with amazing accuracy), and the software can intelligently pick the best way to make it happen. If you need very precise location information for something like navigation, GPS is usually called up to do the job. What follows is a short explainer of just how GPS works on your smartphone.

What is GPS?

GPS stands for Global Positioning System. It's a technology developed by the U.S. Navy and currently owned (yes, owned) by the U.S. government and overseen by its Air Force. It's free for everyone to use and primarily a North American utility even though GPS is commonly a regional name for the same sort of system in other locales.

GPS is a radio navigation system. It uses radio waves between satellites and a receiver inside your phone to provide location and time information to any software that needs to use it. You don't have to send any actual data back into space for GPS to work; you only need to be able to receive data from four or more of the 28 satellites in orbit that are dedicated for geolocation use.

GPS is precise, but it's slow and uses a lot of power on both ends.

Each satellite has its own internal atomic clock and sends a time-coded signal on a specific frequency. Your receiver chip determines which satellites are visible and unobstructed (that's important, and you'll read why in a bit) then starts gathering data from the satellites with the strongest signals. GPS data is slow, and this is by design — satellites run on rechargeable batteries, and sending a fast signal hundreds of thousands of miles would require more power — so it'll take up to a minute to get your geolocation.

Your phone's GPS receiver uses the data from these signals to triangulate where you are and what time it is. Notice the word triangulation and the mention above that four satellites are required for GPS to work. The fourth signal is used to determine altitude so you can get your geolocation data on a map with only three signals.

GPS receivers use a lot of power and require an unobstructed view of multiple satellites to work. Obstructions can include tall buildings, and that means the places where most of us live can (and does) have trouble getting the data it needs all of the time. That's where AGPS comes into the picture.

What is AGPS?

For starters, you probably use AGPS — Assisted Global Positioning System — when you want your location from your phone. As mentioned, GPS radios use a lot of power, and unless they stay in constant use, it can take up to a minute each and every time you get new data. Since you usually want your location while on the move, that can be a burden.

The "A" in AGPS stands for assisted; your cell connection helps GPS find you.

AGPS adds cellular location data to assist geolocation. Your phone carrier knows where you are since your phone "pings" cell towers. How precise this is will depend on the strength of the signal between your phone and the tower, but it's usually good enough to be used for location data.

Software on your phone feeds this raw cellular location data to the GPS receiver, which will periodically switch between GPS data and cellular location to get a very close approximation (within 50 meters or so) in real-time. In other words, GPS can use data collected by your phone from the cell site it is connected to in order to work faster and more accurately.

AGPS does send data out of your phone, but its data that was already being sent when it checks for cell towers in range. You're not charged for this, but you will need an active data plan to use AGPS.

Which is better?

That's an easy question: Neither, because you'll want to use both.

AGPS is required for best performance, using battery life and speed as metrics. We want our phone to know where we are in real-time, not to use a lot of battery power to do it and to be able to refresh whenever the software needs it without waiting too long for a good GPS lock. AGPS location isn't as precise as a true GPS location will be, but it's a good start, and the micro-adjustments that can be made with true GPS data when it refreshes makes up for most discrepancies.

As mentioned, AGPS needs a cellular connection. That means there are cases where GPS is preferred. Any time you have no data connection, you'll be unable to use cellular-assisted GPS. The same goes when you don't have a good enough connection to any cell towers in range of your phone. Most apps that require location also require a data connection, but some, like Geocaching apps, live on your phone's storage and will work while you're off the beaten path looking for hidden treasure.

If you have a need to share your location, you'll want to enable everything you can. Just remember, you can turn it all back off when you no longer need it.

Get More Pixel 4a

Google Pixel 4a

$349 at Amazon $350 at Best Buy



Source: androidcentral

Popular posts from this blog

How to watch England vs New Zealand: Live stream 2nd Test series cricket on

With the first Test ending in a draw, the series is on a knife edge at Edgbaston, as Joe Root's side look to put off the field controversies to one side and claim a much needed win against the Kiwis. Don't miss a single ball of the 2nd Test with our England vs New Zealand live stream guide below. The series has been somewhat overshadowed by the emergence of offensive historic tweets posted by Ollie Robinson who made his debut in the opening Test but has since been suspended. With the controversy still brewing amid interventions from politicians and accusations leveled at other members of the team, Root has a battle on his hands to keep his side focused on the game ahead. One positive for Root coming into the game is that they'll be playing in front of a near capacity crowd at Egbaston, with the overwhelming majority of the expected 18,000 spectators set to be cheering on the home side. The tourists have been delivered a huge blow coming intot his final match, with s

6 things Apple stole from Android at WWDC— and one that Google should steal

Every year, Apple and Google trade ideas for their newest versions of iOS and Android, respectively. But this year, during Apple's WWDC 2021, it seems like Apple purloined more than a few ideas that Google's integrated into Android over the last few years. Millions of iOS users won't get their hands on iOS 15 and iPadOS 15 until later this year, so until then, we don't know until then how the new features will fare in the real world. For now, here's a tongue-in-cheek look at six features Apple, um, borrowed from Android with its latest software releases. Jump to: iPad widgets and app drawer Live Text Apple Maps AR navigation iOS notifications New Siri capabilities Apple Photos Bonus: What Google needs to steal iPad widgets and app drawer iPad OS 15 introduced two big new updates for the iPad home screen today: widgets and the App Library. If you think this sounds awfully familiar, there's a good reason for that. 2020's iOS 14 introduced both

The Galaxy Watch 4 is coming soon — here's everything you need to know

Samsung's Galaxy-brain play: leaving Tizen behind for Wear OS. The Samsung Galaxy Watch 3, one of the best Android smartwatches , may have only just launched in November 2020, but the latest rumors out of South Korea suggest the company may already be developing its replacement — with some big changes and upgrades in the works meant to topple Apple from its smartwatch throne. There's no confirmation whether Samsung's 2021 smartwatch will be named the "Galaxy Watch 4" or adopt a new name entirely. However, we know that this new watch will run the new version of Wear OS, which would have a big impact on app support and Android phone connectivity. It could also feature a newer-faster chipset, which could put it leagues ahead of the best Wear OS watches . Details are fairly scarce so far, but we've scrounged up every known leak about specs, design leaks, and pricing, along with everything else we know so far about the Samsung Galaxy Watch 4. Samsung's bes

Rock out to your favorite tunes with $100 off Marshall's smart speaker

Cover all the audio basics with just one speaker: listen to music, control your smart home, and stream from multiple devices! The Marshall Stanmore II Bluetooth speaker is down to $249.99 at Amazon . While this speaker normally sells for $400, today's deal is the lowest price of the year. We have seen it go this low a couple of times, but if you missed out on those previous deals now is your chance to save $150 on a great device. Previous deals included the Bluetooth-only version, but that speaker is actually $350 at the moment so you're saving even more and getting Alexa built in. This isn't exactly a part of Amazon's early Prime Day deals , but the savings do seem to be coming at a pretty convenient time. Amazon has already been launching Prime Day savings way ahead of the big event, so if Marshall's deal doesn't work for you check out the other big ways you can save right now. You'll get a great low latency connection with low power consumption and n